Talk:Climate change

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Frequently asked questions

To view an answer, click the [show] link to the right of the question. To view references used by an answer, you must also click the [show] for references at the bottom of the FAQ.

Q1: Is there really a scientific consensus on climate change?

A1: Yes. The IPCC findings of recent warming as a result of human influence are explicitly recognized as the "consensus" scientific view by the science academies of all the major industrialized countries. No scientific body of national or international standing presently rejects the basic findings of human influence on recent climate. This scientific consensus is supported by over 99% of publishing climate scientists.^[1]

Q2: How can we say climate change is real when it's been so cold in such-and-such a place?

A2: This is why it is termed "global warming", not "(such-and-such a place) warming". Even then, what rises is the average temperature over time – that is, the temperature will fluctuate up and down within the overall rising trend. To give an idea of the relevant time scales, the standard averaging period specified by the World Meteorological Organisation (WMO) is 30 years. Accordingly, the WMO defines climate change as "a statistically significant variation in either the mean state of the climate or in its variability, persisting for an extended period (typically decades or longer)."^[2]

Q3: Can't the increase of CO₂ be from natural sources, like volcanoes or the oceans?

A3: While these claims are popular among global warming skeptics,^[3]^[4] including academically trained ones,^[5]^[6] they are incorrect. This is known from any of several perspectives:

Current human emissions of CO₂ are at least 100 times larger than volcanic emissions. Measurements of CO₂ levels over the past 50 years do not show any significant rises after eruptions.^[7] This is easily seen in a graph of CO₂ concentrations over the past 50 years: the strongest eruption during the period, that of Mount Pinatubo in 1991, produced no increase in the trend.
Isotopic analysis of atmospheric carbon dioxide shows the observed change in the ratio of carbon isotopes reflects the isotopic ratios in fossil fuels.^[8]
Atmospheric oxygen content is decreasing at a rate that agrees with the amount of oxygen being used to burn fossil fuels.^[9]
If the oceans were giving up some of their carbon dioxide, their carbon dioxide concentration would have to decrease. But instead we are measuring an increase in the oceans' carbon dioxide concentration, resulting in the oceans becoming more acidic (or in other words, less basic).^[10]

Q4: I think the article is missing some things, or has some things wrong. Can I change it?

A4: Yes. Keep in mind that your points need to be based on documented evidence from the peer-reviewed literature, or other information that meets standards of verifiability, reliability, and no original research. If you do not have such evidence, more experienced editors may be able to help you find it (or confirm that such evidence does not exist). You are welcome to make such queries on the article's talk page but please keep in mind that the talk page is for discussing improvements to the article, not discussing the topic. There are many forums that welcome general discussions of global warming, but the article talk page is not such a forum.

Q5: Why haven't the graphs been updated?

A5: Two reasons:

There are many images used in the articles related to global warming, and there are many reasons why they may not be updated with the latest data. Some of the figures, like the Global Warming Map, are static, meaning that they are intended to show a particular phenomenon and are not meant to be updated frequently or at all. Others, like the Instrumental Temperature Record and Northern Hemisphere Sea Ice Extent Anomalies, use yearly data and thus are updated once per year—usually in mid- to late-January, depending upon when the data is publicly released, and when a volunteer creates the image. Still others, like Mauna Loa Carbon Dioxide, use monthly data. These are updated semi-regularly.
However, just because an image is 6 months or a year old does not mean it is useless. Robert A. Heinlein is credited with saying, "Climate is what you expect, weather is what you get", meaning that climate is defined as a long-term average of weather, usually about 30 years. This length was chosen to eliminate the year-to-year variations.^[11] Thus, in terms of climate change, any given year's data is of little import.

Q6: Isn't climate change "just a theory"?

A6: People who say this are abusing the word "theory" by conflating its common meaning with its scientific meaning. In common usage, "theory" can mean a hunch or guess, but a scientific theory, roughly speaking, means a coherent set of explanations that is compatible with observations and that allows predictions to be made. That the temperature is rising is an observation. An explanation for this (also known as a hypothesis) is that the warming is primarily driven by greenhouse gases (such as CO₂ and methane) released into the atmosphere by human activity. Scientific models have been built that predict the rise in temperature and these predictions have matched observations. When scientists gain confidence in a hypothesis because it matches observation and has survived intense scrutiny, the hypothesis may be called a "theory". Strictly speaking, scientific theories are never proven, but the degree of confidence in a theory can be discussed. The scientific models now suggest that it is "extremely likely" (>95%) to "virtually certain" (>99%) that the increases in temperature have been caused by human activity as discussed in the IPCC Fifth Assessment Report. Global warming via greenhouse gases by human activity is a theory (in the scientific sense), but it is most definitely not just a hunch or guess.

Q7: Does methane cause more warming than CO₂?

A7: It's true that methane is more potent molecule for molecule. But there's far less of it in the atmosphere, so the total effect is smaller. The atmospheric lifetime of methane (about 10 years) is a lot shorter than that of CO₂ (hundreds to thousands of years), so when methane emissions are reduced the concentration in the atmosphere soon falls, whereas CO₂ accumulates in the atmosphere over long periods. For details see the greenhouse gas and global warming potential articles.

Q8: How can you say there's a consensus when lists of "skeptical scientists" have been compiled?

A8: Consensus is not the same as unanimity, the latter of which is impractical for large groups. Over 99% of publishing climate scientists agree on anthropogenic climate change.^[1] This is an extremely high percentage well past any reasonable threshold for consensus. Any list of "skeptical scientists" would be dwarfed by a comparably compiled list of scientists accepting anthropogenic climate change.

Q9: Did climate change end in 1998?

A9: One of the strongest El Niño events in the instrumental record occurred during late 1997 through 1998, causing a spike in global temperature for 1998. Through the mid-late 2000s this abnormally warm year could be chosen as the starting point for comparisons with later years in order to produce a cooling trend; choosing any other year in the 20th century produced a warming trend. This no longer holds since the mean global temperatures in 2005, 2010, 2014, 2015 and 2016 have all been warmer than 1998.^[12] More importantly, scientists do not define a "trend" by looking at the difference between two given years. Instead they use methods such as linear regression that take into account all the values in a series of data. The World Meteorological Organisation specifies 30 years as the standard averaging period for climate statistics so that year-to-year fluctuations are averaged out;^[2] thus, 10 years isn't long enough to detect a climate trend.

