Talk:Climate change

This article was the subject of a Wiki Education Foundation-supported course assignment, between 6 January 2020 and 25 April 2020. Further details are available on the course page. Student editor(s): Sofiahsantamaria (article contribs).

Proposed Changes to Responses Subtopic

I’ve been looking at revising the Responses/mitigation subtopic. This has included reviewing the following reports: UNEP Emissions Gap 2019; IPCC, 2014: Climate Change 2014: Mitigation of Climate Change; IPCC, 2018: Global Warming of 1.5°C; RENEWABLES 2019; United in Science-UNEP; Negative Emissions Technologies....NAP (2019); IRENA-2050 Roadmap; Achieving the Paris Climate Agreement Goals, UTS-Sydney; as well as additional information from the references from WP-GW footnotes 209; 212; 218; 219; 220; 222; 223, 224; 225; 226; and 227. The outline and some of the text from the full Climate Change Mitigation article is also helpful.

I’ve come to think that the Responses subtopic could be reorganized and strengthened a bit, mainly in the mitigation section. For that section, the UNEP 2019 and AR5 WG3 reports, along with the outline and some related material from the WP-Climate Change Mitigation article, provide good organization examples for the text. Based on those information sources, I would propose the following outline for this subtopic (I imagine @Hedgehoque: and @Chidgk1: could provide some great insights on this as well, given their work to improve this subtopic during the recent peer review):

Responses

Minor edits to the intro. Add a brief mention of climate engineering.

Mitigation

• Carbon budgets for 1.5 C and 2C - Source:AR5 WG3 pages referenced at WP-GW article footnote 206
• Required 2030 and 2050 reductions beyond current commitments in order to achieve 1.5 and/or 2C by 2100. Sources:UNEP Table ES.1, Figure ES.4, AR5 WG3 Fig. SPM 7
• Principal mitigation technologies - PV, wind, hydro, geothermal, nuclear, biofuels, CCS. Sources: UNEP Table ES.3, NAP Table S.1, GW footnotes 210, 211, 212, 213, 214, 215 and related text.
• Potential reduction strategies for:
  • Energy Systems - Increasing RE in electricity, increasing electricity as percent of overall energy supply, coal plant phase out, elimination of fossil fuel subsidies. Sources: UNEP Table ES.3; AR5 WG3 pp. 69-70 & Fig. 7.14, Ch 7.5; IRENA p.48.
  • Transport - Increase in EVs, low carbon (hydrogen) fuel substitution for transport modes like shipping, changes in transportation patterns (mass transit) Sources: UNEP Table ES.3 & p.49; AR5 WG3 pp.72-74, Ch. 8.3; IRENA p. 48.
  • Buildings - Decarbonizing building energy through electrificcation (heat pumps), low energy building codes. Source: AR5 WG3 p.23, pp.78-81, Ch. 9.3; IRENA p.49.
  • Industry - Production efficiency, materials efficiency, more intensive product use, reduced demand. Source: AR5 WG3 pp.81-85, Ch. 10.3; IRENA p. 49.
  • Ag/Forestry - aforestation, sustainable forest management, reduced deforestation - Sources: AR5 WG3 pp. 86-89, Ch. 11.3; NAP 2019 Table S.1; GW footnotes 216, 217 and related text.
  • Individual actions to reduce carbon footprints - driving an EV/reducing vehicles miles, adopting plant based diet, limiting consumption of goods/services, foregoing air travel. Source: GW footnotes 225, 226, 227, 228 and related text.
• Policies and Measures
  • Policy options
  • Carbon tax, emissions trading. Source: GW footnotes 219, 220 and related text.
  • Phaseout of fossil fuels subsidies, increased RE subsidies. Source: Footnotes 221, 222 and related text.
  • Technology/regulatory controls - Vehicle efficiency standards, CO2 controls on fossil fuel plants. Citations needed.
• Costs and Benefits
  • Costs/benefits - Comparison of costs/benefits for BAU and 2C compatible investments. Sources: AR5 WG3 Table SPM2, p.15, pp.57-59 Chapters 7.8-9, & Table 7.3 for electrification (costs are outdated); GW footnote 209 and related text; IRENA Figure 11.
  • Other Co-benefits - Sources: AR5 WG3 Figure SPM 6, pp. 16-17, Box TS-11; GW footnotes 209, 229 and related text.

Adaptation - No specific changes proposed at this point, although I think this section could also be strengthened a bit.

Climate Engineering - This section needs updating and revision. I would suggest it focus on items that are not (like CCS and ag/forestry related CDR) included in the mitigation section outline above. For example, it could focus more on SRM, or ocean related CDR technologies.

I think if this kind of outline could be expanded to closer to 1700 words (from the current 850 or so in the current section), it would help the reader get a better understanding of the issues involved in mitigation/adaptation. I think the main additions to the current text would be those associated with the carbon budget and 2050 reduction target bullets, and the bullets for the specific reduction strategies. But I think these are important additions; they were pretty much the gist of the AR5 WG3 report. I use the 1700 word count target because that is the amount of text currently included in the Effects subtopic, and I think understanding the approaches to dealing with GW/CC is about as important to readers as understanding GW/CC effects...and I would put both of these at or near the top of the kinds of information readers are looking for in this article.

I am looking for feedback on a couple of points.

• Does this outline seem appropriate? I am sure it could be improved on, and welcome any suggested improvements, but does the overall structure seem ok?

I think your outline is definitely an improvement on what is there now, but I think "policies" should be before "Principal mitigation technologies" as the policies are more important than the technologies in my opinion. Re cost/benefits as far as I understand it it is already proven and mentioned somewhere in this article that 2C has a global net benefit, so I think BAU should be omitted, but if there are reliable sources for the costs and benefits of 1.5C maybe you or someone else could first bash a section into Economics of global warming (which looks pretty dire) and if people like it you could summarise it here? I am not an economist but I am not sure increased RE subsidies are actually needed if (Carbon tax or emissions trading) and Phaseout of fossil fuels subsidies are implemented? https://www.forbes.com/sites/oliverwyman/2020/01/14/why-its-too-soon-to-let-renewable-energy-subsidies-expire/#64a920e31e02 seems to say RE subsidies are still needed but their examples of China and USA are countries which still subsidize fossil fuels and in UK wind subsidies will be gone in a few years time according to https://www.theguardian.com/environment/2019/sep/20/new-windfarms-taxpayers-subsidies-record-low. Probably increased capital investment in RE is needed, but not sure that is a "subsidy" if the investment pays back at a reasonable profit? But maybe the sources say that increased RE subsidies are a viable alternative to (Carbon tax or emissions trading)? That seems unlikely. I cannot see any link from this article to Climate justice - unless there is already a link via a redirect it should be linked from somewhere in this article. Chidgk1 (talk) 11:49, 6 May 2020 (UTC)

Well structured. Technologies before policies would provide a better flow of comprehension. One remark about subsidies vs carbon tax: There is one more factor. Complicated regulations, grid charges, slow administration can easily distract RE investors. Fossil fuel substitution is not only a question of competitiveness but also of political will. Hedgehoque (talk) 21:48, 7 May 2020 (UTC)

Thanks for that suggestion @Hedgehoque:. If you have any recommended references on the issue of the various impediments to RE investments, that would be helpful.Dtetta (talk) 20:28, 8 May 2020 (UTC)

• Does it make sense to expand the Response subtopic to more closely match the length of the Effects subtopic?Dtetta (talk) 23:21, 5 May 2020 (UTC)

Sounds sensible. Chidgk1 (talk) 11:49, 6 May 2020 (UTC)

Agree. Hedgehoque (talk) 21:48, 7 May 2020 (UTC)

Thanks for those suggestion @Chidgk1:, and for those additional references. I will look into the points you’re making about RE subsidies, investments, and net benefits as I develop some proposed language, which I will post here before making any edits. And I agree that there needs to be a reference to climate justice in this section - good catch. I’ll also take a look at how I might change the relative position of policies versus the technologies themselves. In looking at the major reports, however, they seem to set up a context by describing the technologies first, and then provide specific strategies and policies for implementing those technologies to various degrees. But I will see if I can figure out a way to implement your suggestion.Dtetta (talk) 18:36, 7 May 2020 (UTC)

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Below is text from my proposed revisions to the mitigation section. I think the word count is around 1500. There are still a couple of citations I need to select. But other than that I think it’s pretty much finished. Explanatory notes are in italics.

I edited the introductory paragraph to focus more on carbon budget and needed reductions concepts.

Mitigation

Climate change can be mitigated by reducing greenhouse gas emissions or by enhancing the capacity of carbon sinks to absorb greenhouse gases from the atmosphere. In order to limit global warming to less than 1.5°C with a high likelihood of success, the IPCC estimates that global GHG emissions will need to be net zero by 2050 SR15 SPM p.15 & Fig. 3a, or by 2070 with a 2°C target. To make progress towards that goal, UNEP estimates that, within the next decade, countries will need to triple the amount of reductions they have committed to in their current Paris agreements UNEP Table ES1.

I expanded the title of the technology section and edited it in line with the outline I posted. I tried to preserve as much of the original text as I could. I thought some of the text from the policies and measures section worked better in this section, so I moved those sentences here.

Technologies, Nature Based Methods, and Individual Action

There are several forms of renewable energy in use today that can be further developed to help achieve greenhouse gas reductions. Solar installations range from small rooftop solar systems to large solar farms that can power thousands of homes. Wind farms, often consisting of hundreds of individual turbines spread out over large areas, can be built on land or offshore. Hydroelectric dams have historically been a major source of energy for many countries. For smaller countries with suitable geology, geothermal energy production provides a large portion of their energy needs. The term bioenergy includes energy produced from burning crops, waste wood, and trees; similar to how fossil fuels are used to create energy. It is also used to designate liquid fuels, such as ethanol or biodiesel, that are produced from crops.

Renewable energy technologies are technically capable of supplying several times the world’s current energy needs UTS Table 7.1, and have seen substantial growth and progress over the last few years AR5 SPM.4.2.2, such that solar PV and wind are currently among the cheapest sources of new power generation UNEP Fig. ES.5 p.XXIV. Renewable energy also has the largest share of current electricity generation investment IEA 2019 p.9. However, fossil fuels continue to dominate world energy supplies. In 2017 fossil fuels produced 79% of the world’s energy, with renewable sources accounting for around 10%REN 2019 Fig.1 p 31.

There are obstacles to the more rapid development of renewable energy and its substitution for fossil fuel in the overall energy supply. Environmental and land use concerns are sometimes associated with large solar, wind and hydropower projects UCS 2013. Solar and wind power also require energy storage systems and other modifications to the electricity grid to operate effectively UCS 2013. The use of rare metals and other hazardous materials has also been raised as a concern with solar power UCS 2013. The use of bioenergy is often not carbon neutral, and may bring negative consequences for food security UCS 2013. There are also a variety of institutional, regulatory, financial and social barriers also associated with these technologies SR15 SPM pp.15-16, SR15 Ch. 4.3.1.1, SR15 Table 4.11, and most climate change policies are designed to help overcome them.

Carbon capture and storage is another method to reduce CO2 emissions from fossil fuel plants. CCS is a three-step process that includes: capture of CO2 from power plants, transport of the captured and compressed CO2 (usually in pipelines), and injection of the CO2 in deep underground rock formations EPA. The large scale use of this technology remains unproven, and its use is considered to have major risks in achieving permanent greenhouse reductions SR15 SPM p.34.

Greenhouse gas emissions can also be offset by enhancing earth’s land carbon sink to sequester significantly larger amounts of CO2 beyond current naturally occurring levels. Forest preservation, reforestation and improved forest management are some principal means of accomplishing this. Soils can also sequester large quantities of CO2, and soil management on croplands and grasslands can be another effective mitigation technology [ WRI 2019]. As with renewable energy technologies, barriers here can often be addressed with the appropriate policies SR15 SPM p.16, Ch. 4.3.2. Further global warming may also reduce the effectiveness of the forest and agricultural soil carbon sinks Citation needed.

There are also a number of actions that individuals can take to reduce their carbon footprint - these include driving an EV or other energy efficient car; reducing vehicles miles by using mass transit or biking; adopting a plant based diet, limiting consumption of goods & services, and foregoing air travel Cool Climate Calculator, C2ES, BBC, Our World in Data.

Although there is no single pathway to limit global warming to 1.5 or 2C SR15 p.109, most scenarios and strategies envision a major increase in the use of renewable energy in combination with increased energy efficiency measures to generate the needed greenhouse gas reductions Citation needed. They typically include some or all of the following elements:

• Overall Energy Systems - Renewable energy would become the dominant form of electricity generation, rising to 85% or more by 2050 in some scenarios. The use of electricity for other needs, such as heating, would rise to the point where electricity becomes the largest form of overall energy supply by 2050 UNEP Table ES.3, UTS Figure 5. Investment in coal would be eliminated and coal use nearly phased out by 2050; reductions in the use of other fossil fuel resources would follow a more gradual schedule SR15 Fig. 2.15 & p.131, Chapter 9.5 & Table 9.2.
• Transport - Transportation changes include a sharp increase in the market share of Electric Vehicles, low carbon fuel substitution for other transportation modes like shipping, and changes in transportation patterns to reduce overall demand, for example increased mass transit. SR 15 Ch.2.4.3.3, UNEP Table ES.3 & p.49, AR5 WG3 pp.72-74, Ch. 8.3.
• Buildings - Reductions in this category include decarbonizing energy use in buildings through additional electrification with the use of technologies like heat pumps, as well as energy efficiency improvements achieved via low energy building codes. AR5 WG3 p.23, pp.78-81, Ch. 9.3.
• Industry - Gains here can be realized by increasing the energy efficiency of production processes (such as the use of cleaner technology for cement production BBC 2018, designing and creating less energy intensive products, increasing the lifetime the products we produce, and developing incentives to reduce product demand. AR5 WG3 pp.81-85, Ch. 10.3, IRENA p. 49.
• Forestry & Agriculture - Carbon stocks in forests can be enhanced through reforestation/aforestation, sustainable forest management, and forest preservation. Enhanced soil carbon measures include uptake by using plant varieties that have deeper roots, agroforestry, adding organic materials to soil, and changing crop rotations AR5 WG3 pp. 86-89, Table TS.3, Ch. 11.3, NAP 2019 Table S.1, WRI 2019, SRCCL Ch.2.6.1.3 p 192.

Like with the technology section I edited the policies and measures section in line with the outline I posted. I moved some of the text from that section into the technologies section.

Policies and Measures

There are a number of legal and policy approaches used to reduce greenhouse gases. Carbon pricing mechanisms include carbon taxes and Emissions Trading systems UCS-Carbon Pricing. As of 2019, 57 national and subnational jurisdictions have instituted some form of carbon pricing. These mechanisms cover about 20% of global greenhouse gas emissions World Bank 2019 Box1 p.12. Phasing out of fossil fuels subsidies, currently estimated at $300 billion globally (about twice the level of renewable energy subsidies) REN2019 p.34, could reduce greenhouse gas emissions by 5-6% IISD. There are also proposals to swap fossil fuel subsidies for investments in renewable energy IISD. In terms of regulatory controls, adopting world class vehicle efficiency standards in G20 countries could reduce CO2 emissions by 50% ICCT p.iv. Regulatory measures to control air pollution, and related greenhouse gas reductions, are closely intertwined Commission 2010.

As the use of fossil fuels is reduced, there are Just Transition considerations involving the social and economic challenges that arise. One of the key concerns is the employment of workers in the affected industries, along with the well-being of the broader communities involved UTS-p.413. Climate justice considerations are also an important part of mitigation policies.

I created a new costs and benefits section, and added text in line with the outline I posted.

Costs and Benefits

The costs of achieving the greenhouse gas reductions necessary to limit global warming to 2C have a high degree of uncertainty, partly due to the ongoing reduction in the cost of renewable energy Fig. ES.5 p.XXIV, and difficulties with estimating other reduction costs LSE 2018. In 2019, the "One Earth Climate Model" showed how temperature increase can be limited to 1.5 °C for 1.7 trillion dollars a year OneEarth.

There are a number of environmental, economic and social co-benefts, as well as some adverse side effects, associated with limiting global warming AR5 WG3 Tables TS 4,5,6,7,8. The WHO estimates that meeting the goals of the Paris Agreement could save about a million lives a year worldwide by 2050 through reductions in air pollution alone. The overall air quality related health benefits were estimated to be approximately double the cost of greenhouse gas reduction at the global level; this benefit-to-cost ratio was even higher in countries such as China and India WHO 2018. Other studies support these estimates Sampedro 2020. IRENA estimates the overall global benefit-to-cost ratio at between 3:1 and 7:1 IRENA p.33.

Any suggested edits or other improvements would be much appreciated.Dtetta (talk) 19:34, 13 May 2020 (UTC)

Thanks for your hard work. I think this is too much in total, but maybe the sources blow it up visually. Don't have arms to give good feedback at all (RSI), but a few things:

Thanks @Femkemilene: for those suggestions. I am responding separately to each of your bullets.

@Femkemilene: I made several changes to address your comments. Please see individual responses below. I will be posting a full revision with references later today or tomorrow.Dtetta (talk) 22:42, 21 May 2020 (UTC)

• Technology section seems bloated, but most paragraphs are good. #1-First paragraph unsourced. #2-The bullet points partially repeat text above and don't add much in my opinion. #3-claim that policy is there to overcome barriers doesn't have cite.

I added numbers to your comment to facilitate a response. #1 I thought it was better to have wikilinks rather than citations in the first paragraph, as I think this information is somewhat common knowledge. But I can add cites if necessary. #2 I agree there is a little redundancy between the bullets and the technology/method descriptions, but mainly for the ag/forestry items. The objective was to describe the technologies/methods first, along with some discussion of merits/issues, and then to have the bullets reflect specific plans that are included in the major international organization reports on how these technologies/methods can be used/combined/implemented to get to the needed reduction goals. Specific suggestions on editing these bullets would be appreciated, but I think they are important and deserve coverage.#3 will add a cite.

Left the first paragraph as is for now. Changed the forestry bullet point to clarify and reduce redundancy. Added cite to policy barriers language.Dtetta (talk) 22:44, 21 May 2020 (UTC)

• regulatory control is jargon. I'm pretty sure vehicle efficiency standards don't reduce 50% of all CO2. Not sure just transition is sufficiently wide-spread to warrant inclusion in this top-level article. No cite for climate justice.

Revised the regulatory control language. Eliminated the 50% specific language. Added cite for climate justice.

Not sure what other words to use for the term “regulatory controls” (but coming from a regulatory background that might just be me), would welcome any suggestions for replacing the wording. I reviewed the ICCT reference, and their numbers seem to be well documented, but I will adjust the wording to leave out the specific 50% figure. I can eliminate the just transition sentence if needed, and will add a cite for climate justice.

Slightly revised the regulatory control language. Eliminated the 50% specific language. Added cite for climate justice.Dtetta (talk) 22:47, 21 May 2020 (UTC)

• subsections should never be in title case (Costs and benefits, not Costs and Benefits.)

Will make that change

DoneDtetta (talk) 22:49, 21 May 2020 (UTC)

• I'm not sure that section title is correct/sufficiently international. Papers related to climate change policy often state that C&B is only/mostly done in US/GB, but other countries often have a more broad policy appraisal method, which is multi-dimensional, instead of converting everything into one unit (money). As this section describes lifes saved, that doesn't fall under the Anglo-Saxon C&B analysis.. EU often talks more about risks, and sometimes opportunity.

Not sure how to respond on this. Key references here include IPCC, UNEP and WHO which seems pretty international to me. I agree there are more nuanced/complete ways of describing these issues, but was also striving for brevity. I think the WHO report on lives saved, and associated economic valuation, is a powerful way of making the point about what the minimum level of benefits is. Realize you are busy, but again, specific suggestions would be helpful when you have a chance.

I edited some of the language and references here, but could not find any guidance related to significantly different kinds of analyses used in the EU. I see that a recent EU climate change draft study seems to use pretty traditional C/B wording.Dtetta (talk) 22:52, 21 May 2020 (UTC)

• We don't cite any academic papers now, which will be a problem when we submit to a Wikijournal. The old version was significantly better in that aspect.

I can rework to include a larger percent of academic citations, but I have a concern with this. I no longer have the access to academic journals that I used to, and personally, I feel somewhat hoodwinked when I click on a WP link that takes me to an abstract only academic website that requires a subscription for the full article. I don’t think this is consistent with the WP mission to “to empower and engage people around the world to collect and develop educational content under a free license or in the public domain”. I imagine this issue has come up before, but I would suggest the following for academic cites that link to abstract only versions. In the footnote, include a short statement saying either “abstract only, full article available at: (location of free version of paper)”, or “abstract only: subscription required for full access”. This may not be needed if the abstract fully supports the statement in the WP article text, but my experience is that is often not the case. Very interested in other perspectives on this...did not see any specific WP guidance.

I added four academic papers -Berrill, Moorthy, Oh, and Gillingham. Kept Sampedro and Rauner. These are in the references section associated with the revised text. I thought Bednar and Hagmann didn’t seem to support the current texts they are associated with, and I couldn’t figure out a useful spot for them. Bertram would make sense if the text got into a more detailed discussion of policy approaches and their costs, but I couldn’t see a way of getting it to fit with the text I wrote.Dtetta (talk) 22:55, 21 May 2020 (UTC)

I was able to put Bertram at the end of the policies section as an example of a combined pricing/subsidiy/control approach.Dtetta (talk) 12:48, 22 May 2020 (UTC)

• The sentence "other studies support these estimates" can be dropped, by not using in text attribution. Facts don't always need attribution. This is edge-case. Femke Nijsse (talk) 12:54, 14 May 2020 (UTC)

I included the Sampedro reference because it is in the current version of the article, I but can delete that sentence.Dtetta (talk) 18:46, 14 May 2020 (UTC)

Hello Dtetta

I see you have been working hard on this. I have several comments - both positive and negative:

Thanks for those helpful suggestions Chidgk1!...My responses are below.

Chidgk1, I noted the further edits I have made in response to your comments below. I will be posting a full revised text later today.Dtetta (talk) 13:10, 22 May 2020 (UTC)

"Mitigation" and "Costs and benefits" sections

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I am struggling with the economics so I asked for help from the economics project but no reply so far. I now think my previous criticism was wrong and agree with you that subsidies for RE should stay in the article for now - as 2020 is so volatile I guess we will not know for sure until RE auctions next year or the year after whether RE subsidies are still needed. Without the help of an economics expert I am against adding that 1.5C could cost 1.7 trillion a year without any estimate of the benefits to balance it. Re 2C economics unless we can get the help of someone who really knows economics I think the text should stay as it is now. My understanding was that 2C benefits had already been proved to exceed costs - but not being an expert whether new info from 2020 changes that I have no idea.

I am certainly not an econ expert, so I was looking for sources/reports that seem well researched. I took the OneEarth report reference from the full Climate Mitigation article, where it seems to be the main cost reference. The other reference i had considered is AR5 WG3 Table TS2, which references a wide range of 2030 and 2050 costs. Another option would be to just qualitatively describe the types of costs involved, without putting a specific monetary figure on them. Happy to consider other options as well. When you say the 2C economics text should stay as is, are you just referring to keeping the statement associated with the Sampedro cite “globally the benefits of keeping warming under 2 °C exceed the costs”, or are there other statements you think should stay?

Added a wiki link to Economics of global warming based on your earlier comments.I did not see a good way of adding to the RE subsidies text, so was not able to incorporate the information on this that you had mentioned in an earlier comment.Dtetta (talk) 13:10, 22 May 2020 (UTC)

Technology

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I added numbering to the para. below to facilitate the response.

Hedgehoque has a point about this being before policies - so I withdraw my suggestion. #1-Re CCS I feel strongly that "fossil fuel power plants" is out of date and should be replaced so the sentence should read something like "Carbon capture and storage is a method of reducing CO2 emissions from heavy industry. CCS is a three-step process that includes: capture of CO2 from point sources such as chemical plants, transport of the captured and compressed CO2 (usually in pipelines), and injection of the CO2 in deep underground rock formations. (if you need a cite I can likely find one from UKCCC) #2-And I think the sentence following that should be removed as out of date and too negative. #3-Hydrogen is now important enough to have a link in my opinion. If you like I can draft a sentence or clause. For example we don't know yet how the split between heat pumps and hydrogen boilers will turn out, or whether big ships will be hydrogen or ammonia or electric or hybrid. #4-Are you sure the statement implying that the world can still burn a fair amount of oil and natural gas after 2050 is right? Maybe I should dig into the cites as it seems implausible, certainly for oil?

Re:#1 - Understand, I will change the language to what you propose. Re:#2 - Not sure I agree, but I am ok with deleting that language. Re:#3 - If you could suggest some language on hydrogen I would appreciate it. Re:#4 - I think you are referring to the “Overall energy systems” bullet, and the statements and associated cites at UNEP Table ES.3, & UTS Figure 5, correct? I did not attempt to verify those statements other than to note there seemed to be a good amount of research behind them. When I look at similar statements from AR5 WG3 I note that they are assuming increased carbon capture in the ag/forestry sector, or implementation of some level of CCS by 2050. Long way of saying that: no, I am not sure, but am going with what the major reports on this seem to state. Let me know if you have a different take on what those three reports are saying. It's not exactly the same message amongst the three, but it seems fairly consistent.

Changed the CCS language to what you proposed. I ended up finding some more neutral language to describe the barriers and limits to CCS, and included a very recent study that demonstrates its potential. I thought some description of the barriers associated with it was appropriate from an NPOV point of view. Have not gotten hydrogen language from you, and in looking at the SR 15 and REN21 reports, it seems that hydrogen from renewable resources is not considered a viable technology at this point, at least not in the same sense that the other technologies in this section are. So I did not add any language on renewably derived hydrogen fuels.Dtetta (talk) 13:10, 22 May 2020 (UTC)

Policies and measures

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I disagree with Femkemilene and think a link to "just transition" is important enough to be included. Because as I understand it the lack of it is often what causes policies to fail (e.g. Iran subsidy reform) and having it causes them to succeed (e.g. Germans paying lots of money to coal regions for phase out).

Good argument for keeping "just transition" in...let’s wait to see if Femkemilene has any additional insights on this.

Cites

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Re your discussion would it make sense if a cite (e.g. academic) is behind a paywall to have that and also a non-paywall cite too? Or would that be too much work?

That is a good option. It would actually be nice to have a WP policy on this. I went through the first 20 of the academic cites and saw restrictions on a little less than half, mostly Science, Nature, and Nature Climate Change. For the few academic cites I have done elsewhere in the article I have included url’s that go to free versions of the paper, and have been able to find free versions most of the time even for citations from the three periodicals I mentioned above.

Info in current version which is not in new

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There seems to be some useful stuff in the current version which is not in the new - I can make a list if you like. Chidgk1 (talk) 15:00, 15 May 2020 (UTC)

That would be great - I was trying to keep as much of the original as I thought worked in this version, so I would appreciate it if you could list the items you think I left out inappropriately. Dtetta (talk) 04:14, 16 May 2020 (UTC)

I brought in more text from the current version into the introductory paragraph and into the policies section.Dtetta (talk) 13:10, 22 May 2020 (UTC)

Hello Dtetta,

unfortunately my impression is that the condensed current version provides a better reading and straightforward flow of thoughts. For my understanding, the central issue in the technology section is: Wind and solar are becoming competitive enough to outcompete fossil fuels but require storage and large-area-grids. This is the currently the main obstacle. If we extend the length, I would rather add some dimensions: Which storage concepts are being discussed? What is the potential of grids? How can a combination of wind/solar/biomass/load management work? Which area for solar PV farms would be needed for 100% primary energy (roughly 1000 x 1000 km total)? Which capability would be needed for a global grid to minimize storage requirements (speaking of Terawatts)? Another issue is the low efficiency of Power-To-X. What would be a fair carbon tax compensating the damages (suggested 180-560 €/tCO₂)? And I am not happy with a C&B section though I can understand the motivation. However, these estimations, even if scientific, are extremely complex and almost impossible. The proposed new structure would be fine though. Hedgehoque (talk) 19:59, 19 May 2020 (UTC)

Thanks for that feedback Hedgehoque - I am assuming your concerns are about the paragraphs describing technologies, as opposed to concerns with the later paragraphs referencing the IPCC, UNEP and One Earth studies and dealing with how RE and other methods could specifically be implemented to meet 2050 targets. Please let me know if I’m wrong on this point.

I think I understand your point about the current text being more focused on the issue of wind and solar now being competitive enough to outcompete fossil fuels, but needing storage and large area grids. But I disagree that this concept should be the main focus of the section, mainly because of NPOV concerns, but also from the standpoint of helping an average reader get familiar with what the available technologies are.

Here are my main concerns with the current section (with apologies to whomever the author is): 1)There is no introductory paragraph for a general reader as to what mitigation technologies, including wind and solar, are available. I think the opening paragraph assumes a level of reader sophistication that may not be there for many people. 2)The sentences vary from supportive, in the case of solar and wind, to somewhat negative, in the case of bioenergy, to neutral in the case of energy efficiency. To me this presents both NPOV issues as well as clarity or writing problems. Re: NPOV, i would think that biofuels, nuclear energy, and CCS supporters would object to the one sided nature of the sentences describing those technologies, while a number of conservation groups like WRI or IUCN would contend that reforestation and regenerative agriculture deserve more complete and positive coverage, given how solar/wind are described. In fact, I think even my proposed text falls short in this regard, as I was trying to match the positive RE focus of the current text. From a clarity of writing perspective, those tone differences in describing the different technologies are confusing, and make the paragraphs seem disjointed. For me this current ”flow of thoughts” is actually very confusing. 3)The SuperGrid reference, while interesting, seems to be a somewhat futuristic concept, perhaps one of several others that could be mentioned. I would think distributed grids are a more “ready for prime time” item to be discussing here, for example. 4)Food waste is included as along with deforestation, which strikes me as a non sequiter. 5)There are a couple of other concerns, but I think you get my point. These are things I was trying to correct in the technologies paragraphs that I wrote.

I can see that in my original outline I wasn’t very clear on what I was proposing to write on the principal mitigation technologies. So here is what I think should be covered, and what was guiding me when I wrote the text.

• • Briefly mention the principal mitigation technologies available.
  • Describe what they’re able to do in terms of either moving us away from fossil fuel usage, lowering GHG emissions, or lowering GHG concentrations.
  • Describe their downsides and potential barriers to their usage, and briefly mention measures that can minimize those downsides.
  • Give each option relatively equal treatment.

I’m sure I was not completely successful in this, but those were the features I was striving for.

Also, I moved the footprint-related text to the technologies section because I think of it as more a measure/action that can be taken, like like stopping deforestation, or eliminating food waste (or putting solar on your roof/purchasing green energy, which should probably be added to the footprint list). From this perspective it really does not fit in the the policies section it’s currently in.