Q10: Wasn't Greenland much warmer during the period of Norse settlement?

A10: Some people assume this because of the island's name. In fact the Saga of Erik the Red tells us Erik named the new colony Greenland because "men will desire much the more to go there if the land has a good name."^[13] Advertising hype was alive and well in 985 AD.

While much of Greenland was and remains under a large ice sheet, the areas of Greenland that were settled by the Norse were coastal areas with fjords that, to this day, remain quite green. You can see the following images for reference:

A map of the Eastern Settlement
A satellite image of that area today
A map of the Western Settlement
A satellite image of that area today
A zoom in on the general area where the Brattahlíð (Erik the Red's farm) and Garðar farms were located

Q11: Are the IPCC reports prepared by biased UN scientists?

A11: The IPCC reports are not produced by "UN scientists". The IPCC does not employ the scientists who generate the reports, and it has no control over them. The scientists are internationally recognized experts, most with a long history of successful research in the field. They are employed by various organizations including scientific research institutes, agencies like NASA and NOAA, and universities. They receive no extra pay for their participation in the IPCC process, which is considered a normal part of their academic duties.

Q12: Hasn't global sea ice increased over the last 30 years?

A12: Measurements show that it has not.^[14] Claims that global sea ice amounts have stayed the same or increased are a result of cherry picking two data points to compare, while ignoring the real (strongly statistically significant) downward trend in measurements of global sea ice amounts.

Arctic sea ice cover is declining strongly; Antarctic sea ice cover has had some much smaller increases, though it may or may not be thinning, and the Southern Ocean is warming. The net global ice-cover trend is clearly downwards.

Q13: Weren't scientists telling us in the 1970s that the Earth was cooling instead of warming?

A13: They weren't – see the article on global cooling. An article in the Bulletin of the American Meteorological Society has reviewed the scientific literature at that time and found that even during the 1970s the prevailing scientific concern was over warming.^[15] The common misperception that cooling was the main concern during the 1970s arose from a few studies that were sensationalized in the popular press, such as a short nine-paragraph article that appeared in Newsweek in 1975.^[16] (Newsweek eventually apologized for having misrepresented the state of the science in the 1970s.)^[17] The author of that article has repudiated the idea that it should be used to deny global warming.^[18]

Q14: Doesn't water vapour cause 98% of the greenhouse effect?

A14: Water vapour is indeed a major greenhouse gas, contributing about 36% to 70% (not 98%) of the total greenhouse effect. But water vapour has a very short atmospheric lifetime (about 10 days), compared with decades to centuries for greenhouse gases like CO₂ or nitrous oxide. As a result it is very nearly in a dynamic equilibrium in the atmosphere, which globally maintains a nearly constant relative humidity. In simpler terms, any excess water vapour is removed by rainfall, and any deficit of water vapour is replenished by evaporation from the Earth's surface, which literally has oceans of water. Thus water vapour cannot act as a driver of climate change.

Rising temperatures caused by the long-lived greenhouse gases will however allow the atmosphere to hold more vapour. This will lead to an increase in the absolute amount of water vapour in the atmosphere. Since water vapour is itself a greenhouse gas, this is an example of a positive feedback. Thus, whereas water vapour is not a driver of climate change, it amplifies existing trends.

Q15: Is the fact that other solar system bodies are warming evidence for a common cause (i.e. the sun)?

A15: While some solar system bodies show evidence of local or global climate change, there is no evidence for a common cause of warming.

A 2007 National Geographic article described the views of Khabibullo Abdusamatov, who claims that the sun is responsible for global warming on both Earth and Mars.^[19] Abdussamatov's views have no support in the scientific community, as the second page of the National Geographic article makes clear: "'His views are completely at odds with the mainstream scientific opinion,' said Colin Wilson, a planetary physicist at England's Oxford University. [...] Amato Evan, a climate scientist at the University of Wisconsin, Madison, added that 'the idea just isn't supported by the theory or by the observations.'"^[20]
There is no reliable source claiming that Jupiter is warming. However, observations of the Red Spot Jr. storm suggest Jupiter could be in a period of global climate change.^[21]^[22] This is hypothesized to be part of an approximately 70 year global climate cycle, characterized by the relatively rapid forming and subsequent slow erosion and merging of cyclonic and anticyclonic vortices that help transfer heat between Jupiter's poles and equator. The cycle works like this: As the vortices erode, heat exchange is reduced; this makes the poles cool down and the equatorial region heat up; the resulting temperature difference destabilizes the atmosphere, leading to the creation of new vortices.^[23]^[24]
Pluto has an extremely elliptical orbit with a period of about 248 years. Data are sparse, but two data points from 1988 and 2002 indirectly suggest that Pluto warmed between those two dates.^[25] Pluto's temperature is heavily influenced by its elliptical orbit – it was closest to the sun in 1989 and has slowly receded since. Because of thermal inertia, it is expected to warm for a while after it passes perihelion (similar to how a sunny day's warmest temperatures happen during the afternoon instead of right at noon). No other mechanism has so far been seriously suggested. Here is a reasonable summary, and this paper discusses how the thermal inertia is provided by sublimation and evaporation of parts of Pluto's atmosphere. A more popular account is here and in Wikipedia's own article.

Q16: Do scientists support climate change just to get more money?

A16: No,

Scientists participate in international organizations like the IPCC as part of their normal academic duties. They do not receive any extra compensation beyond possibly for direct expenses.
Scientific grants do not usually award any money to a scientist personally, only towards the cost of his or her scientific work.
There is not a shortage of useful things that scientists could study if they were not studying global warming.
- Understanding our climate system better brings benefits independent of global warming. For instance, more accurate weather predictions save a lot of money (on the order of billions of dollars a year), and everyone from insurance agents to farmers wants climate data.^[26]^[27] Scientists could get paid to study climate even if global warming did not exist.

Q17: Doesn't the climate vary even without human activity?