I’m close to having a next draft, with improved citations, ready to post to this page, but am concerned about your comments. I’d like to know your opinion of the concepts above that I suggested to guide the structure of the paragraphs (brief general intro, potential of each tech, downsides/barriers), as well as the principle of equal treatment. That might help me figure out a solution that might work for you. Look forward to your response.Dtetta (talk) 14:32, 20 May 2020 (UTC)

Dtetta, I understand your thoughts and you spent hours checking all these sources. I would have no problem if you add some aspects. I like the bullet points. But the main text – if approved by the community – should be straightened. With the honourable approach to be as NPOV as possible, the reader will end up confused with the impression that there are all sorts of approaches without getting a clue what could really make a change. I cannot see any alternative to rapidly scale up wind and solar installations in order to substitute fossil fuels. Nuclear power is risky and expensive for new installations, CCS could just help to gain some time. Biofuels land-use is 30-200 times less efficient (see Cleantechnica). Reforestation is good, but it does not fight the cause, just the symptom. So there is reason to have PV and wind in focus. How else could you ever produce the required annual 160 PWh of primary energy? Technologies are ready. You mention OneEarth. If you read the 100% RE article you can get an idea of what I mean. I wonder about their 1.7 trillion $ estimation though – per year how long? PV panels producing 320 PWh/year (the double world energy demand) would cost 5 trillion $ at current prices. Build a super grid for another 5T$ and we're done :-) Super grids are less futuristic than it might seem. Low-loss HVDC is developing rapidly – take a look at China. I would like to start with extensions there and the key question how to balance production and demand with these fluctuating sources. Hydrogen should be added. And at least a short mention that storage means loss in efficiency – leaving only 30% of the energy after reconversation in some cases. My (bold) approach to add some details about all of this was rejected some while ago - so maybe I am a bit sensitive about extending the text without really adding condensed, additional information... Hedgehoque (talk) 21:26, 21 May 2020 (UTC)

Thanks Hedgehoque. You make some good points here, I am just not sure how to resolve them. What I think I will do is put the next version of the text below and note in the Technologies section your concerns and my perspective on them, in italics just above the text, and ask for feedback from other editors. Please add any comments you feel are necessary to clarify how I presented the issue.Dtetta (talk) 13:23, 22 May 2020 (UTC)

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@Femkemilene: , @Hedgehoque:, and Chidgk1: Below is the next version of the text. I tried to address as many comments as possible, but I imagine I missed some things. Would appreciate folks giving this another review. I added proper citations/footnotes and a list of references at the bottom to aid your review. The references that are not in the current article are indicated with a + sign after the bullet. Current word count is around 1370, I believe.

@Femkemilene: - thanks for the thoughtful comments and kind words that you provided below. I was going to wait a couple of days to see if @Hedgehoque:, @Chidgk1: or any other editors had any additional comments to make, and then make edits. I provided individual responses to your comments below. I was also going to do an underline / strikeout of the text in each section to address everyone's comments. I’ll put a ✅ next to comments I think I have addressed. As a first step, both you and Hedgehoque have expressed ongoing concern with the length of the text in the technologies section, so that’s probably the first thing I will work on. As I asked Hedgehoque, I would ask you to let me know your thoughts on whether the technologies section should cover at least the following: 1)briefly mention the principal technologies available; describe their potential to move us away from fossil fuel usage, otherwise lower GHG emissions, or lower GHG concentrations; 2)describe their downsides and potential barriers to their usage (and means to mitigate them); and 3)give each option relatively equal treatment. Dtetta (talk) 22:43, 24 May 2020 (UTC)

MitigationV2

Climate change can be mitigated by reducing greenhouse gas emissions or by enhancing the capacity of carbon sinks to absorb greenhouse gases from the atmosphere. In order to limit global warming to less than 1.5°C with a high likelihood of success, the IPCC estimates that global GHG emissions will need to be net zero by 2050 , or by 2070 with a 2°C target. This will require far-reaching, systemIc changes on an unprecedented scale in energy, land, cities, transport, buildings, and industry:. To make progress towards that goal, UNEP estimates that, within the next decade, countries will need to triple the amount of reductions they have committed to in their current Paris agreements .

Technologies, and nature based methods, and individual actionsV2

Currently there are different perspectives on how this portion to the text should read. Hedgehoque would prefer briefer, more focused text that clearly indicates that solar/wind are really the only viable approach for achieving the needed GHG reductions. I think the text, while it can use facts to point out the advances made in solar/wind, should provide a relatively equal treatment of the different technologies, and provide a brief general intro, the potential of each tech, and the downsides/barriers. I am not sure how to resolve this, and would very much appreciate any thoughts on how this could be resolved.

Made a number of edits today in strikeout/underline format to this section.Dtetta (talk) 20:22, 27 May 2020 (UTC)

@Femkemilene:, @Hedgehoque:, and @Dtetta: I believe I have finished addressing people’s comments on the technologies/nature based methods section, and have shortened it as much as makes sense to me. It’s worth noting that the section does not mention energy efficiency technologies, and that is a flaw. But probably best to save for another day. Please let me know if you have any additional suggested edits.Dtetta (talk) 21:17, 31 May 2020 (UTC)

Removed the underline/strikeout so that interested folks could read the proposed text a little easier.Dtetta (talk) 00:22, 2 June 2020 (UTC)

Thanks for those edits yesterday and today @Femkemilene:. The 2% figure was referring to wind and solar only, so the sentence should have referred to just wind and solar to be consistent. But the future scenarios references I cite later seem to either be silent on the specific amount of wind and solar in 2050 (UNEP), or include a sizable role for geothermal and biomass (Teske). So the 11% figure may be a more realistic baseline to cite. Regarding eliminating the sentence describing institutional, regulatory and financial barriers, that’s probably a reasonable choice to focus on if there is a need to shorten, as it’s an additional concept that does not fit as well with the rest of the paragraph - I could have done a better job writing it. I included the sentence to address an earlier comment by @Hedgehoque: posted on May 7, which mentioned that these types of barriers were an important aspect to include. So I would be interested in his thoughts as well on eliminating it. If you are looking to further shorten the section, please consider ways of summarizing sentences rather than eliminating, and in your comments it would be helpful to know why you thought a particular edit was appropriate, aside from the general goal of shortening the article, specifically how did a given edit improve it? If the goal is to shorten the article, there are several other paragraphs in other topics and sections that could benefit from edits that focus on more concise, plain english wording.Dtetta (talk) 18:07, 19 June 2020 (UTC)

I will further specify edit summaries in the future. I'm done shortening the section now. I don't see big possibilities to shorten other sections; only 'nature and wildlife' and 'adaptation' could use, say, a 20% increase. If you think I made a mistake, please re-add the word(s). Femke Nijsse (talk) 09:26, 22 June 2020 (UTC)

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Long-term scenarios all point to rapid and significant investment in renewable energy and energy efficiency as key to reducing GHG emissions. These technologies include solar and wind power, bioenergy, geothermal energy, and hydroelectricity. Combined, they are capable of supplying several times the world’s current energy needs. Solar PV and wind, in particular, have seen substantial growth and progress over the last few years, such that they are currently among the cheapest sources of new power generation. Renewables represented 75% of all new electricity generation installed in 2019, with solar and wind constituting nearly all of that amount. . However, fossil fuels continue to dominate world energy supplies. In 2017 fossil fuels produced 79% of the world’s energy, with "modern" renewable sources, including solar PV and wind power, accounting for around 2%.

There are obstacles to the rapid development of renewable energy. Environmental and land use concerns are sometimes associated with large solar, wind and hydropower projects. Solar and wind power also require energy storage systems and other modifications to the electricity grid to operate effectively, although several storage technologies are now emerging to supplement the traditional use of pumped water/hydroelectric power. The use of rare metals and other hazardous materials has also been raised as a concern with solar power. The use of bioenergy is often not carbon neutral, and may have negative consequences for food security, largely due to the amount of land required compared to other renewable energy options. There are also institutional, regulatory, financial and social barriers involved in significantly increasing renewable energy supplies,, but a variety of policies and programs can be developed to overcome them..

For certain energy supply needs, as well as specific CO2 intensive heavy industries, carbon capture and storage may be a viable method of reducing CO₂ emissions. Although ongoing high costs have been a concern with this technology, recent work indicates that, by mid-century, it may be able able to play a significant role in limiting atmospheric CO₂ concentrations.

Greenhouse gas emissions can be offset by enhancing earth’s land carbon sink to sequester significantly larger amounts of CO₂ beyond current naturally occurring levels. . Forest preservation, reforestation and tree planting on non-forest lands are considered the most effective forestry methods, although they present sustainability and food security concerns. Soil management on croplands and grasslands is another effective mitigation technique. For all these approaches there remain large scientific uncertainties with implementing them on a global scale.

Individuals can also take actions to reduce their carbon footprint. These include: driving an EV or other energy efficient car and reducing vehicles miles by using mass transit or biking; adopting a plant based diet; reducing energy use in the home; limiting consumption of goods and services; and foregoing air travel.

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Still I believe it to be too much, completely out of balance with the adaptation section. Did small ce, can you do rest + other sections?.

Forgetting the individual actions paragraph, which is just relocated from another section in the original article, this text now has about 400 words, compared to about 200 for the current text for this section.Dtetta (talk) 02:24, 2 June 2020 (UTC)

I'm not sure whether I can get you on board with deleting major points, so I'm making smaller suggestions. Again RSI, so I should shut up, but addicted.

Made a number of edits today, ✅ indicates those where I think I have addressed your comments. Dtetta (talk) 20:22, 27 May 2020 (UTC)

Edited forestry/soil management paragraph, and believe I have now shortened the text in this section as much as makes sense. Please let me know your thoughts when you have a chance. ✅Dtetta (talk) 21:09, 31 May 2020 (UTC)

Re the first sentence, two thoughts: 1) As I mentioned, I will work on editing for brevity, as Hedgehoque also thinks this section is too long. But I would appreciate your input on the issue I mention in the italicized text at the beginning of the section dealing with what the text, at a minimum, should cover. ✅ - made a number of edits that included significantly shortening the section. Dtetta (talk) 20:25, 27 May 2020 (UTC) 2) I’m not convinced that the comparison itself is justification for shortening this section; I could interpret it just as easily as justification for expanding/strengthening the adaptation section. Re: second and third sentences - not sure what you mean, could you restate?

(edit conflict) Second: I did a small copy-edit, could you do the rest. Specifically, make sure to bundle short-cites (there should be only one number after each full stop/comma), put the refs after the full stop/comma, write CO₂ instead of CO2.

Will do.Dtetta (talk) 21:20, 28 May 2020 (UTC)

Third: I have tried to not ask very big changes, as I'm not not owning this article. I would like the article to stay manageable (or at least what I consider manageably small), but I'm easy going if the rest agrees.

• I love you have language skills. Jealous.

Thanks:) Took me a long time!

• remove individual action from title

Will do.✅

• REN21 does not say 10% renewable, but 10% modern renewable. Traditional biomass is big still.

Good point. Will revise accordingly.✅

• Phys.org is referring to a primary source, a single study. I'd rather not have it unless it's clear that this is the scientific consensus position. If we keep it, make it singular.

Agree - that was a bit rushed. Will check for corroborative studies, and if not make the language reflect the fact that it’s just one study.

Added a further citation supporting this.✅Dtetta (talk) 23:40, 27 May 2020 (UTC)

The statement about whether CCS will be viable on a big scale is a controversial one and open question. These popular science blogs are the lowest type of sources we're allowed, but I think this statement could use a secondary science source (review paper, discussion part of normal paper, report..). Your sentence seems to imply (to me at least) that support may have increased recently, and I'm not sure that's true. I think the recent work part can be remove entirely, or it will need better sourcing. The new source is mostly about techniques that aren't mature enough for big roll-out. Femke Nijsse (talk) 19:51, 28 May 2020 (UTC)

Understand. Will continue to look for more high quality sources, and revise the text accordingly.Dtetta (talk) 21:16, 28 May 2020 (UTC)

I edited the language of the paragraph slightly, and added the Bui reference, which indicates on page 1068 that that IAMs used in the IPCC SR 15 reports show significant CCS usage by mid-century in the both the 1.5C and 2C scenarios (something that seems to be hard to discern from the IPCC reports themselves). I kept the term “work” to reflect both the modeling information cited by Bui as well as the capacity and progress information included in the Zahasky study, but would welcome specific suggestions on better wording. I changed the article from Phys.org to ScienceDaily because ScienceDaily actually has a link to the Zahasky study, but describes the results in a more understandable way than the actual research article.✅Dtetta (talk) 02:46, 31 May 2020 (UTC)

Not sure that support has significantly increased; I did read a couple of articles on this, but I'm not convinced about their neutrality. I think some of these papers have just clarified some specific facts and aspects that point to at least some role for it by mid century.Dtetta (talk) 03:07, 31 May 2020 (UTC)

• I've never like the individual action paragraph we've had, as it relies on newspapers instead of a high-quality thing, but that may be for another day.

Based on personal interactions, I think footprint awareness is something a lot of readers care about, so to me that makes it important. From my experience with footprint calculators, I’m guessing that by following the general recommends listed in this text, or the current version in the article, the average G20 household could easily reduce their footprint by 1/3 or more, which collectively is a huge amount..another reason it's important to keep.

That is the reason I've always kept it in.. Maybe I just don't like the sourcing and the fact we have collected sources (risking tiny OR by selecting those and not others) instead of having one overview source for individual action. Femke Nijsse (talk) 19:51, 28 May 2020 (UTC) I can understand that. I will look for some more academic references.Dtetta (talk) 22:21, 28 May 2020 (UTC)

✅ I changed the footprint citations to limit the web references to just one NY Times article. I also added an academic reference for further support the text.Dtetta (talk) 14:56, 31 May 2020 (UTC)

• The concern with rare metals isn't that they're hazardous right? They are rare and their extraction can be pollution. Didn't read source.

Unfortunately, the concern is also that there will be major hazardous waste problems associated with large scale solar panel deployment once they are beyond their useful life, in addition to the precious metal and related mining concerns. It seems like the text conveys that, but specific suggestions for improvement are appreciated.

I see. Today I've Learned. Femke Nijsse (talk) 19:51, 28 May 2020 (UTC)

• (usually in pipelines) is unnecessary detail. Femke Nijsse (talk) 18:42, 22 May 2020 (UTC)

Will delete. Dtetta (talk) 22:58, 24 May 2020 (UTC)✅

Hi Dtetta. It looks much better now after today’s edit. Bioenergy could have a remark on the much higher land-use compared to PV (see link before). I miss the reference to super grids. They are not in the focus of most discussions but technology is ready and has a large potential – see the references. What would you think about a short mention of the most important storage techniques (hydrogen, power-to-gas, power-to-heat, Li-On, pumped hydro and compressed air) and their efficiency losses? We could also add a sentence about the difference between CSP (advantage: storage for some hours, but more expensive) and PV. The nature based methods would be another caption for me. The „scenarios“ section mentions some important issues. I can also go with the policies and the modified C&B section. Btw I did not write that wind and solar are the „only viable approach“ but I cannot see any serious zero-emission scenario in the near future that comes without massively upscaling these.Hedgehoque (talk) 22:32, 27 May 2020 (UTC)

Glad you think it's an improvement,Hedgehoque, and I apologize for not accurately capturing your position in the introduction. I could not get the bioenergy link to work, but have found a few other articles that emphasize the same point, so I will edit to add that clause you requested. I will also work to include a mention of the storage techniques you've described. I think the CSP/PV idea may be a little detailed, given concerns about the length of the text. The only issue I see with adding a nature based methods stand-alone section is that it leaves the footprint reduction paragraph a little stranded.Dtetta (talk) 00:19, 28 May 2020 (UTC) ✅ did not get into detail re:efficiency losses due to need for brevity.Dtetta (talk) 21:44, 28 May 2020 (UTC)

Oh, sorry about the link. I have repaired it above. It refers to this UCSB release: Photovoltaics beat biofuels at converting sun's energy to miles driven. The access to the study seems to be restricted except for the abstract, charts and maps. Please allow one stylistic remark: Maybe you can find a better intro than There a a number of... for the policies - just like you have done for technologies. Hedgehoque (talk) 06:14, 28 May 2020 (UTC) I will also make the change in the policies section you are suggesting when I get to editing that section.Dtetta (talk) 19:41, 28 May 2020 (UTC)

@Dtetta: Sorry I have not looked at this article recently, basically because I want to spend the time on my specialist subject (the articles related to Turkey and the environment) because I don't think anyone else is going to spend very much time on them. Also improving a featured article like this takes a lot of brainpower because it is so great already thanks to you guys. When I need a break from working on my specialist subject I find it more relaxing to improve articles where the changes needed are pretty obvious and don't need lots of consultation. I probably should not have made my criticisms of your proposed change in the first place now I am not following up on what I said I would do. But at the time I did not realise before how time consuming it would be to get the specialist subject articles I am working on rated as "good". Of course my non-reply has absolutely nothing to do with the fact that now we are allowed out I realise I need to get my bike fixed :-) Chidgk1 (talk) 07:12, 1 June 2020 (UTC)

Understand @Chidgk1: Thanks for the helpful comments you have made.Dtetta (talk) 12:33, 2 June 2020 (UTC)

Scenarios and strategies for 2050V2

I added this heading to clarify that the following text is intended to show how the technologies and methods mentioned in the section above are packaged to arrive at overall scenarios that achieve the 1.5/2C goal.

I did an underline/strikeout edit today in response to comments.Dtetta (talk) 02:29, 4 June 2020 (UTC)

Converted the underline/strikeout text to plain text to aid in viewing in case anyone would like to comment before I post this section to the GW article.Dtetta (talk) 23:53, 6 June 2020 (UTC)

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Although there is no single pathway to limit global warming to 1.5 or 2C, most scenarios and strategies envision a major increase in the use of renewable energy in combination with increased energy efficiency measures to generate the needed greenhouse gas reductions. Forestry and agriculture components also include steps to reduce pressures on those ecosystems and enhance their carbon sequestration capabilities.

Renewable energy would become the dominant form of electricity generation, rising to 85% or more by 2050 in some scenarios. The use of electricity for other needs, such as heating, would rise to the point where electricity becomes the largest form of overall energy supply by 2050. Investment in coal would be eliminated and coal use nearly phased out by 2050.

In transport, scenarios envision sharp increases in the market share of Electric Vehicles, low carbon fuel substitution for other transportation modes like shipping, and changes in transportation patterns to reduce overall demand, for example increased mass transit. Buildings will see additional electrification with the use of technologies like heat pumps, as well as continued energy efficiency improvements achieved via low energy building codes. Industrial efforts will focus on increasing the energy efficiency of production processes, such as the use of cleaner technology for cement production, designing and creating less energy intensive products, increasing product lifetimes, and developing incentives to reduce product demand.

The agriculture/forestry sector faces a triple challenge of limiting overall GHG emissions, preventing further conversion of forests to agriculture land, and meeting future increases in world food demand. A suite of actions could reduce agriculture/forestry based greenhouse gas emissions by 66% from 2010 levels by reducing growth in demand for food and other agricultural products, increasing land productivity, protecting and restoring forests, and reducing GHG emissions from agricultural production.

Scenarios that limit global warming to 1.5°C generally project the large scale use of carbon dioxide removal methods to augment the greenhouse gas reduction approaches mentioned above.

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• Still think this subsection is waaay too big. I'd like all bullet points to be reduced to about 2 words in a single sentence. Femke Nijsse (talk) 11:18, 23 May 2020 (UTC)

Trying for a solution - please respond to the following. I am ok with reducing the size of this subsection, but I think it’s important that there be a specific heading for this part, and that the text do two things: 1) help readers understand what is the thinking of the leading international organizations (IPCC, UNEP) on this, i.e. what could a 1.5C or 2C compliant world look like in 2050 in terms of how energy is generated/used, and 2) help readers understand the gist of IPCC SR 15 - Ch.2 Figure 2.15 & Table 2.6, UNEP 2019 - Table ES.3, and One Earth - Figure 5 (and their related texts), which strike me as three of the most authoritative recent depictions of the 2050 future. Will try to make edits to shorten this section while still meeting those two goals. Please let me know if you agree/disagree with this approach, or have other thoughts/suggestions. Dtetta (talk) 23:10, 24 May 2020 (UTC) Another option migh be to reduce the cost/benefit subsection to one sentence and putting it in one of the other sections, as is now in the current version of the article.Dtetta (talk) 06:15, 4 June 2020 (UTC)

I agree it's really important, and that UNEP and IPCC are the most authorative sources (not familiar with One Earth, and link doesn't seem to work for me). I think I can live with a shortened version, and trust your judgement here on specifics. If it comes up in the FAR that the article is too long, I will start thinking about this again.

✅Unfortunately, in researching edits for this section, I came across a WRI/UNEP/World Bank 2019 report that provides what seems to be a more cogent assessment of how the ag/forestry sector might evolve by 2050 to meet GHG reduction targets. This led to an increase in the wording associated with that paragraph. I was able to make some text reductions elsewhere, but there is no significant reduction overall. I really believe this is the level of detail that should be in the main article. If there are concerns about overall article length, there are some other sections where I think text reductions are possible, and can make specific suggestions/edits if needed.Dtetta (talk) 02:29, 4 June 2020 (UTC)

Before shortening, you may want to include it as a new section in climate change mitigation. That article is a mess though :(. Femke Nijsse (talk) 15:13, 25 May 2020 (UTC)

Yes, I thought about editing climate change mitigation as first step, but it seemed too daunting. Based on what the this portion of the GW article ends up looking like, I will try to figure out how to do some constructive edits there. Dtetta (talk) 21:21, 27 May 2020 (UTC)

The One Earth Executive Summary is worth reading when you have a chance - it captures the gist of the various Teske references. https://link.springer.com/content/pdf/bfm%3A978-3-030-05843-2%2F1.pdf. Dtetta (talk) 22:45, 27 May 2020 (UTC)

Policies and MeasuresV2

Note: divestment from fossil fuel resources could also be mentioned here.

Converted the underline/strikeout text below to plain text (and made a couple of minor grammatical edits) to aid in viewing in case anyone would like to comment before I post this section to the GW article.Dtetta (talk) 00:09, 7 June 2020 (UTC)

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A wide range of policies, regulations and laws are being used to reduce greenhouse gases, and additional measures are actively being considered. Carbon pricing mechanisms include carbon taxes and emissions trading systems. As of 2019, 57 national and subnational jurisdictions have instituted some form of carbon pricing. These mechanisms cover about 20% of global greenhouse gas emissions. Renewable portfolio standards have been enacted in several countries to move utilities to increase the percentage of electricity they generate from renewable sources. Phasing out of fossil fuel subsidies, currently estimated at $300 billion globally (about twice the level of renewable energy subsidies), could reduce greenhouse gas emissions by 6%. Subsidies could also be redirected to support the transition to clean energy. More prescriptive methods that can reduce greenhouse gases include vehicle efficiency standards, renewable fuel standards, and air pollution regulations on heavy industry, which can also bring about greenhouse gas reductions.

As the use of fossil fuels is reduced, there are Just Transition considerations involving the social and economic challenges that arise. A prominent example is the employment of workers in the affected industries, along with the well-being of the broader communities involved. Climate justice considerations, such as those facing Indigenous populations in the Arctic, are another important aspect of mitigation policies.

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• ce: cites ofter full stops and commas.

Will edit accordingly.✅Dtetta (talk) 19:03, 4 June 2020 (UTC)

• ETS either fully capitalized or not. I prefer not.

Will edit.✅Dtetta (talk) 19:03, 4 June 2020 (UTC)

• Renewable portfolio standards are another approach to reducing fossil fuel use that has a market component. -> Don't understand, can leave out the words market component, as this is the less 'market-driven' approach / smart regulation approach?

Confused-need more info. If you take a look at the wikipedia entry, I think you’ll see that these standards work similarly to the way ETSs work. That’s all I’m trying to say in the sentence. Open to other ways of saying it. BTW, in California, these are seen as being more effective than the state’s ETS program in getting electric utilities to move away from fossil fuels. Suggestions for alternative wording appreciated

My reading (OR of course), is that it's less market-driven than ETS, because CCS is necessarily excluded from the mix. More importantly, we need a source if we wanna say it has a market-component. My opinion: All policies have a market component. Regulatory instruments often drive innovation, whereas price-controls (possibly including RTS) are possibly better for scale-up. If I understand correctly, it only works as a ETS if it is combined with energy credits.. It's annoying that this policy instrument has many different names; I was fully aware the EU was doing something like that, but because of the name I only associated it with the US, never linking the 20-20 (20% renewable energy in 2020 EU policy) with that term... To summarize, indeed leave out the marking component? Femke Nijsse (talk) 15:04, 25 May 2020 (UTC)

I’m fine with leaving out the marketing component - will look for another brief way to distinguish them.Dtetta (talk) 22:36, 25 May 2020 (UTC)✅Dtetta (talk) 19:03, 4 June 2020 (UTC)

• Technology controls -> jargon. Rephrase sentence without

Confused-need more info. Revised this once - I am trying to draw a distinction between the methods in this paragraph, which are prescriptive (you must do a,b or c), and the more “market based” methods in the first paragraph, which are seen as giving companies more flexibility as to how to reduce GHGs. Can you think of a better phrase that would draw out this distinction? I could just say “other methods”, but that doesn’t really capture the difference between the two approaches/paragraphs.

Okay, I think I see where you're coming from. Glancing from Market-based environmental policy instruments, it seems that regulatory instruments may be an appropriate term, which is more intuitive to me, but may have negative connotations in the US? Femke Nijsse (talk) 14:25, 25 May 2020 (UTC)

”Regulatory instruments” still seems like jargon. I think I will play with trying to describe them just like I explained them to you - as more prescriptive approaches.Dtetta (talk) 22:27, 25 May 2020 (UTC)✅Dtetta (talk) 19:03, 4 June 2020 (UTC)

• leave out the (although efficacy has been questioned) detail

Will do✅Dtetta (talk) 19:03, 4 June 2020 (UTC)

• (...) an effective measure -> Cite Mercure study (or other study)

Thanks for noticing that. My mistake, I had meant to include the Bertram cite, which is what that text is referring to, and which is in the list of references. I added that (currently showing as footnote #61) to the text yesterday.

For brevity, I deleted this sentence. Let me know if you'd like to keep it.Dtetta (talk) 19:03, 4 June 2020 (UTC)

• Climate justice -> give example?

Will do✅Dtetta (talk) 19:03, 4 June 2020 (UTC)

• For the sake of brevity, fossil fuel divestment shouldn't be mentioned I believe. Femke Nijsse (talk) 11:09, 23 May 2020 (UTC)

Sounds fine. Dtetta (talk) 23:26, 24 May 2020 (UTC)

Costs and benefitsV2

In the comments to the earlier version of this text, there were clear concerns about having this as a full section, and about the value of C/B analyses. It may be that this section will not be included in the final edit, and a simple sentence like the one at the end of the policies and measure section will be used. Thoughts on this would be helpful.

@Femkemilene: Given the concern that you’ve expressed about the C/B language, and concern about the overall length of the mitigation section (it looks like it’s gone from about 500 to about 1200 words), I’m wondering if it’s best to not include the C/B paragraphs below at this point. The text from previous version of the article had a clause at the end of the intro paragraph stating that “globally the benefits of keeping warming under 2 °C exceed the costs.” I was thinking we could just have a short sentence along those lines at the end of either the Strategies and scenarios section or the Policies and measures section. Thoughts on this?Dtetta (talk) 21:53, 8 June 2020 (UTC)

—————————————————————————-

Determining the costs and benefits of achieving the greenhouse gas reductions necessary to limit global warming to 2C have a high degree of uncertainty, partly due to the ongoing reduction in the cost of renewable energy , and difficulties in predicting other costs . The IPCC’s most recent overall estimates for limiting warming to 1.5 °C range from 1.38 to 3.25 trillion dollars annually through 2035 ; a recent estimate by the One Earth organization calculates the cost at $1.7 trillion per year .

There are a number of environmental, economic and social co-benefts, as well as some adverse side effects, associated with mitigating greenhouse gas emissions . Health benefits alone are estimated to exceed costs, with the WHO estimating that meeting Paris Agreement goals could save about a million lives a year worldwide by 2050 through reduced air pollution, with health benefits estimated to be double the costs.. Dtetta (talk) 17:37, 22 May 2020 (UTC)

————————————————————————————————————

• CBA analysis terminology still quite prominent. Costs -> investments? Benefits -> Opportunities?

Some concern-additonal info would be helpful - I can try some alternative wording, but would love to see any large scale, widely supported work that uses a significantly different approach. Again, the recent EC C/B study for their 2030 plan, and a related EC page, seem to be talking in pretty traditional c/b terms, so am curious about the justification for alternative language.

If you click the link to the actual EC document, you'll see it contains a multidimensional impact assessment instead. At one point, it talks about costs and opportunities (which implies a dynamical economy), not benefits (typically assumes a roughly static economy). The word investment is mentioned 10 times, whereas costs are only mentioned five times. In section C, you see that the impact assessment is multi-dimensional. The documents talks about path-dependence ("towards a more sustainable path"), which is also typical of a dynamical understanding of the economy. When the word benefit is mentioned, it's often 'plain english', isntead of the technichal meaning. If it's the technical meaning, it's mostly in the sense of co-benefits. Femke Nijsse (talk) 08:22, 25 May 2020 (UTC)

Thanks - I see what you’re talking about. Will work on revised language...I like the term “investments”, and will figure out how to restate “benefits”.Dtetta (talk) 13:33, 25 May 2020 (UTC)

• Definitely cut One Earth sentence. Falls within the previous range, and is single study.

Will do.

• with health benefits estimated to be double the costs. Pricing human lifes in quite Anglo-centric. EU has multidimensional way of looking at this, making this sentence somewhat riduculous. Cut clause after comma Femke Nijsse (talk) 11:16, 23 May 2020 (UTC)?

Will do, but please note previous EU study I mention, with seems to show a fairly traditional C/B approach. The clause doesn’t seem ridiculous to me. Dtetta (talk) 23:34, 24 May 2020 (UTC)

Sources

• IPCC (2018). "Summary for Policymakers" (PDF). IPCC SR15 2018. pp. 3–24.
• United Nations Environment Programme (2019). Emissions Gap Report 2019 (PDF). Nairobi. ISBN 978-92-807-3766-0.{{cite book}}: CS1 maint: location missing publisher (link)
• ++ Teske, Sven (2019). "Renewable Energy Resource Assessment". In Teske, Sven (ed.). Achieving the Paris Climate Agreement Goals. Springer International Publishing. pp. 161–173. doi:10.1007/978-3-030-05843-2_12. ISBN 9783030058432. {{cite book}}: |work= ignored (help)
• IPCC (2014). "Summary for Policymakers" (PDF). IPCC AR5 WG3 2014.