A17: It does, but the fact that natural variation occurs does not mean that human-induced change cannot also occur. Climate scientists have extensively studied natural causes of climate change (such as orbital changes, volcanism, and solar variation) and have ruled them out as an explanation for the current temperature increase. Human activity is the cause at the 95 to 99 percent confidence level (see the IPCC Fifth Assessment Report for details). The high level of certainty in this is important to keep in mind to spot mention of natural variation functioning as a distraction.

Q18: Should we include the view that climate change will lead to planetary doom or catastrophe?

A18: This page is about the science of climate change. It doesn't talk about planetary doom or catastrophe. For a technical explanation, see catastrophic climate change, and for paleoclimatic examples see PETM and great dying.

Q19: Is an increase in global temperature of, say, 3 degrees Celsius (5.4 degrees Fahrenheit) important?

A19: Though it may not sound like much, a global temperature rise of 3 degrees Celsius (5.4 degrees Fahrenheit) is huge in climate terms. For example, the sea level rise it would produce would flood coastal cities around the world, which include most large cities.

Earth's climate has varied significantly over geological ages. The question of an "optimal temperature" makes no sense without a clear optimality criterion. Over geological time spans, ecosystems adapt to climate variations. But global climate variations during the development of human civilization (i.e. the past 12,000 years) have been remarkably small. Human civilization is highly adapted to the current stable climate. Agricultural production depends on the proper combination of soil, climate, methods, and seeds. Most large cities are located on the coast, and any significant change in sea level would strongly affect them. Migration of humans and ecosystems is limited by political borders and existing land use. In short, the main problem is not the higher absolute temperature but the massive and unprecedentedly fast change in climate and the related effects on human societies. The IPCC AR6 WG2 report has a detailed discussion of the effects of rapid climate change.

Q20: Why are certain proposals to change the article discarded, deleted, or ignored? Who is/was Scibaby?

A20: Scibaby is/was a long term abusive sock-master (or coordinated group of sock masters) who has created 1,027 confirmed sock puppets, another 167 suspected socks, and probably many untagged or unrecognized ones. This page lists some recent creations. His modus operandi has changed over time, but includes proposing reasonably worded additions on the talk page that only on close examination turn out to be irrelevant, misinterpreted, or give undue weight to certain aspects. Scibaby is banned, and Scibaby socks are blocked as soon as they are identified. Some editors silently revert his additions, per WP:DENY, while others still assume good faith even for likely socks and engage them.

Q21: What about this really interesting recent peer-reviewed paper I read or read about, that says...?

A21: There are hundreds of peer-reviewed papers published every month in respected scientific journals such as Geophysical Research Letters, the Journal of Climate, and others. We can't include all of them, but the article does include references to individual papers where there is consensus that they best represent the state of the relevant science. This is in accordance with the "due weight" principle (WP:WEIGHT) of the Neutral point of view policy and the "Wikipedia is not an indiscriminate collection of information" principle (WP:IINFO) of the What Wikipedia is not policy.

Q22: Why does the article define "climate change" as a recent phenomenon? Hasn't the planet warmed and cooled before?

A22: Yes, the planet has warmed and cooled before. However, the term "climate change" without further qualification is widely understood to refer to the recent episode and often explicitly connected with the greenhouse effect. Per WP:COMMONNAME, we use the term in this most common meaning. The article Climate variability and change deals with the more general concept.

Q23: Did the CERN CLOUD experiment prove that climate change is caused not by human activity but by cosmic rays?

A23: No. For cosmic rays to be causing global warming, all of the following would have to be true, whereas only the italicized one was tested in the 2011 experiment:^[28]

Solar magnetic field must be getting stronger
The number of cosmic rays reaching Earth must be dropping
Cosmic rays must successfully seed clouds, which requires:

Cosmic rays must trigger aerosol (liquid droplet) formation,
These newly-formed aerosols must grow sufficiently through condensation to form cloud-condensation nuclei (CCN),
The CCN must lead to increased cloud formation, and
Cloud cover on Earth must be declining.

Perhaps the study's lead author, Jasper Kirkby, put it best: "...it [the experiment] actually says nothing about a possible cosmic-ray effect on clouds and climate, but it's a very important first step."^[29]

Q24: I read that something can't fix climate change. Is this true?

A24: Yes, this is true for all plausible single things including: "electric cars", "planting trees", "low-carbon technology", "renewable energy", "Australia", "capitalism", "the doom & gloom approach", "a Ph.D. in thermodynamics". Note that it is problematic to use the word "fix" regarding climate change, as returning the climate to its pre-industrial state currently appears to be feasible only over a timeframe of thousands of years. Current efforts are instead aimed at mitigating (meaning limiting) climate change. Mitigation is strived for through the combination of many different things. See Climate change mitigation for details.