*++IEA (2019). World Energy Investment 2019 (Report). Paris. Retrieved 10 May 2020.{{cite report}}: CS1 maint: url-status (link)

• ++"New renewable energy capacity hit record levels in 2019". BBC. 26 April 2020. Retrieved 25 May 2020.{{cite web}}: CS1 maint: url-status (link)
• ++REN21 (2019). Renewables 2019 Global Status Report (PDF). Paris: REN 21 Secretariat. ISBN 978-3-9818911-7-1.{{cite book}}: CS1 maint: location (link) CS1 maint: location missing publisher (link) CS1 maint: numeric names: authors list (link)
• ++Berrill, P.; Arvesen, A.; et al. (2016). "Environmental impacts of high penetration renewable energy scenarios for Europe". Environmental Research Letters. 11 (1). Retrieved 15 May 2020.
• ++"Environmental Impacts of Renewable Energy Technologies". Union of Concerned Scientists. 5 March 2013. Retrieved 15 May 2020.{{cite web}}: CS1 maint: url-status (link)
• ++"Barriers to Renewable Energy Technologies". Union of Concerned Scientists. 20 December 2017. Retrieved 17 May 2020.{{cite web}}: CS1 maint: url-status (link)

• ++ Roberts, D. (20 September 2019). "Getting to 100% renewables requires cheap energy storage. But how cheap?". Vox. Retrieved 28 May 2020.{{cite web}}: CS1 maint: url-status (link)

• de Coninck, H.; Revi, A.; Babiker, M.; Bertoldi, P.; et al. (2018). "Chapter 4: Strengthening and Implementing the Global Response" (PDF). IPCC SR15 2018. pp. 313–443.

• ++Geyer, R.; Stoms, D.; Kallaos, J. (2013). "Spatially-Explicit Life Cycle Assessment of Sun-to-Wheels Transportation Pathways in the U.S." Environmental Science Technology. 47 (2): 1170–1176. doi:10.1021/es302959h. {{cite journal}}: Invalid |ref=harv (help)

• ++Moorthy, K.; Patwa, N.; Gupta, Y. (2019). "Breaking barriers in deployment of renewable energy". Heliyon. 5 (1). doi:10.1016/j.heliyon.2019.e01166. {{cite journal}}: Invalid |ref=harv (help)
• ++Global Energy Transformation: A Roadmap to 2050 (2019 edition) (PDF) (Report). IRENA. 2019. Retrieved 15 May 2020.

*++"Carbon Dioxide Capture and Sequestration: Overview". Environmental Protection Agency. 17 January 2017. Retrieved 15 May 2020.{{cite web}}: CS1 maint: url-status (link)

• ++Bui, M.; Adjiman, C.; Bardow, A. (2018). "Carbon capture and storage (CCS): the way forward". Energy & Environmental Science. 11 (5): 1062–1176. doi:10.1039/c7ee02342a. {{cite journal}}: Invalid |ref=harv (help)

• ++"World can likely capture and store enough carbon dioxide to meet climate targets". ScienceDaily. 21 May 2020. Retrieved 30 May 2020.{{cite web}}: CS1 maint: url-status (link)

• ++Levin, Kelly (8 August 2019). "How Effective Is Land At Removing Carbon Pollution? The IPCC Weighs In". World Resources institute. Retrieved 15 May 2020.{{cite web}}: CS1 maint: url-status (link)

• ++World Resources Institute (December 2019). Creating a Sustainable Food Future: A Menu of Solutions to Feed Nearly 10 Billion People by 2050 (PDF) (Report). Washington, DC. Retrieved 2 June 2020.{{cite report}}: CS1 maint: url-status (link)

• Jia, G.; Shevliakova, E.; Artaxo, P. E.; De Noblet-Ducoudré, N.; et al. (2019). "Chapter 2: Land-Climate Interactions" (PDF). IPCC SRCCL 2019. pp. 131–247.

*"Reducing Your Transportation Footprint". Center for Climate and Energy Solutions. Retrieved 18 December 2019.

• ++Ritchie, Hannah (24 January 2020). "You want to reduce the carbon footprint of your food? Focus on what you eat, not whether your food is local". Our World in Data. Retrieved 15 May 2020.{{cite web}}: CS1 maint: url-status (link)
• ++Borunda, Alejandra (11 June 2019). "How can city dwellers help with climate change? Buy less stuff". National Geographic.
• ++"Climate change: Should you fly, drive or take the train?". BBC. 24 August 2019.

• ++Albeck-Ripka, Livia (1 January 2020). "How to Reduce Your Carbon Footprint". New York TImes. Retrieved 31 May 2020.{{cite web}}: CS1 maint: url-status (link)

• ++Druckman, A.; Jackson, T. (2016). "Understanding Households as Drivers of Carbon Emissions". In Clift, R.; Druckman, A. (eds.). Taking Stock of Industrial Ecology. Springer, Cham. pp. 181–203. doi:10.1007/978-3-319-20571-7_9. ISBN 978-3-319-20571-7.

• Rogelj, J.; Shindell, D.; Jiang, K.; Fifta, S.; et al. (2018). "Chapter 2: Mitigation Pathways Compatible with 1.5°C in the Context of Sustainable Development" (PDF). IPCC SR15 2018. pp. 93–174.
• ++Teske, Sven, ed. (2019). "Executive Summary". Achieving the Paris Climate Agreement Goals: Global and Regional 100% Renewable Energy Scenarios with Non-energy GHG Pathways for +1.5 °C and +2 °C. Springer International Publishing. pp. xiii–xxxv. doi:10.1007/978-3-030-05843-2_12. ISBN 9783030058432.
• Rogelj, J.; Shindell, D.; Jiang, K.; Fifta, S.; et al. (2018). "Chapter 2: Mitigation Pathways Compatible with 1.5°C in the Context of Sustainable Development" (PDF). IPCC SR15 2018. pp. 93–174.
• ++Teske, Sven (2019). "Trajectories for a Just Transition of the Fossil Fuel Industry". In Teske, Sven (ed.). Achieving the Paris Climate Agreement Goals. Springer International Publishing. pp. 403–411. doi:10.1007/978-3-030-05843-2_12. ISBN 9783030058432. {{cite book}}: |work= ignored (help)
• ++Creutzig, F.; Cruz-Núñez, X.; D’Agosto, M.; Dimitriu, D.; et al. (2014). "Chapter 8: Transport" (PDF). IPCC AR5 WG3 2014.
• ++Lucon, O.; Ürge-Vorsatz, D.; Ahmed, A.; Akbari, H.; et al. (2014). "Chapter 9: Buildings" (PDF). IPCC AR5 WG3 2014.
• Rodgers, Lucy (17 December 2018). "Climate change: The massive CO2 emitter you may not know about". BBC. Archived from the original on 17 December 2018.
• ++Fischedick, M.; Roy, J.; Abdel-Aziz, A.; Acquaye, A.; et al. (2014). "Chapter 10: Industry" (PDF). IPCC AR5 WG3 2014.
• ++"Carbon Pricing 101". Union of Concerned Scientists. 8 January 2017. Retrieved 15 May 2020.{{cite web}}: CS1 maint: url-status (link)
• ++State and Trends of Carbon Pricing 2019 (PDF) (Report). Washington, DC: World Bank. June 2019. doi:10.1596/978-1-4648-1435-8.

• ++"State Renewable Portfolio Standards and Goals". National Conference of State Legislators. 17 April 2020. Retrieved 3 June 2020.{{cite web}}: CS1 maint: url-status (link)

• ++Ciucci, M. (February 2020). "Renewable Energy". European Parliament. Retrieved 3 June 2020.{{cite web}}: CS1 maint: url-status (link)

• Raising Ambition Through Fossil Fuel Subsidy Reform: Greenhouse gas emissions results modelling from 26 countries (PDF) (Report). Geneva: Global Subsidies Initiative of the International Institute for Sustainable Development. June 2019.
• ++Miller, J.; Du, L.; Kodjak, D. (2017). Impacts of World-Class Vehicle Efficiency and Emissions Regulations in Select G20 Countries (PDF) (Report). Washington, DC: The International Council on Clean Transportation.
• ++Schillaci, William (26 June 2019). "RFS Has Only a Small Impact on GHG Emissions". EHS Daily Advisor. Retrieved 15 May 2020.{{cite web}}: CS1 maint: url-status (link)

• ++Oh, I.; Yoo, W.; Yoo, Y. (2019). "Impact and Interactions of Policies for Mitigation of Air Pollutants and Greenhouse Gas Emissions in Korea". International Journal of Environmental Research Public Health. 16 (7): 1161. doi:10.3390/ijerph16071161. {{cite journal}}: Invalid |ref=harv (help)CS1 maint: unflagged free DOI (link)

• Bertram, Christoph; Luderer, Gunnar; Pietzcker, Robert C.; Schmid, Eva; Kriegler, Elmar; Edenhofer, Ottmar (2015). "Complementing carbon prices with technology policies to keep climate targets within reach". Nature Climate Change. 5 (3): 235–239. Bibcode:2015NatCC...5..235B. doi:10.1038/nclimate2514. ISSN 1758-6798.

• ++Yeo, Sophie (4 Jan 2017). "Clean energy: The challenge of achieving a 'just transition' for workers". Carbon Brief. Retrieved 18 May 2020.

• ++Tyson, Dj (3 October 2018). "This is What Climate Change Looks Like in Alaska—Right Now". Pacific Environment. Retrieved 3 June 2020.

• ++Ristroph, E. (2019). "Fulfilling Climate Justice And Government Obligations To Alaska Native Villages: What Is The Government Role?". William & Mary Environmental Law and Policy Review. 43 (2). {{cite journal}}: Invalid |ref=harv (help)

• ++Adams, B.; Luchsinger, G. (2009). Climate Justice for a Changing Planet: A Primer for Policy Makers and NGOs (PDF). UN Non-Governmental Liaison Service (NGLS). ISBN 978-92-1-101208-8.

• ++Gillingham, K.; Stock, J. (2018). "The Cost of Reducing Greenhouse Gas Emissions". Journal of Economic Perspectives. 32 (4): 53–72. doi:10.1257/jep.32.4.53. {{cite journal}}: Invalid |ref=harv (help)
• ++"How much will it cost to cut global greenhouse gas emissions?". London School of Economics and Political Science. 8 May 2018. Retrieved 18 May 2020.

• ++"One Earth Climate Model". One Earth Climate Model. University of Technology, Climate and Energy College, German Aerospace Center. Retrieved 15 May 2020.

• Edenhofer, O.; Pichs-Madruga, R.; Sokona, Y.; Kadner, S.; et al. (2014). "Technical Summary" (PDF). IPCC AR5 WG3 2014.

• ++"Health benefits far outweigh the costs of meeting climate change goals". World Health Organization. 5 December 2018. Retrieved 15 May 2020.
• Sampedro, Jon; Smith, Steven J.; Arto, Iñaki; González-Eguino, Mikel; et al. (2020). "Health co-benefits and mitigation costs as per the Paris Agreement under different technological pathways for energy supply". Environment International. 136: 105513. doi:10.1016/j.envint.2020.105513. ISSN 0160-4120. PMID 32006762.

• Rauner, Sebastian; Bauer, Nico; Dirnaichner, Alois; Van Dingenen, Rita; Mutel, Chris; Luderer, Gunnar (2020). "Coal-exit health and environmental damage reductions outweigh economic impacts". Nature Climate Change. 10 (4): 308–312. Bibcode:2020NatCC..10..308R. doi:10.1038/s41558-020-0728-x. ISSN 1758-6798.

Adding/Editing Graphics to the Section?

I had a question and suggestions about the current graphics in the Mitigation section. The first two (total and per capita fossil CO2 emissions) show emissions and trends of various countries. Is the purpose of this graphic to visually support the text in a tangential way by showing which countries most need to step up to limit GHGs? Mainly the last sentence of the intro paragraph in the Responses topic? They do take up a good bit of real estate, so I wanted be sure of the purpose of the two graphics.

Also, while I think the Emission pathways to Paris graphic has a lot of good information, I think there are other graphics that might better capture the essence of the main 2050 mitigation scenarios and overall messages in this section, and could also be included In the text. I would suggest adding graphics that distill/depict the messages in: IPCC SR 15 - Ch.2 Figure 2.15 & Table 2.6, UNEP 2019 - Table ES.3, and One Earth - Figure 5

Another thought would be to create an image gallery of mitigation methods like what Efbrazil created for the lede.

@RCraig09:, @Efbrazil:, and @Femkemilene: it would be great if you could share your thoughts on this. I am somewhat intimidated by the thought of trying create a graphic myself, and worry that even if I can get up to speed on doing this, I will end up spending a lot of time creating something that will end up being rejected.Dtetta (talk) 23:04, 4 June 2020 (UTC)

Dtetta, I think your three suggestions are interesting but a bit too detailed, especially Table ES.3, for a high-level article. I like the three current drawings because they instantly convey ideas to lay readers who constitute most WP readers. Consensus here seems to have placed a premium on formal matters such as image size, spacing and arrangement, at a cost to substantive visual content; in any event I do like the idea of image galleries or animated GIFs. —RCraig09 (talk) 04:36, 5 June 2020 (UTC)

Thanks @RCraig09: for the quick response. Yes those tables and charts would be difficult to distill for the lay reader. I’ve been trying to find something like the waterfall diagrams at: United in Science Page 12 and WRI Page 3 that would get to zero zero emissions on the right hand side. And I look at the preceding discussion about the causes and effects diagram as a real cautionary tale. I’ll take your advice and start by looking at ways of doing some sort of image gallery like EF Brazil did for GW/CC effects. Not sure if I have the technical skills but hope to give it a try.Dtetta (talk) 16:09, 5 June 2020 (UTC)

To avoid wasted time, you Dtetta may want to just list specific proposed images here—rather than the time-consuming job of generating images and assembling them into a gallery. —RCraig09 (talk) 16:28, 5 June 2020 (UTC)

Makes sense. I will look for some images (solar, wind, efficient buildings, forest preservation) once I finish the text edits.Dtetta (talk) 17:15, 5 June 2020 (UTC)

@Dtetta: I went through the figures you suggested Dtetta. In addition to creating graphics for a general audience, most of our viewers are on smartphones, so graphics really need to be legible at a thumbnail size, max upright=1.35, and need to be localizable (SVG with clear text that can be resized). That's the standard we've been following, and it's also a good standard to follow when you are simplifying a technical diagram for a general audience. If there's a key piece of information that's in these charts that you think needs to be elevated then we could take a crack at a new graphic. If information cannot be condensed, it might be better to surface the information as a table. Creating a mitigation pathways table that's sortable and allows people to click through to mitigation techniques could be worthwhile. The charts covering national responsibility and the waterfall charts covering sources and sinks are redundant with images already in the article, for instance File:Carbon_Sources_and_Sinks.svg and Global warming#Responses. Efbrazil (talk) 19:24, 5 June 2020 (UTC)

Thanks @Efbrazil: I’ll do some reading to try and understand the technical guidance you’re mentioning on graphics. I have not created any before for WP, so am at the low end of the curve. You last sentence leads me to think I wasn’t clear what I was proposing with the waterfall diagram. Not sure specifically which figures you are referring to when you say you went through the ones I suggested, but I am thinking of something that has the same format as the diagram on WRI Page 3 titled “The Emissions Gap”. But instead of those numbers, the bar values/lengths would be something like (starting on the left and going right): 52 Gt (for the current annual GHG emissions), then the estimated 2050 reductions for solar, wind, energy efficiency, a summary of some of the WRI reduction proposals, perhaps CCS, and maybe one or two others, with the bars leading to zero on the right hand side…similar to how WRI presents this in their diagram. To me that’s completely different than the two charts you linked to, both of which are depicting current conditions from different perspectives; I’m trying to summarize the “consensus” from the major international reports on how to get to NetZero. In addition to struggling with the horizontal sizing of all this, I wonder if the biggest issue/challenge is that there are a few different 2050 scenarios and sources of information, such that trying to create one chart is getting into OR territory.Dtetta (talk) 15:18, 6 June 2020 (UTC)