References

^ ^a ^b Powell, James (20 November 2019). "Scientists Reach 100% Consensus on Anthropogenic Global Warming". Bulletin of Science, Technology & Society. 37 (4): 183–184. doi:10.1177/0270467619886266. S2CID 213454806. Retrieved 15 November 2020.
^ ^a ^b "Commission for Climatology Frequently Asked Questions". World Meteorological Organization. Archived from the original on 5 May 2020. Retrieved 14 July 2020.
^ Harris, Tom. "Scientists who work in the fields liberal arts graduate Al Gore wanders through contradict his theories about man-induced climate change". National Post. Archived from the original on 30 August 2011. Retrieved 11 January 2009 – via Solid Waste & Recycling. {{cite web}}: |archive-date= / |archive-url= timestamp mismatch; 4 February 2012 suggested (help)
^ Arriola, Benj. "5 Good Arguments Why GlobalWarming is NOT due to Man-made Carbon Dioxide". Global Warming Awareness Blog. Retrieved 11 January 2009.
^ Ahlbeck, Jarl. "Increase of the Atmospheric Carbon Dioxide Concentration due to Ocean Warming". Retrieved 11 January 2009.
^ Kirby, Simon (11 April 2007). "Top scientist debunks global warming". Herald Sun. Retrieved 11 January 2009.
^ Brahic, Catherine (16 May 2007). "Climate myths: Human CO2 emissions are too tiny to matter". New Scientist. Retrieved 11 January 2009.
^ "More Notes on Global Warming". Physics Today. May 2005. Retrieved 10 September 2007.
^ Battle, M.; et al. (2000). "Global Carbon Sinks and Their Variability Inferred from Atmospheric O2 and d13C". Science. 287 (5462): 2467–2470. doi:10.1126/science.287.5462.2467.
^ The Royal Society (2005). "Ocean acidification due to increasing atmospheric carbon dioxide". Retrieved 9 May 2012.
^ "Met Office: Climate averages". Met Office. Archived from the original on 24 February 2009. Retrieved 23 January 2009.
^ Climate Central (18 January 2017). "2016 Was the Hottest Year on Record". Climate Central. Retrieved 1 February 2017.
^ The Saga of Erik the Red, 1880, English translation by J. Sephton, from the original Eiríks saga rauða.
^ "Cold Hard Facts". Tamino. 8 January 2009. Retrieved 21 January 2009.^{[dead link]}
^ Peterson, T. C.; et al. (2008). "The Myth of the 1970s Global Cooling Scientific Consensus". Bulletin of the American Meteorological Society. 89 (9): 1325. Bibcode:2008BAMS...89.1325P. doi:10.1175/2008BAMS2370.1.
^ Gwynne, Peter (28 April 1975). "The Cooling World". Newsweek. p. 64.
^ Verger, Rob (23 May 2014). "Newsweek Rewind: Debunking Global Cooling". Newsweek.
^ Gwynne, Peter (21 May 2014). "My 1975 'Cooling World' Story Doesn't Make Today's Climate Scientists Wrong". insidescience.org.
^ Ravilious, Kate (28 February 2007). "Mars Melt Hints at Solar, Not Human, Cause for Warming, Scientist Says". National Geographic News. Archived from the original on 2 March 2007. Retrieved 6 March 2008.
^ Ravilious, Kate (28 February 2007). "Mars Melt Hints at Solar, Not Human, Cause for Warming, Scientist Says (page 2)". National Geographic News. Archived from the original on 2 March 2007. Retrieved 6 March 2008.
^ Marcus, Philip; Shetty, Sushil; Asay-Davis, Xylar (November 2006). Velocities and Temperatures of Jupiter's Great Red Spot and the New Red Oval and Implications for Global Climate Change. American Physical Society. Retrieved 9 May 2007.
^ Goudarzi, Sara (4 May 2006). "New Storm on Jupiter Hints at Climate Change". Space.com. Retrieved 9 May 2007.
^ Philip, Marcus S. (22 April 2004). "Prediction of a global climate change on Jupiter" (PDF). Nature. 428 (6985): 828–831. Retrieved 9 May 2007.
^ Yang, Sarah (21 April 2004). "Researcher predicts global climate change on Jupiter as giant planet's spots disappear". University of California, Berkeley. Retrieved 9 May 2007.
^ Elliot, J. L.; et al. (10 July 2003). "The recent expansion of Pluto's atmosphere". Nature (424): 165–168. doi:10.1038/nature01762.{{cite journal}}: CS1 maint: multiple names: authors list (link)
^ Foerster, Jim. "What's The Difference Between Private Weather Companies And The National Weather Service?". Forbes.
^ Eilts, Mike (27 November 2018). "The Role of Weather—and Weather Forecasting—in Agriculture". DTN.
^ "What do the CERN experiments tell us about global warming?". Skeptical Science. 2 September 2011.
^ Brumfiel, Geoff (23 August 2011). "Cloud Formation May Be Linked to Cosmic Rays". Scientific American.

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Attributed and expected effects

This section relates to a previous discussion at Talk:Global warming/Archive 60#Rewrite of attributed and expected effects, and other changes

As I've said previously, I'm not happy with the quality of many areas of this article. Here are the changes I propose to the section on Attributed and expected effects:

Addition of new information on regions and populations most affected
Addition of neutrality and geographical balance tags
Redirect from economics of global warming to economics of global warming#Impacts — Preceding unsigned comment added by Enescot (talk • contribs)

Addition of new information on regions and populations most affected

My proposed addition is in bold:

It is usually impossible to connect specific weather events to global warming. Instead, global warming is expected to cause changes in the overall distribution and intensity of events, such as changes to the frequency and intensity of heavy precipitation. Broader effects are expected to include glacial retreat, Arctic shrinkage including long-term shrinkage of Greenland ice sheet[63], and worldwide sea level rise. Some effects on both the natural environment and human life are, at least in part, already being attributed to global warming. A 2001 report by the IPCC suggests that glacier retreat, ice shelf disruption such as that of the Larsen Ice Shelf, sea level rise, changes in rainfall patterns, and increased intensity and frequency of extreme weather events are attributable in part to global warming.[64] Other expected effects include water scarcity in some regions and increased precipitation in others, changes in mountain snowpack, and some adverse health effects from warmer temperatures.[65]

Regions that are likely to be most affected by global warming are the Arctic, Africa, small islands, and Asian megadeltas. Across all regions, some population groups are particularly at risk from the effects of global warming, e.g., the poor, young children, and the elderly.

Social and economic effects of global warming may be exacerbated by growing population densities in affected areas. Temperate regions are projected to experience fewer cold-related deaths but many more deaths from heat exposure.[66] A summary of probable effects and recent understanding can be found in the report made for the IPCC Third Assessment Report by Working Group II.[64] The newer IPCC Fourth Assessment Report summary reports that there is observational evidence for an increase in intense tropical cyclone activity in the North Atlantic Ocean since about 1970, in correlation with the increase in sea surface temperature (see Atlantic Multidecadal Oscillation), but that the detection of long-term trends is complicated by the quality of records prior to routine satellite observations. The summary also states that there is no clear trend in the annual worldwide number of tropical cyclones.[3]