@Dtetta: Yeah, NetZero pathways are inevitably conjecture, but I think a table with some grounding in the current state would be good. Maybe the rows could be proposed solutions (solar, tree planting, nuclear, waste reduction, etc) and the columns could be percentage contributions from those technologies today, growth rates today, and then what an organization says they need to be at by 2050. Efbrazil (talk) 17:44, 14 June 2020 (UTC)

That makes sense @Efbrazil:. I will be working on some gallery show pictures first, and then see about how to compile data for the kind of graphic you are describing.Dtetta (talk) 03:01, 16 June 2020 (UTC)

Not to belabor the point, but I think a table makes more sense than a graphic. Tables allow for drilldown and are better for text, which this information will mostly be. See here: [1]. Something like this, except with real numbers and categories:

CO2-equivalent mitigation pathway	Current mitigation vs 2018 total CO2-equivalent emissions		Required contribution for 2050 Netzero initiative
	Percent of total	Rate of change	Target contribution	Required annual increase
solar energy	2.1%	+0.4	25%	+2.6
hydro energy	2.1%	+0.4	25%	+2.6
wind energy	2.1%	+0.4	25%	+2.6
nuclear power	2.1%	+0.4	25%	+2.6
energy use reductions	2.1%	+0.4	25%	+2.6
carbon capture	2.1%	+0.4	25%	+2.6
change in meat consumption	2.1%	+0.4	25%	+2.6
increased vegetation	2.1%	+0.4	25%	+2.6

Efbrazil (talk) 19:55, 18 June 2020 (UTC)

Well you have certainly done a lot of work in this area, so I will go with your suggestion. Thanks for doing all the coding for the table.Dtetta (talk) 00:23, 20 June 2020 (UTC)

@RCraig09: and @Efbrazil: I have found a few pictures from wikimedia on Solar farms, Wind farms, Energy Efficient Construction, and Carbon Capture and Storage. I was wondering if either of you could provide a suggestion for resources to help me get started developing a gallery from these images. I’m having a hard time following the code example of the gallery you created on this page. Thanks.Dtetta (talk) 22:30, 16 June 2020 (UTC)

Sorry, though I can generate charts, it was Efbrazil whose heroic techy efforts formed the slideshow. Since space is at a premium in this already-long article, I think slideshows or GIFs are a good space-saving solution in some spots. —RCraig09 (talk) 02:12, 17 June 2020 (UTC)

Thanks. And I should add that I have looked through the references for creating and posting images, as well as several images on the site, so I think I get the requirements for that, but it’s the image gallery coding that I can’t figure out.Dtetta (talk) 13:49, 17 June 2020 (UTC)

Citation standards

This standard should be reworded:

• k: Multiple authors: only the first five need be listed. If more than four set "|display-authors=" to 4.

This is an example of the confusion of a "requirement" and a "method". I believe the "requirement" is:

• k: Multiple authors: only the first four are displayed. ["Method":] If more than four use "|display-authors=4", or list four and use "|display-authors=etal"

Listing five (or more) authors and using |display-authors=4 implies all authors are listed and the display was shortened. Listing four authors and using |display-authors=etal shows that the author list was intentionally shortened.

There can be standards for methods. In which case I would propose the standard to be:

• k: Multiple authors: List all. If more than four set "|display-authors=4".

I assume this standard applies to editors as well, but … . --User-duck (talk) 17:35, 16 June 2020 (UTC)

Makes sense, feel free to edit as you see fit :). Femke Nijsse (talk) 18:46, 18 June 2020 (UTC)

Citation standards (<ref name=)

This standard confuses me:

• s: Use of named-refs (the "<ref name=" construct) to duplicate notes is discouraged.

I interpret this to mean that the desired coding is:

• Some prose. More prose. Some more prose.

In which case the standard should be reworded:

• s: Use of named-refs (the "<ref name=" construct) to reduce duplicate notes is discouraged.

The following standard might be misleading:

• n: In-line citation of content to be done with short-cites (such as done with {{harvnb}} templates or similar).

I think of the {{sfn}} templates as being "similar". But standard "s:" would discourage their use because they combine notes.

• Some prose. More prose. Some more prose.

Discouraging duplicate notes contradicts WP:DUPCITES. -- User-duck (talk) 18:29, 16 June 2020 (UTC)

Shall we just remove s then? DUPCITES is mostly about full citations I think, so doens't quite apply, but I'm happy to make the CITEVAR easier and more consistent, and I like duplicating notes. Femke Nijsse (talk) 10:52, 18 June 2020 (UTC)

References

"Bioenergy"

Hello, phrases such as "biofuel" are being used on this page as part of the solution for reversing global warming. It is misleading. "Biofuel", "biomass", "bioenergy", etc, are ideas for problems with scarcity, but they are not solutions for carbon output and climate change. The problem is not about burning fossil fuels... but it is about burning stuff, and biomass is stuff. Apologies... ~ R.T.G 16:04, 20 June 2020 (UTC)

I believe the current mitigation section as written recognizes that burning biomass may not be carbon neutral. The One Earth report (whose Ex Sum is cited as Teske) does envision bioenergy as having some role in achieving Net Zero conditions. So I think the current wording attempts to address the issue you are raising. More specific wording suggestions, with appropriate references, are welcome.Dtetta (talk) 17:25, 20 June 2020 (UTC)

Around the same time that the word "renewable" started to overtake the word "sustainable" in environmentalism, according to File:Total CO2 by Region.svg from this article, a great downward trend in carbon release started to revert back to an upward trend. Language is so significant. I'm not sure about the exact wording but here are some sources talking about a new awareness of biofuels, [2][3][4][5]. For one thing, biofuel can mean a whole lot of things. The one which was hoped to be a solution to global warming was the wood pellets. For any carbon released burning the fuels would be captured when trees regrow. But to achieve that regrowth, forests must first be cut down, and then replaced with plantation forestry... So to achieve a net reduction, enough forestry plantations have to be built both to make up the difference between forest and plantation carbon capture efficiency, and the worse-than-coal emissions profile. Apparently, all they have achieved so far is a net loss and an increasing disappointment. In terms of the article, the issue is basically confined to the "Technologies and other methods", and maybe it should just be altered so that instead of presenting "bio-x" as a solution, to present it as more of a nice but impracticable theory? ~ R.T.G 09:28, 22 June 2020 (UTC)

While interesting, this article is about mainstream science and we don't have enough space to go into detail about new (and therefore not established) science. The article is already quite negative about biomass, which I believe reflects the literature, and is possible even a tad bit more negative than the average literature. Specific adjustment + sources suggestions are welcome. Femke Nijsse (talk) 10:14, 22 June 2020 (UTC)

You think the effectiveness of biomass is not mainstream science... that the degree of negativity in the article has more correlation to, I don't know what, than relevance and fact..? I'm sorry Femke, I am disillusioned with this stuff too, but one fact is, biomass has not mitigated climate anything, and that fact has been in public knowledge, if not awareness, for a long time. There is no real advantage to being awkward about acknowledging it. ~ R.T.G 17:35, 22 June 2020 (UTC)

RTG, the theory is that biomass fuels are part of a short cycle, with carbon captured and released close to contemporaneously, as opposed to fossil fuels, which release carbon that was captured in the distant past. To claim that this is a scarcity issue is simply incorrect. The use of biodiesel, for example, is very clearly intended to address the need for net-zero. Guy (help!) 10:58, 23 June 2020 (UTC)

In practice, these forests do not appear by magic. They do not originate from this *new* carbon. What happens is, word goes out that we want to burn down significant amounts of trees. The big guns for pine trees are places like Canada, Russia, and California. So they cut the mature trees, real forests, which breathed way more than the lifeless plantation trees they are replaced with... And what you are starting with is not a new bonus, but a new deficit. A catch 22, never to be filled. Widely acknowledged.

Again, if you think biodiesel is like a net-zero solution... well, if it starts to get into *significant demand*, it isn't going to come from a magically empty place, like you were brought to believe... It is going to come from a place where there was a forest...

If you look at a chart of this stuff... you get all this bio/solar/wind stuff at the bottom of the chart with oil... and hydro electricity like 50 times higher up the chart... storage, production, whatever... Yet here on this article, for instance, hydro is portrayed as an accessory to the others. ~ R.T.G 17:17, 23 June 2020 (UTC)

Ready for copy-edit?

We've tackled all suggestions from the featured article review pre-review as far as I'm concerned, and also rewrote the mitigation section. Are we ready for a copy-edit before we ask for a proper FAR? Signing off for a few days. Femke Nijsse (talk) 16:10, 22 June 2020 (UTC)

I vote that we are ready for a copy-edit.Dtetta (talk) 19:22, 26 June 2020 (UTC)

I identified and rewrote a very weak subsubsection. Going to wait till to see if that new version is stable. Femke Nijsse (talk) 05:36, 27 June 2020 (UTC)

There isn't any real "see also" section. ~ R.T.G 20:25, 28 June 2020 (UTC)

That's fine, see WP:SEEALSO. Because the article is comprehensive, there aren't many internal links that haven't been mentioned in the body of the text. Femke Nijsse (talk) 08:40, 29 June 2020 (UTC)

Then I am going to take the liberty starting with global warming potential. ~ R.T.G 08:48, 29 June 2020 (UTC)

That has already been linked from the article (be it not using that jargon), so that one doesn't work. Per WP:ONEDOWN we shouldn't use any unnecessary jargon in this article. Femke Nijsse (talk) 09:22, 29 June 2020 (UTC)

I can't find it by searching the source text. ~ R.T.G 09:49, 29 June 2020 (UTC)

It's in this sentence: Global anthropogenic greenhouse gas emissions in 2018 excluding land use change were equivalent to 52 billion tonnes of carbon dioxide. Femke Nijsse (talk) 10:42, 29 June 2020 (UTC)

FYI at the time of this thread that sentence wikilinked to a redir; on account of htis thread I updated the wikilink to point to the target article, global warming potential. NewsAndEventsGuy (talk) 16:22, 3 July 2020 (UTC)

Milankovitch cycles

The article says " (IPCC) concluded that "human influence on climate has been the dominant cause of observed warming since the mid-20th century"..." ... but it doesn't mention any of the other influences. It should. ~ R.T.G 09:49, 29 June 2020 (UTC)

It does later in the article. In the summaries of our highest quality sources, it doesn't mention the other causes (because on average, about 100% is explained by GHG + antropogenic aerosols). Those sources don't mention the Milankovitch cycles, which play out over waaay longer time scales. So it would be undue weight to put it in our lede, which is already somewhat to long for an FA article. Femke Nijsse (talk) 14:38, 29 June 2020 (UTC)

I don't know what you are talking about regarding summaries of highest quality sources, however, what I can tell you is that the Milankovitch cycles are the only, and yet inclusive of the most significant, natural factors not characterised in some way by this article. ~ R.T.G 17:01, 29 June 2020 (UTC)

We have limited space, so we use summaries (often still 20-50 pages) of RSs to determine whether something is WP:DUE weight. As Milankovitch cycles are way too slow to cause global warming, they are often not included in these summaries. For instance: https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_SPM_FINAL.pdf. This (highest quality RS) document about the physical climate change doesn't mention milancovitch, so we shoudn't either. (we do mention orbital forcing as an example of radiate forcing btw). Femke Nijsse (talk) 17:46, 29 June 2020 (UTC)

If an item is relevant to a topic and published, we are supposed to cover it. We are not an extension of the IPCC, and their omissions have absolutely nothing to do with our inclusions. No, it doesn't "mention orbital forcing". The closest thing is a section called "Natural forcings" (?) which misguides the reader into believing the only natural factor which influences the temperature of the Earth is the Sun. I am finding myself compelled to find a way to note your attitude toward broad coverage as an apparently main contributor to this article, Femke. There is no way this article passes the good article criteria let alone FA, sorry. ~ R.T.G 18:44, 29 June 2020 (UTC)

In a top-level article, you can't put everything that is published. You have to determine due weight. The natural forcing section only mentions volcanoes once, and a case could be made that it should have more attention to that factor, as it is mentioned in summaries of RSs. Another example (NCA about drivers): https://science2017.globalchange.gov/downloads/CSSR_Ch2_Physical_Drivers.pdf. They only mention Milankovich once off-handedly in 41 pages about causes. If we summarize that in one page, an off-hand mention doesn't make the cut. I would be keener to listen to you if you would provide at least one source about global warming (a somewhat general source to determine DUEness) discussing Milancovich cycles. Femke Nijsse (talk) 19:32, 29 June 2020 (UTC)

Other appropriate policies: WP:SUMMARY (we shouldn't go into unnecessary detail) and WP:ONUS (verifiability isn't enough for inclusion) might be useful for you to read. Femke Nijsse (talk) 19:41, 29 June 2020 (UTC)

Avoiding unnecessary detail is not the same thing as opposing any detail at all! Invoking ONUS is ridiculous here. There is no uncertainty about what the Milankovitch cycles are. Without that knowledge, climate change cannot be understood no matter what your inadequate IPCC "policy" document is using. Climate cycles occur over hundreds of thousands of years. The only thing you are fostering with this is more disillusionment, more skepticism. This is not a guide to drafting policy. This is an encyclopaedia. You have to cover the climate cycles to some extent, and the sources and effects of the major greenhouse gasses at least, or it cannot be considered broad coverage. ~ R.T.G 21:41, 29 June 2020 (UTC)

Methane and nitrous oxide are insignificant

Another issue with the article regards human-activity based methane and nitrous oxide emissions. It has long been known that industrial farming is producing methane and nitrous oxide. According to this article, in 2018, 19% of greenhouse emissions was methane, and 6% nitrous oxide. But all greenhouse gases are not equal. The technical term is Global warming potential. According to our article for global warming potential, the effects of methane and nitrous mitigate over time:- In the first 20 years it is projected to be between 60 and 90x the effect with methane, and in the first 100 years of nitrous, 300x.