Additional anticipated effects include sea level rise of 0.18 to 0.59 meters (0.59 to 1.9 ft) in 2090–2100 relative to 1980–1999,[3] new trade routes resulting from arctic shrinkage,[67] possible thermohaline circulation slowing, increasingly intense, in some locations, (but less frequent) hurricanes [68]and extreme weather events,[69] reductions in the ozone layer, changes in agriculture yields, changes in the range of climate-dependent disease vectors,[70] which have been linked to increases in the prevalence of malaria and dengue fever,[71] and ocean oxygen depletion.[72] Increased atmospheric CO2 increases the amount of CO2 dissolved in the oceans.[73] CO2 dissolved in the ocean reacts with water to form carbonic acid, resulting in ocean acidification. Ocean surface pH is estimated to have decreased from 8.25 near the beginning of the industrial era to 8.14 by 2004,[74] and is projected to decrease by a further 0.14 to 0.5 units by 2100 as the ocean absorbs more CO2.[3][75] Heat and carbon dioxide trapped in the oceans may still take hundreds of years to be re-emitted, even after greenhouse gas emissions are eventually reduced.[8] Since organisms and ecosystems are adapted to a narrow range of pH, this raises extinction concerns and disruptions in food webs.[76] One study predicts 18% to 35% of a sample of 1,103 animal and plant species would be extinct by 2050, based on future climate projections.[77] However, few mechanistic studies have documented extinctions due to recent climate change,[78] and one study suggests that projected rates of extinction are uncertain.[79]

Ref:

IPCC (2007). "Climate Change 2007: Synthesis Report. Contribution of Working Groups I, II and III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, Pachauri, R.K and Reisinger, A. (eds.)"]. IPCC, Geneva, Switzerland. pp. 104. [1]. Retrieved 2009-05-20. — Preceding unsigned comment added by Enescot (talk • contribs)

Is there a page reference for the two proposed sentences? I see p a reference to "pp. 104", but that appears to me to be the total length of AR4 including the appendix. ... Kenosis (talk) 20:59, 16 March 2010 (UTC)[reply]

Page 9. Enescot (talk) 21:57, 17 March 2010 (UTC)[reply]

OK, thanks. This material is already dealt with, on the level of specificity you suggest, at Effects_of_global_warming#Regions. I've no objection to it here too, but are practical limits to how much material we can fit into in this article. See WP:Summary style. ... Kenosis (talk) 19:01, 18 March 2010 (UTC)[reply]

Addition of neutrality and geographical balance tags

I do not think that this section is either neutral or sufficient in its geographical coverage of the topic. The description of some topics is biased:

Health impacts
New ocean trade routes

— Preceding unsigned comment added by Enescot (talk • contribs)

Health impacts

This is how health impacts are described at the moment:

Other expected effects include water scarcity in some regions and increased precipitation in others, changes in mountain snowpack, and some adverse health effects from warmer temperatures.

[...] Temperate regions are projected to experience fewer cold-related deaths but many more deaths from heat exposure.

Additional expected effects include [...] changes in the range of climate-dependent disease vectors,[70] which have been linked to increases in the prevalence of malaria and dengue fever,[71]

Compare this with the findings presented in the IPCC Synthesis Report:

The health status of millions of people is projected to be affected through, for example, increases in malnutrition; increased deaths, diseases and injury due to extreme weather events; increased burden of diarrhoeal diseases; increased frequency of cardio-respiratory diseases due to higher concentrations of ground-level ozone in urban areas related to climate change; and the altered spatial distribution of some infectious diseases. {WGI 7.4, Box 7.4; WGII 8.ES, 8.2, 8.4, SPM}
Climate change is projected to bring some benefits in temperate areas, such as fewer deaths from cold exposure, and some mixed effects such as changes in range and transmission potential of malaria in Africa. Overall it is expected that benefits will be outweighed by the negative health effects of rising temperatures, especially in developing countries. {WGII 8.4, 8.7, 8.ES, SPM}
Critically important will be factors that directly shape the health of populations such as education, health care, public health initiatives, and infrastructure and economic development. {WGII 8.3, SPM}

There is an obvious difference between the two: the IPCC report is far less ambiguous that the article currently is. In particular, it says:

Climate change is projected to bring some benefits in temperate areas, such as fewer deaths from cold exposure, and some mixed effects such as changes in range and transmission potential of malaria in Africa. Overall it is expected that benefits will be outweighed by the negative health effects of rising temperatures, especially in developing countries. [emphasis added]

This statement of negative aggregate effects, plus the projection that those impacts will be worse in developing countries, is a key finding of the IPCC report. Yet, it is not mentioned in this article.

You see that there is an imbalance in the regional effects described for health impacts:

Other expected effects include water scarcity in some regions and increased precipitation in others, changes in mountain snowpack, and some adverse health effects from warmer temperatures.

[...] Temperate regions are projected to experience fewer cold-related deaths but many more deaths from heat exposure.

The impacts in temperature regions are described, but the impacts in non-temperate regions are not described.

The coverage of health impacts is biased:

[...] Temperate regions are projected to experience fewer cold-related deaths but many more deaths from heat exposure.

[...] Additional expected effects include [...] changes in the range of climate-dependent disease vectors,[70] which have been linked to increases in the prevalence of malaria and dengue fever,[71]

These impacts are mentioned:

cold-related deaths
heat exposure
climate-dependent disease vectors
malaria
dengue fever

The IPCC report mentions:

increases in malnutrition;
increased deaths, diseases and injury due to extreme weather events;
increased burden of diarrhoeal diseases;
increased frequency of cardio-respiratory diseases due to higher concentrations of *ground-level ozone in urban areas related to climate change;
altered spatial distribution of some infectious diseases
fewer deaths from cold exposure
some mixed effects such as changes in range and transmission potential of malaria in Africa.

I do not see that there's any reason for cold-related deaths, heat exposure, climate-dependent disease vectors, malaria, and dengue fever to have priority/more significance than:

increases in malnutrition;
increased deaths, diseases and injury due to extreme weather events; increased burden of diarrhoeal diseases;
increased frequency of cardio-respiratory diseases due to higher concentrations of ground-level ozone in urban areas related to climate change

An estimate of the size and nature (positive or negative) is depicted in the IPCC Working Group II report, fig 8.3:

Ref:

Confalonieri, U., et al. (2007). "Human health. In: Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [M.L. Parry et al., Eds."]. Cambridge University Press, Cambridge, U.K., and New York, N.Y., U.S.A.. [2]. Retrieved 2009-05-20.

The negative impacts are larger than the positive impacts. The two largest impacts are (largest first): 1. Malnutrition, all negative (high confidence) 2. Malaria, mixed effects (v. high confidence). Increased deaths, diseases and injury due to extreme weather events, all negative (v. high conf)

The relative sizes of the impacts included in the article are:

cold-related deaths (high conf) = ~1/5 the size of malnutrition impacts
heat exposure= not mentioned
climate-dependent disease vectors: not mentioned. "Change in the range of infectious disease vectors" is ~1/4 the size of malnutrition impacts
malaria (v. high conf) = bit smaller than malnutrition
dengue fever = not mentioned, perhaps included as part of the "infectious disease vector" indicator

Based on this figure, I believe that the article is currently biased towards impacts having:

mixed effects rather than negative effects
positive effects rather than negative effects
smaller health impacts rather than large impacts

Suggested changes:

Based on their size, these impacts should be mentioned: 1. Increase in malnutrition 2. Increased deaths, diseases and injury due to extreme weather events 3. Increased frequency of cardio-respiratory diseases from changes in air quality. Increase in the burden of diarrhoeal diseases

For adequate balance across all regions, I suggest that these sentences are added:

With high confidence, IPCC (2007) projected that climate change would bring some benefits in temperate areas, such as fewer deaths from cold exposure, and some mixed effects such as changes in range and transmission potential of malaria in Africa. Health benefits were projected to be outweighed by the negative health effects of rising temperatures, especially in developing countries.

This addition would make existing parts on health impacts redundant.

Sentence shortened:

Existing revision:

Other expected effects include water scarcity in some regions and increased precipitation in others, changes in mountain snowpack, and some adverse health effects from warmer temperatures.

Change to:

Other expected effects include water scarcity in some regions and increased precipitation in others, and changes in mountain snowpack.

Sentence deleted:

[...] Temperate regions are projected to experience fewer cold-related deaths but many more deaths from heat exposure.

Sentence shortened:

Existing sentence:

Additional anticipated effects include sea level rise of 0.18 to 0.59 meters (0.59 to 1.9 ft) in 2090–2100 relative to 1980–1999,[3] new trade routes resulting from arctic shrinkage,[67] possible thermohaline circulation slowing, increasingly intense, in some locations, (but less frequent) hurricanes [68]and extreme weather events,[69] reductions in the ozone layer, changes in agriculture yields, changes in the range of climate-dependent disease vectors,[70] which have been linked to increases in the prevalence of malaria and dengue fever,[71] and ocean oxygen depletion

New sentence:

Additional anticipated effects include sea level rise of 0.18 to 0.59 meters (0.59 to 1.9 ft) in 2090–2100 relative to 1980–1999,[3] new trade routes resulting from arctic shrinkage,[67] possible thermohaline circulation slowing, increasingly intense, in some locations, (but less frequent) hurricanes [68]and extreme weather events,[69] reductions in the ozone layer, changes in agriculture yields, and ocean oxygen depletion — Preceding unsigned comment added by Enescot (talk • contribs)

New ocean trade routes

The existing revision states:

Additional anticipated effects include [...] new trade routes resulting from arctic shrinkage [...]

This is an impact that affects polar regions, coastal areas, and human industry, settlement, and society. Therefore, by its inclusion, we should have a balanced description of impacts affecting coastal areas, polar regions, and industry, settlements and society. Let's take coastal areas first. From the IPCC Synthesis report:

Coasts are projected to be exposed to increasing risks, including coastal erosion, due to climate change and sea level rise. The effect will be exacerbated by increasing human-induced pressures on coastal areas (very high confidence). {WGII 6.3, 6.4, SPM}
By the 2080s, many millions more people than today are projected to experience floods every year due to sea level rise. The numbers affected will be largest in the densely populated and low-lying megadeltas of Asia and Africa while small islands are especially vulnerable (very high confidence). {WGII 6.4, 6.5, Table 6.11, SPM}

As you can see, new trade routes are not mentioned. Based on this, I think that mentioning the opening of new trade routes is biased.

Polar regions from the IPCC Synthesis report:

The main projected biophysical effects are reductions in thickness and extent of glaciers, ice sheets and sea ice, and changes in natural ecosystems with detrimental effects on many organisms including migratory birds, mammals and higher predators. {WGII 15.4, SPM}
For human communities in the Arctic, impacts, particularly those resulting from changing snow and ice conditions, are projected to be mixed. {WGII 15.4, SPM}
Detrimental impacts would include those on infrastructure and traditional indigenous ways of life. {WGII 15.4, SPM}
In both polar regions, specific ecosystems and habitats are projected to be vulnerable, as climatic barriers to species invasions are lowered. {WGII 15.4, SPM}

As you can see, new trade routes are not mentioned. Based on this, I think that mentioning the opening of new trade routes is biased.

From the IPCC Synthesis report "Industry, settlements and society:"

The most vulnerable industries, settlements and societies are generally those in coastal and river flood plains, those whose economies are closely linked with climate-sensitive resources and those in areas prone to extreme weather events, especially where rapid urbanisation is occurring. {WGII 7.1, 7.3, 7.4, 7.5, SPM}
Poor communities can be especially vulnerable, in particular those concentrated in high-risk areas.

As you can see, new trade routes are not mentioned. Based on this, I think that mentioning the opening of new trade routes is biased.

My conclusion is that mentioning new trade routes is biased. It is biased in terms of its socio-economic effects being small relative to other socio-economic effects that are not mentioned. This is implied by the IPCC Synthesis Report's complete omission of the topic. Enescot (talk) 19:59, 15 March 2010 (UTC)[reply]

IMO, most or all of this suggested material is perhaps better suited for consideration at Effects_of_global_warming. No objection to trying some of the suggested condensations, but please try it one point at a time so the many participants have a chance to respond point by point. ... Kenosis (talk) 19:06, 18 March 2010 (UTC)[reply]

Okay. I suggest this change in how the article summarizes health impacts:

Proposed revision (changes in bold):

[...] A 2001 report by the IPCC suggests that glacier retreat, ice shelf disruption such as that of the Larsen Ice Shelf, sea level rise, changes in rainfall patterns, and increased intensity and frequency of extreme weather events are attributable in part to global warming.[64] Other expected effects include water scarcity in some regions and increased precipitation in others, and changes in mountain snowpack.[65]

Social and economic effects of global warming may be exacerbated by growing population densities in affected areas. It is expected that the health benefits of climate change (e.g., fewer deaths from cold exposure) will be outweighed by negative health effects (e.g., increased levels of malnutrition), especially in developing countries. A summary of probable effects and recent understanding can be found in the IPCC Fourth Assessment Report. According to this report, there is observational evidence for an increase in intense tropical cyclone activity [...]