This article covers livestock with this:- "19% was methane, largely from livestock", and nothing more. This article uses the word "potential" 10 times, but not once to mention global warming potential. ~ R.T.G 22:06, 22 June 2020 (UTC)

RTG, sure, but we can't synthesise this. Do you have sources that make the point you want to reflect here? Guy (help!) 11:00, 23 June 2020 (UTC)

Jz, there are more than 25 sources on the Wikipedia article I linked. We are coming down with sources for this. Just search up various phrases like, "how much worse is methane than carbon" (without quotes). ~ R.T.G 17:21, 23 June 2020 (UTC)

I think a brief explanation of greenhouse gas potential would be a good addition, probably in the first or second paragraph of the greenhouse gases section. I can work on and post a proposed edit here if that would help.Dtetta (talk) 21:16, 26 June 2020 (UTC)

It's already in there; we chose to avoid the jargon and link it from the word equivalent. I'm not keen on introducing the jargon, but okay with slight expansion to explain it if you feel that would improve the section. Femke Nijsse (talk) 06:08, 27 June 2020 (UTC)

Sorry Femke, when I search the article for "methane" and "nitrous" there is absolutely nothing to point out that these are by far the most significant greenhouse gasses. Here is a perspective:- The word "nitrous" gets 2 hits on the page, not a single letter toward explaining its origins or significance. The word "methane" gets 10 hits including some in the references section, including one sentence about permafrost release, less than a sentence about livestock, and absolutely nothing describing the significance as a greenhouse gas. The word "carbon" gets over 100 hits. It's not about avoiding jargon at this stage. The significant aspects of methane and nitrous oxide are missing from this article. I can see it has had two FA reviews and that you are planning more work towards that effort, but it doesn't qualify as a featured article if it doesn't include this information. ~ R.T.G 19:24, 27 June 2020 (UTC)

@Dtetta: yes I for one am totally open to that. You will find that the exact figure is elusive, regarding how much more damaging these particular gasses are, but they are either directly above or below carbon gasses and they are widely accepted, and disputed to some extent, as extremely significant in the human aspect. I'm sorry for delaying and arguing, I'll try later on today to suggest some sources or something if that helps, thanks. ~ R.T.G 06:23, 30 June 2020 (UTC)

• Okay, to my surprise, after all of the hype about depleting ozone in the 80s and 90s, I looked at a source used on the articles "Public debate" section about ozone [6] and it is claiming that ozone in the lower atmosphere is on the increase because of nitrous and methane producing it as they break down. It claims that tropospheric ozone is responsible for 0.5 degrees temperature raise and shows a lot of detail about the historical prevalence and sources. The paper concludes that ", a greater role for tropospheric ozone in driving 20th-century climate change would improve agreement between the model and the observations..." i.e. that we seem to underestimate tropospheric ozones potential as a greenhouse gas... but our "Public debate" section is using that source and this source[7], which mentions "ozone" in only one sentence... to claim that we overestimate the effects of ozone depletion... and imply that the two should not be considered part of the same issue. It is confusing to say simply that ozone depletion and climate change are not linked. The release of HFC-23 alone, according to the IPCC[8], has contributed 14% to radiative forcing, and is being produced at a faster rate than ever before (despite claims according to the ozone depletion article, that the Montreal Protocol is the most successful environmental agreement of all time, often compared to the Kyoto Protocol to make the latter seem a failure.) Well, it goes without saying that fluorocarbons and ozone depletion are linked intrinsically, even if the most significant one in terms of warming is not depleting the ozone, it is an aspect of the same topic, and what our sentences in the "Public debate" section do is not guide the reader into understanding fluorocarbons... and how some deplete and some warm... but tell them that there is nothing to see there, and that's insufficient. (so I spent my hour or two looking at HFC-23, I will return with something about methane and nitrous later... I don't perceive any rush.. note:Ozone_depletion_and_climate_change#Science_background) ~ R.T.G 18:07, 30 June 2020 (UTC)

Rewrite controversy section

I’ve just done an extensive rewrite of the controversy section. The section was in a surprisingly bad state.

1. I’ve renamed it ‘’denial and misinformation’’. Per Wikipedia:Criticism#"Controversy"_section one should name the controversy explicitly instead of choosing the vague section title ‘controversy’. I don’t think the word controversy is used in the public debate now anymore anyway.
2. (As such, I’ve deleted mention about population control.)
3. The old section provided a bit of a false balance, stating that there were ‘disputes’ about everything instead of manufactured disagreement. I’ve made the tone in line with scientific articles about climate change denial.
4. The old section relied heavily on old sources, opinion pieces, newspaper articles cited as if they were scientific, a snapshot report and an uncontextualized overview of statements from some oil companies. I’ve deleted those; only one source is the same.
5. I’ve left out the changes of oil companies’ denial as I couldn’t find a good scientific source for it, but I’m okay with putting it back if a proper source is found. (secret funding may still be a thing, as it has in the past).

Because the tone of the subsection is much stronger now (in line with scientific research), I really hope we can agree to not put any biased or partisan (even high-quality biased such as NYT) sources in there, to maintain a high level of trust from our readers.

Of course, feedback and improvements are welcome! Femke Nijsse (talk) 05:34, 27 June 2020 (UTC)

Caption copied from Climate change denial: One deceptive approach is cherry picking data from short time periods to assert that global average temperatures are not rising. Red Blue trendlines show short-term countertrends that mask longer-term trends that are shown by blue red trendlines. Such representations have been applied to the so-called Global warming hiatus (red blue dots, 1998-2013).

.

P.S. I know we've come to a difficult consensus of all the pictures used, but please consider using this one instead of the one pictured now. Femke Nijsse (talk) 06:14, 27 June 2020 (UTC)

— Thanks one more time, Femke, for your massive, well-informed, and well-considered efforts.

— I do think this "cherry-picking" animated GIF is an improvement over the "Greenhouse emissions by sector" (GHebs) graphic since the GIF directly represents the subject of the sub-section ("denial and misinformation"). In contrast, GHebs merely suggest an implied motivation by stakeholders rather than proof of deception.

— We could look for or create a graphic representing "denial and misinformation" as a general concept but this GIF was the best I could think of when I created it for the Climate change denial article. I'm not sure if the Grist and Skeptical Science references (in the Commons file description page) are needed, or are the best references, to support any caption. —RCraig09 (talk) 17:41, 27 June 2020 (UTC)

— I just changed the GIF so the red bars are shorter, commensurate with the shorter time periods they cover. —RCraig09 (talk) 19:38, 27 June 2020 (UTC)

References

Thanks Femke, I think your edits were a significant improvement to those paragraphs; they are now more concise and readable. Focusing on information about climate change denial will help the reader understand what’s happening today. Regarding the current graphic image...I don’t find it very helpful. To me it insinuates that the Industry and Land Use sectors have the largest stake in climate change denial (which i’m not sure is true), it doesn’t seem to cite any reliable source in the caption, and so it seems to have an OR feel to it. I personally don’t think that there needs to be a graphic image used to support the text as it’s currently written...to me it stands perfectly well on its own.Dtetta (talk) 19:54, 27 June 2020 (UTC)

Okay please delete it. Femke Nijsse (talk) 07:16, 29 June 2020 (UTC)

We all seem to agree the text is well written. Further, when considering our readers I continue to believe in applying the "Show, don't tell" principle to favor including images where possible. Unless we can find a broader-concept image to illustrate denial/misinformation, I think the above 'cherry picking' GIF should be inserted. Objections? —RCraig09 (talk) 06:12, 2 July 2020 (UTC)

Go ahead (and maybe recover the protest picture I accidentlily removed, if you feel like it). Femke Nijsse (talk) 06:42, 2 July 2020 (UTC)

Substitution complete. I didn't re-post the protest picture(s) since I thought they were a bit WP:NOTNEWS-ish, and not instructive. —RCraig09 (talk) 04:15, 3 July 2020 (UTC)

Agricultural byproducts

One of the biggest controversies around the human effect on climate change after simply denying is the effect of diet choices. There is a tonne of articles on it. A recent survey by Yale University says tht 30% of people claim to hear at least once a month that diet choices are significant towards climate change. Wikipedias global warming article doesn't even mention it. ~ R.T.G 20:21, 28 June 2020 (UTC)

@RTG: It does, at least twice: Individuals can also take actions to reduce their carbon footprint. These include: driving an EV or other energy efficient car and reducing vehicles miles by using mass transit or cycling; adopting a plant-based diet'; reducing energy use in the home; limiting consumption of goods and services; and foregoing air travel. AND particularly from farming ruminants for meat consumption" is "especially troubling". Please read before commenting.

I don't think there is a major controversy about that, not it's a main sticking point for climate denial. There is some misinformation with people either neglecting it or exaggerating it. If you do have high-quality sources that put it as a main point of climate change denial, please add. Femke Nijsse (talk) 07:16, 29 June 2020 (UTC)

Adding something which makes it inconsequential is worse for neutrality than adding nothing. And all estimates put the effects of methane and nitrous between 2nd place and 1st place, at odds with co2 itself... The degrees of effect are well documented and discussed. There are stacks of sources about climate change and farming. It must be people exaggerating it? ~ R.T.G 09:00, 29 June 2020 (UTC)

Misinformation from the 'greens'

Efbrazil added information about misinformation from the left. The reason I called this section denial and misinformation is to leave the door open for that. I didn't come across good sources to add this, and agree with the reverters that the cited sources are not of the quality we need to describe something so controversial (blogs are always border-line). I also agree that we shouldn't mix it up with climate change deniers, that is a different label (i.e., the location of the added text was wrong). I'm going to leave the subsection as is, but open to describing this in one sentence when the scientific literature and or high-quality books have caught up. It is a recent phenomenon that it's a big thing. Femke Nijsse (talk) 07:16, 29 June 2020 (UTC)

Spoiler: had a look, and ended up with a baseline for information rather than clear misinformation.

This seems to be covered in Weart on Impacts and searching for "existential" brings up mention of warnings in 1989, more recently this section down to "Many well-informed military officers and other national security experts, along with many political leaders and a majority of the world’s public, now believed that the impacts of global warming ranked among the most dangerous long-term risks that civilization faced." and footnote 21 which includes "V. Ramanathan quoted by Gary Robbins, "Scripps Says Climate Change May Represent 'Existential' Threat to Humanity," San Diego Union Tribune, Sept. 14, 2017, online here, see Xua and Ramanathan (2017). [also linked as reference]. Ramathan told the newspaper "There is a low probability that the change will be catastrophic. But you would not get on an airplane if you thought there was a 5 percent chance that it was going to crash." He noted that the probability of an existential threat is even smaller, but said, “that chance rises to 20 to 30 percent by 2070.” ........ Such comments displeased EPA Administrator Scott Pruitt, who said that it was inappropriate to focus on the issue while Florida was trying to cope with Irma." [wonder what happened to him?]

Weart gives his own assessment including "hunger, economic upheavals, and millions of refugees fleeing rising seas and deadly heat will undermine civil government and international peace, and we will face a radical impoverishment of the ecosystems that sustain our civilization.(25) This does not amount to the apocalyptic collapse depicted in science-fiction fantasies. If economic growth and technological advances continue their long-term trajectories, at the end of the century we should have the resources to maintain prosperity for at least the more well-off and powerful segments of society. That is, unless we have bad luck...." so that's a reasonable baseline beyond which we're into misinformation.

Weart includes a reference to Butler, Colin D. (2018). "Climate Change, Health and Existential Risks to Civilization: A Comprehensive Review (1989–2013)." International Journal of Environmental Research and Public Health 15: 2266 [doi:10.3390/ijerph15102266]. [which I've not checked]

So I have seen discussion of unreasonable doom scenarios, such as rapid release of clathrates from Arctic warming, but so far haven't found a good source dismissing points as misinformation. . . dave souza, talk 11:26, 29 June 2020 (UTC)

Shorten the section on History of the science?

I am wondering if the section on "History of the science" should be shortened as there is a separate article for it, and this section here should just give some main statements and otherwise let people click through to the sub-article. And apart from shortening, is it actually a good summary of the sub-article? The sub-article seems to go back much further in time which I find confusing. EMsmile (talk) 12:03, 27 June 2020 (UTC)

I believe dave souza first wrote it. I shortened it a bit, but didn't want to go further without knowing how much support there is for it. We have since expanded the GHG and mitigation sections, which makes the problem of having a long article a bit more pronounced. I still support to shorten it, maybe bring it to 50% or 75% of its current size. I don't mind it starting a bit earlier than the other article, but I do feel the first paragraph to be too wordy. Also, the section title is awkward. What about Discovery? Femke Nijsse (talk) 13:06, 27 June 2020 (UTC)

Sure, this section was written from scratch, and it's a bit of unfinished work bringing History of climate change science into line with it. There's probably some stuff here that needs to be covered or expanded in the main history article. The section here's already been shortened, and it focusses on discovery of global warming rather than the broader history covered in the main article, so a retitling of the section sounds a good idea. . . dave souza, talk 13:18, 27 June 2020 (UTC)

I think in particular that the first two paragraphs should be shortened. We want to discuss the discovery of climate change, not of the greenhouse effect. The third paragraph is good as it is, and the last paragraph is almost there (I'd remove the first line). I've removed some details I thought details. An improvement? Femke Nijsse (talk) 08:24, 28 June 2020 (UTC)

Works so far, think the development of the concept of the greenhouse effect is central to the idea of global warming, which is the title of this article. Have tried focussing and tightening it to show how the analogy developed from basic physics, in all slightly shorter than your version but losing some nuances. For the broader topic of discovery of climate change, the first paragraph of User:Dave souza/History of the science covered the early stages, don't know if a sentence summarising that would be worthwhile.
Also, have tightened the last paragraph: Plass was mentioned but not linked, his significance in an earlier sentence had been lost. . dave souza, talk 11:24, 28 June 2020 (UTC)

Thank you both, Femke Nijsse and dave souza for your edits! I am just not sure if "discovery" is a better section title though. I would prefer using "standard" headings in Wikipedia articles as much as possible and "history" is a standard section title. (and I disagree with others who want to put history early in the article, I think it is better off towards the end, near "society and culture" normally). Also "discovery" makes me think of a "one off" event, which this one wasn't. If we are linking to the sub-article on history as the "main" article (rather than calling it "further") then we really just need a summary here of what the "main" article is saying about the history of the scientific understanding of global warming. EMsmile (talk) 02:41, 29 June 2020 (UTC)

Definition

@Femkemilene: this[9] isn't supposed to represent a change in definition, I'm simply trying to streamline edit parts like "It is..." , "measurements and by measurements" , "its effects" , to link glacial study, and just generally shuffle around that sentence about "It is a major aspect of climate change..." I imagine you are saying my use of "surface" temperature has introduced an inaccuracy? ~ R.T.G 12:06, 29 June 2020 (UTC)

You implied that global warming includes precipitation, whereas that is only part of the definition of climate change. Drastic changes in the first paragraph are often first proposed on the talk page, to avoid these good faith errors in this important topic. I agree that the first paragraph is a bit awkward. Femke Nijsse (talk) 12:10, 29 June 2020 (UTC)

P.S. Specifically, I'd be okay with removing and has been demonstrated by direct temperature measurements and by measurements of various effects of the warming. Femke Nijsse (talk) 12:12, 29 June 2020 (UTC)

@Femkemilene: with the first sentence it sort of says, "is the, of the, of the, and the"... phrase joiners... was also trying to cut that while preserving key phrases. I propose a similar edit to what I already tried, except preserving the phrase "climate system" in the first sentence, moving "precipitation" to the variables of evidence ("global warming is proven by measuring..."), and just to drop "surface temperature"...? It will be little more than a shuffle of what was already there. ~ R.T.G 12:27, 29 June 2020 (UTC)

Apart from the error I mentioned before, there were three other problems with your edit:

• Proof is a word that is technically reserved for mathematics. In science, you can never proof something, just get more and more sure you're not wrong.
• Climate change redirects to this article, so you shouldn't link it
• The word however was improperly placed.

Dtetta has been immensely helpful in drafting the current lede. What do you think of my more modest proposal of deleting the second half of the first sentence? The last sentence of the paragraph already talks about observations. If we make the first sentence less unwieldy, we could add a few words to the last sentence. Femke Nijsse (talk) 14:34, 29 June 2020 (UTC)

Apologies for my late response...I seem to be automatically getting logged out, and my notifications then seem to go away. I think the July 1 version of the first paragraph looks fine. I was actually looking at this last week, and was planning on proposing that we edit the first paragraph to look a little more like one of NASA’s:

“Global warming is the long-term heating of Earth’s climate system observed since the pre-industrial period (between 1850 and 1900) due to human activities, primarily fossil fuel burning, which increases heat-trapping greenhouse gas levels in Earth’s atmosphere. The term is frequently used interchangeably with the term climate change, though the latter refers to both human- and naturally produced warming and the effects it has on our planet. It is most commonly measured as the average increase in Earth’s global surface temperature.”