Additional expected effects include sea level rise of 0.18 to 0.59 meters (0.59 to 1.9 ft) in 2090–2100 relative to 1980–1999,[3] new trade routes resulting from arctic shrinkage,[67] possible thermohaline circulation slowing, increasingly intense, in some locations, (but less frequent) hurricanes [68]and extreme weather events,[69] reductions in the ozone layer, changes in agriculture yields, and ocean oxygen depletion.[...]

Ref: [3]

Enescot (talk) 23:33, 19 March 2010 (UTC)[reply]

Impacts on ecosystems

Present revision:

[...] Increased atmospheric CO2 increases the amount of CO2 dissolved in the oceans.[73] CO2 dissolved in the ocean reacts with water to form carbonic acid, resulting in ocean acidification. Ocean surface pH is estimated to have decreased from 8.25 near the beginning of the industrial era to 8.14 by 2004,[74] and is projected to decrease by a further 0.14 to 0.5 units by 2100 as the ocean absorbs more CO2.[3][75] Heat and carbon dioxide trapped in the oceans may still take hundreds of years to be re-emitted, even after greenhouse gas emissions are eventually reduced.[8] Since organisms and ecosystems are adapted to a narrow range of pH, this raises extinction concerns and disruptions in food webs.[76] One study predicts 18% to 35% of a sample of 1,103 animal and plant species would be extinct by 2050, based on future climate projections.[77] However, few mechanistic studies have documented extinctions due to recent climate change,[78] and one study suggests that projected rates of extinction are uncertain.[79]

Compare with the IPCC Synthesis report [4]:

The resilience of many ecosystems is likely to be exceeded this century by an unprecedented combination of climate change, associated disturbances (e.g. flooding, drought, wildfire, insects, ocean acidification) and other global change drivers (e.g. land-use change, pollution, fragmentation of natural systems, over-exploitation of resources). {WGII 4.1-4.6, SPM}
Over the course of this century, net carbon uptake by terrestrial ecosystems is likely to peak before mid-century and then weaken or even reverse[16], thus amplifying climate change. {WGII 4.ES, Figure 4.2, SPM}
Approximately 20 to 30% of plant and animal species assessed so far are likely to be at increased risk of extinction if increases in global average temperature exceed 1.5 to 2.5°C (medium confidence). {WGII 4.ES, Figure 4.2, SPM}
For increases in global average temperature exceeding 1.5 to 2.5°C and in concomitant atmospheric CO2 concentrations, there are projected to be major changes in ecosystem structure and function, species’ ecological interactions and shifts in species’ geographical ranges, with predominantly negative consequences for biodiversity and ecosystem goods and services, e.g. water and food supply. {WGII 4.4, Box TS.6, SPM}

Main differences

The article is biased towards certain topics
- ocean acidification
- projections of extinctions
- uncertainty in these projections
Uncertainty is poorly treated

Article:

Since organisms and ecosystems are adapted to a narrow range of pH, this raises extinction concerns and disruptions in food webs.[76]

"raises extinction concerns" is vague. Table 19.1 of the IPCC Working Group II report states [5]:

Ocean acidification already occurring, increasing further as atmospheric CO2 concentration increases ***; ecological changes are potentially severe *

"ecological changes are potentially severe *" is given a confidence level (* = medium confidence). This is more useful than stating that ocean acidification "raises extinction concerns". The current sentence in the article could be replaced with (in bold):

[...] Increased atmospheric CO2 increases the amount of CO2 dissolved in the oceans.[73] CO2 dissolved in the ocean reacts with water to form carbonic acid, resulting in ocean acidification. Ocean surface pH is estimated to have decreased from 8.25 near the beginning of the industrial era to 8.14 by 2004,[74] and is projected to decrease by a further 0.14 to 0.5 units by 2100 as the ocean absorbs more CO2.[3][75] Heat and carbon dioxide trapped in the oceans may still take hundreds of years to be re-emitted, even after greenhouse gas emissions are eventually reduced.[8] Schneider and others (2007) concluded, with medium confidence, that ecological changes due to ocean acidification would potentially be severe. [...]

A shorter, less precise sentence is:

The ecological impacts of ocean acidification are potentially severe.

Article:

(i) One study predicts 18% to 35% of a sample of 1,103 animal and plant species would be extinct by 2050, based on future climate projections.[77] (ii) However, few mechanistic studies have documented extinctions due to recent climate change,[78] and one study suggests that projected rates of extinction are uncertain.

Sentence (i) is similar to this bit in the Synthesis report:

Approximately 20 to 30% of plant and animal species assessed so far are likely to be at increased risk of extinction if increases in global average temperature exceed 1.5 to 2.5°C (medium confidence). {WGII 4.ES, Figure 4.2, SPM}

Note that this is only given medium confidence, whereas other impacts are high confidence. I suggest that this sentence is deleted and replaced with something which has a higher level of confidence attached to it. The most obvious, and perhaps arbitrary thing to do, would be to refer to the first thing the Synthesis report states about ecosystems. This is:

The resilience of many ecosystems is likely to be exceeded this century by an unprecedented combination of climate change, associated disturbances (e.g. flooding, drought, wildfire, insects, ocean acidification) and other global change drivers (e.g. land-use change, pollution, fragmentation of natural systems, over-exploitation of resources). {WGII 4.1-4.6, SPM}

In this form, it is not very useful, so we can refer to the relevant chapter in the WGII report (chapter 4). From the executive summary (p. 213) [6]:

During the course of this century the resilience of many ecosystems (their ability to adapt naturally) is likely to be exceeded by an unprecedented combination of change in climate, associated disturbances (e.g., flooding, drought, wildfire, insects, ocean acidification) and in other global change drivers (especially land-use change, pollution and over-exploitation of resources), if greenhouse gas emissions and other changes continue at or above current rates (high confidence).