This NASA paragraph accomplishes a lot fairly succinctly (particularly the first sentence), and to me has a welcoming feel to it. I think an engaging first paragraph is important, and the current WP version also does that very well. In addition, it includes some important points that NASA misses. I think it could be improved slightly by adopting wording closer to NASA’s, but It also reads well as is.Dtetta (talk) 20:12, 1 July 2020 (UTC)

Agree, except for one point – ongoing isn't good English, in my opinion, could we change that to continuing? Otherwise, the first paragraph looks good to me. The associated effects are suitably covered in the second sentence. . . dave souza, talk 21:33, 1 July 2020 (UTC)

I realize folks want to put the scope and title issue to bed for awhile, but I've been away for months and am looking... or trying to look.... at this fresh. Either I failed to get fresh eyes or I again came to believe the article is structurally flawed for all the reasons we've argued endlessly before. The lack of resolution shows, maybe, in the ambiguous use of "its" in the second sentence.

• Currently the first two sentences read --

Global warming is the ongoing rise of the average temperature of the Earth's climate system. It is a major aspect of climate change which, in addition to rising global surface temperatures, also includes its effects, such as changes in precipitation.

• A noob may be confused whether "its" means global warming or climate change. Using context and my own knowledge, next I will substitute to show what I think is intended --

Global warming is the ongoing rise of the average temperature of the Earth's climate system. Global warming is a major aspect of climate change which, in addition to rising global surface temperatures, also includes global warming's effects, such as changes in precipitation.

• So now substituting the predicate of Sentence 1 into Sentence 2 it reads --

Global warming is the ongoing rise of the average temperature of the Earth's climate system. Global warming is a major aspect of climate change which, in addition to rising global surface temperatures, also includes (the) effects of the ongoing rise of the average temperature of the Earth's climate system, such as changes in precipitation.

Questions raised by this text include -

(A) Are there other "major aspects of climate change" outside of the warming or warming's effects? On the earth science side I can't think of any. Obviously policy responses and attribution studies are sociopolitical in nature.

(B) Sentence one speaks of climate system warming. Then sentence two suddenly confuses matters by using the narrow technical definition (i.e., increasing global surface temperature)

Alterantive

Personally I think the BEST idea is to make an appropriate title change. But in lieu thereof, this might pass muster and is based on the MOS, which says you don't have to use the title as the first sentence subject if doing that makes it too awkward. So I propose this instead.

The rising average temperature of Earth's climate system, called global warming, is driving changes in temperature, precipitation, arrival of seasons, and more. Collectively, global warming and its effects are known as climate change. While there have been prehistoric periods of global warming, observed changes since the mid-20th century have been unprecedented in rate and scale.

If we invoke WP:FIRSTSENTENCE's permission to not use the article title as the subject for the first sentence, we have more options. Comments on this approach, maybe with other words if you don't like mine? NewsAndEventsGuy (talk) 23:01, 1 July 2020 (UTC)

I like it! Only drawback, the sentence now says that rising temperature drives changes in temperature. With the strict definition (GW only referring to surface warming), that would make sense, but in the current wording it doesn't. So we could say: driving chances in railfall patterns, storms

The rising average temperature of Earth's climate system, called global warming, is driving changes in railfall patterns, storms and arrival of seasons, and more. Collectively, global warming and its effects are known as climate change. While there have been prehistoric periods of global warming, observed changes since the mid-20th century have been unprecedented in rate and scale.

(A): technically, only global warming's climate effects (precipitations, storms and so), are included in climate change. Sometimes other physical effects (sea level rise, acidification) are also included.

(B) yeah, different definitions... I just throw my arms in the air from despair. Would be nice to be consistent in our choice tough, but put other definitions in the notes. Definition section can then deal properly with it. Femke Nijsse (talk) 06:40, 2 July 2020 (UTC)

Thanks for catching the circularity (warming is warming), and your tweaks are fine with me. I don't think we need a citation (WP:LEADCITE) but don't care if we use one. General comment.... It's interesting, Femke.... in the west, as it is sometimes called, we are used to thinking of teensy parts sliced out of the system and analyzed and defined as a stand alone thing. Then with time we gradually understand them as part of the dynamic system from where they came. And so at first narrow specialty scientists thought of GW as just rising surface temps. TOday, a few decades later, specialists such as yourself seem to be comfortable including GW's effects under the "climate change" label, but still slow to include things like sea level rise. On the other hand, generalists.... professional in systems ecology and the like.... have already been doing that. As they should, since with every bit of sea level change, every strand in the web of the climate system twitches a bit. But then my background is closer to systems ecology. NewsAndEventsGuy (talk) 12:57, 2 July 2020 (UTC)

Effects for that list might also include lithotrophs and the biogeochemical cycles, i.e., the bacterial processes by which the earth captures carbon and cools itself. Also the Gulf Stream effect... cooling of the poles is mentioned on the article, but here in Britain and Ireland we have been noticing not only record heat waves, but near record lows on par with the extremes normally only experienced in mainland Europe. This is a well documented and theorised effect of global warming related to the salinity of the Atlantic ocean, which doesn't seem to be mentioned on Wikipedia at all... Also, regarding thawing tundra, there are several things going on with that too. Scandinavia is changing. The balance between various animals is changing owing to climate changes. And one more interesting item which may seem more relevant during this virus crisis is the possibility of suspended plague-like viruses being released as frozen life thaws out[10]. ~ R.T.G 17:13, 2 July 2020 (UTC)

It is mentioned in the see also section of Gulf Stream... Shutdown of thermohaline circulation. ~ R.T.G 17:16, 2 July 2020 (UTC)

@Femkemilene, under "climate adaptation" do we have to start wearing helmets? I got a roaring laugh out of the typo in your red text! Choo choo!
@All, Seriously now... working with Femke's tweak in red, I looked in the main body of the article to verify the effects are talked about in the main body, since the lede is only supposed to summarize the main body. I don't believe we need or should add cites. First off, we don't need them per WP:LEADCITE, Second, unless someone knows a single cite for each parsed bit we'd need more than one, and that means clutter in the lead. Third, All of these impacts are discussed, with citation, under Global_warming#Physical_environment and Global_warming#Nature_and_wildlife. So how about we go with this?

The rising average temperature of Earth's climate system, called global warming, is driving changes pattern in rainfall patterns, extreme weather, arrival of seasons, and more. Collectively, global warming and its effects are known as climate change. While there have been prehistoric periods of global warming, observed changes since the mid-20th century have been unprecedented in rate and scale.

NewsAndEventsGuy (talk) 19:19, 6 July 2020 (UTC)

I'm opposed to wearing helmets. The extra deaths from people not bothering to walk anymore (exercise!) will surely overtake the rails falling on their heads.

Go ahead. Remove the first instance of word pattern. At FAR, they seem to be keen on very few citations in the lede. To not confuse reader, can you move all uncontroversial cites of lede to body (or, simply delete if they would cause overcite)? The terminology section is somewhat weakly cited for difference GW and CC, so would be a waste if we simply delete instead of partially save cites. I think the first paragraph needs the last cite; quite a strong statement that CC has been unprecendented in scale and rate. FN as IP; (wikienforcer). 06:19, 7 July 2020 (UTC)

Thanks for commenting. (A) The very specific suggestion is a citation for the last sentence. I think I added that, with a cite, a long time ago. In any case, the cite used at the start of 2018 was <ref>{{Cite web|url=https://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_SPM_FINAL.pdf|title=IPCC, Climate Change 2013: The Physical Science Basis – Summary for Policymakers (AR5 WG1)|last=|first=|date=|website=|page=4|access-date=|quote=Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia.}}</ref>. Sure, we can use that again, though it needs formatting with the current ref templates, and in any case might be named ref already (I confess I haven't yet looked). (B) The other suggestions are rather vague. Do you have any specifics you'd like to see? NewsAndEventsGuy (talk) 10:27, 7 July 2020 (UTC)

(A) the citation that's there can stay. (currently note 4), no need to invoke old citation, which referred to AR5 instead of SR15 and would fail verification (less strong). (B) Show, not tell. I've removed about 10 cites from the lede that were uncontroversial, and reflected in the lede. I think it's odd if only the first paragraph was devoid of cites. I think notes 2 and 3 need to be moved to the terminology section, whose second paragraph may need a small rewrite to be more in line with these sources. FN as IP; (wikienforcer).

I tried finding a source for our statement that GW is warming of the entire Earth system, but most informal definitions only name the atmosphere (with formal definitions, and some informal, further specifying surface temperature). Let's change the first sentence to 'The rising average temperature of Earth's atmosphere, called global warming — Preceding unsigned comment added by 82.39.162.179 (talk) 14:52, 7 July 2020 (UTC)

See notes 3 4 and 5 of this version. Also, IPCC AR4 WG1 SPM @pg 5, ""Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level." [11] NewsAndEventsGuy (talk) 15:05, 7 July 2020 (UTC)

These sources say: warming is happening, judges by blabla not global warming is blabla . If we define the term global warming in the lede, we have to have a source to back up a definition. FN 15:57, 7 July 2020 (UTC)

Gulf Stream and general thermohaline shutdown

The article says one sentence about the receding Gulf Stream. It says " Another example is the possibility..." The slowdown of the Gulf Stream is beyond theory now[12]. User:Femkemeline wants to prevent even having a see also section[13]. Shutdown of thermohaline circulation is a major aspect of global warming, particularly in the anglosphere. ~ R.T.G 17:47, 2 July 2020 (UTC)

(A) Per the WP:MOS we don't list items in "see also" that were linked in the article body. Go into edit mode on the full article and search for "ocean" and then do another search for "thermohaline." You'll find existing article text --

• As the temperature difference between the Arctic and the equator decreases, ocean currents that are driven by that temperature difference, like the [[Gulf Stream]], weaken.
• Another example is the possibility for the [[Atlantic Meridional Overturning Circulation]] to [[Shutdown of thermohaline circulation|slow or shut down]]...
• Afterwards, the ocean's [[Thermohaline circulation|overturning circulation]] distributes it deep into the ocean's interior, where it accumulates over time as part of the [[carbon cycle]].
• As more CO₂ and heat are absorbed by the ocean, it is acidifying and ocean circulation can change, changing the rate at which the ocean can absorb atmospheric carbon.

(B) The source you cite says "Scientists disagree on whether climate change or natural cycles account for the slowdown. But a consensus has emerged that climate change will lead to a slower Gulf Stream system in the future, as melting ice sheets in Greenland disrupt the system with discharges of cold fresh water."

(C) You've made a vague complaint. Please post some draft text to this thread for us to consider. NewsAndEventsGuy (talk) 18:28, 2 July 2020 (UTC)

That's not what the MOS says. It just says that some comprehensive articles do not have a see also at all. A see also section links further reading on a topic. It is one of the most useful and basic elements of Wikipedia. It is not a sign of a poor article. Beside that the item I linked covers more than the Atlantic and is specifically about the effects of global warming.

Item (B) I do not see how this supports exclusion. It says there is consensus the Gulf Stream will soon be affected, but disagreement if it is already affected... Which, given the nature of global warming... doesn't really make sense, does it? Only the extent to which it is affected so far can truly be disputed.

Proposed text: See also: Shutdown of thermohaline circulation ~ R.T.G 18:58, 2 July 2020 (UTC)

As for the list of quotes from the article, it's insufficient. The effects of global warming on, the Gulf Stream in particular of the thermohaline currents, is widely published as a significant aspect of global warming. The word "salinity" does not even appear on this article. ~ R.T.G 19:05, 2 July 2020 (UTC)

It's kind of funny because this article is very careful to say that record years are inconsequential, that the average temperature of the earth changes little... but it has long been told that it only takes a couple of degrees to destroy the whole thing. It is these extremes which make the worst aspect of global warming, and this is best explained with the shut down of thermohaline currents introducing cold extremes in temperate areas at the same time as magnifying warming in tropical areas by shutting down the cooling mechanism. ~ R.T.G 19:10, 2 July 2020 (UTC)

At the end of the day, I've given maybe 3 or 4 minor points of improvement which would significantly increase the dissemination of the topic on this article. Each of them has been exploded into a large debate. You can be sure, I am in opposition to this being a featured article. The idea of the same people supporting cut-down elements of a topic, and also opposing a see also section entirely, on a wide ranging controversial topic... gives me nothing but suspicion... This article should have a massive see also section, appropriate to the subject. Anything less is wrong, wrong, wrong. ~ R.T.G 19:18, 2 July 2020 (UTC)

Does it make more sense to force a reader to read a whole article to find the see also section? No. Most people will look elsewhere in that circumstance. That is why there are see also sections to begin with. They aren't an extension to the articles prose. They are a compliment to the subjects dissemination. When the MOS talks about a comprehensive article not requiring a see also, that means that there is little information left to find by searching other articles, not that a topic has been superficially mentioned in the articles body, but that it has been comprehensively covered. That is elementary. ~ R.T.G 19:38, 2 July 2020 (UTC)

• opposed per MOS @ WP:NOTSEEALSO which says in part As a general rule, the "See also" section should not repeat links that appear in the article's body. NewsAndEventsGuy (talk) 00:40, 3 July 2020 (UTC)

Note: "Shutdown of thermohaline circulation" does not "appear" in the articles body and it is obviously ridiculously wrong to force a reader to read a whole article and hover over piped links to find complimentary articles on major aspects of a topic. I mean, you are either improving an encyclopaedia or you aren't. Now, I'm not interested in being childish, but there is extensive talkpage content here now, the idea of having no see also section, is the dumbest thing I have ever read up in here that isn't purposely designed to be dumb. You must have gone to some effort to keep a see also section off this article in particular, and the worst thing about it is, the recommended reading (see also) section, is ridiculous. It is like you are trying to guide people off the site. Hum. Ding. ~ R.T.G 03:34, 3 July 2020 (UTC)

I'm just going to note clearly, "in general", i.e. most topics which are notable enough to have an article, should not repeat every link that appears in the article text. In the circumstance, however, where an article represents a gateway to a wide range of branching aspects to a topic, such as global warming, which is not the "general" situation with most articles... simply adding a cram-load of piped links into the text of the article does not treat the subject as a gateway topic. To be the best source of information as we possibly can, we guide the reader into the most important supporting topics, without forcing them to read this gateway article, again and again, hovering over links for needles piped under haystacks, it is not sensible with regard to the output. You must have a see also section, on the global warming article, or a structure which actually substitutes it in a functional way, and no kind of lawyering is going to truly dispute that. ~ R.T.G 21:46, 6 July 2020 (UTC)

Piped links, in the middle of prose, in a 300kb article, are not a substitution for clearly listed links to relevant supporting topics. Not even nearly. And pretending that you cannot even see any sense in that sort of suggestion, is probably more of a social issue than an encyclopaediac one. ~ R.T.G 21:50, 6 July 2020 (UTC)

Well, if you can persuade folks at the Village Pump to modify the MOS to create some sort of different guideline for what you call "gateway" articles, we can revisit.NewsAndEventsGuy (talk) 02:57, 7 July 2020 (UTC)

I did not dispute the MOS, friend. You are interpreting the MOS, with relation to these postings. I am interpreting the global warming article, in relation to the MOS. See also sections, are not patches for broken articles, which, if I am not mistaken... ~ R.T.G 07:41, 7 July 2020 (UTC)

I can live with fact we disagree. Now what? NewsAndEventsGuy (talk) 10:28, 7 July 2020 (UTC)