By 2100, ecosystems will be exposed to atmospheric CO2 levels substantially higher than in the past 650,000 years, and global temperatures at least among the highest of those experienced in the past 740,000 years (very high confidence) [4.2, 4.4.10, 4.4.11; Jansen et al., 2007]. This will alter the structure, reduce biodiversity and perturb functioning of most ecosystems, and compromise the services they currently provide (high confidence) [4.2, 4.4.1, 4.4.2-4.4.9, 4.4.10, 4.4.11, Figure 4.4, Table 4.1]. Present and future land-use change and associated landscape fragmentation are very likely to impede species’ migration and thus impair natural adaptation via geographical range shifts (very high confidence) [4.1.2, 4.2.2, 4.4.5, 4.4.10].

I think the best thing to take from this is this part:

By 2100, ecosystems will be exposed to atmospheric CO2 levels substantially higher than in the past 650,000 years, and global temperatures at least among the highest of those experienced in the past 740,000 years (very high confidence) [4.2, 4.4.10, 4.4.11; Jansen et al., 2007]. This will alter the structure, reduce biodiversity and perturb functioning of most ecosystems, and compromise the services they currently provide (high confidence)

This could be condensed down to:

Global warming is expected to result in reduced biodiversity of ecosystems.

Incorporated into the existing revision:

[...] Increased atmospheric CO2 increases the amount of CO2 dissolved in the oceans.[73] CO2 dissolved in the ocean reacts with water to form carbonic acid, resulting in ocean acidification. Ocean surface pH is estimated to have decreased from 8.25 near the beginning of the industrial era to 8.14 by 2004,[74] and is projected to decrease by a further 0.14 to 0.5 units by 2100 as the ocean absorbs more CO2.[3][75] Heat and carbon dioxide trapped in the oceans may still take hundreds of years to be re-emitted, even after greenhouse gas emissions are eventually reduced.[8] Since organisms and ecosystems are adapted to a narrow range of pH, this raises extinction concerns and disruptions in food webs.[76]

Global warming is expected to result in reduced biodiversity of ecosystems. Few mechanistic studies have documented extinctions due to recent climate change,[78] and one study suggests that projected rates of extinction are uncertain.[79]

I think this revision is preferable to the earlier one because the new sentence is based on a high confidence statement, rather than a statement of uncertain confidence.

Sentence (ii)

(i) One study predicts 18% to 35% of a sample of 1,103 animal and plant species would be extinct by 2050, based on future climate projections.[77] (ii) However, few mechanistic studies have documented extinctions due to recent climate change,[78] and one study suggests that projected rates of extinction are uncertain.

Sentence (ii) can be broken down into two parts:

However, (a) few mechanistic studies have documented extinctions due to recent climate change,[78] and (b) one study suggests that projected rates of extinction are uncertain.

(a) is a comment on observed effects of climate change, (b) is a comment on extinction projections. Starting with (a), lets refer back to the IPCC Synthesis report [7]:

Observational evidence[4] from all continents and most oceans shows that many natural systems are being affected by regional climate changes, particularly temperature increases. {1.2}

Changes in snow, ice and frozen ground have with high confidence increased the number and size of glacial lakes, increased ground instability in mountain and other permafrost regions and led to changes in some Arctic and Antarctic ecosystems. {1.2}

There is high confidence that some hydrological systems have also been affected through increased runoff and earlier spring peak discharge in many glacier- and snow-fed rivers and through effects on thermal structure and water quality of warming rivers and lakes. {1.2}

In terrestrial ecosystems, earlier timing of spring events and poleward and upward shifts in plant and animal ranges are with very high confidence linked to recent warming. In some marine and freshwater systems, shifts in ranges and changes in algal, plankton and fish abundance are with high confidence associated with rising water temperatures, as well as related changes in ice cover, salinity, oxygen levels and circulation. {1.2}

Of the more than 29,000 observational data series, from 75 studies, that show significant change in many physical and biological systems, more than 89% are consistent with the direction of change expected as a response to warming (Figure SPM.2). However, there is a notable lack of geographic balance in data and literature on observed changes, with marked scarcity in developing countries.

As you can see, the IPCC Synthesis report cites evidence for observed impacts, yet the article only concentrates on observations in one particular area. I think this is biased. To correct this, I suggest that the highest confidence statement from the Synthesis report replaces part (a) of the sentence. The highest confidence statement made is:

In terrestrial ecosystems, earlier timing of spring events and poleward and upward shifts in plant and animal ranges are with very high confidence linked to recent warming.

My suggested revision is:

In terrestrial ecosystems, evidence for recent warming includes the earlier timing of spring events, and poleward and upward shifts in plant and animal ranges.

Incorporated into the existing article revision:

Additional anticipated effects include sea level rise of 0.18 to 0.59 meters (0.59 to 1.9 ft) in 2090–2100 relative to 1980–1999,[3] new trade routes resulting from arctic shrinkage,[67] possible thermohaline circulation slowing, increasingly intense, in some locations, (but less frequent) hurricanes [68]and extreme weather events,[69] reductions in the ozone layer, changes in agriculture yields, changes in the range of climate-dependent disease vectors,[70] which have been linked to increases in the prevalence of malaria and dengue fever,[71] and ocean oxygen depletion.[72] Increased atmospheric CO2 increases the amount of CO2 dissolved in the oceans.[73] CO2 dissolved in the ocean reacts with water to form carbonic acid, resulting in ocean acidification. Ocean surface pH is estimated to have decreased from 8.25 near the beginning of the industrial era to 8.14 by 2004,[74] and is projected to decrease by a further 0.14 to 0.5 units by 2100 as the ocean absorbs more CO2.[3][75] Heat and carbon dioxide trapped in the oceans may still take hundreds of years to be re-emitted, even after greenhouse gas emissions are eventually reduced.[8] Since organisms and ecosystems are adapted to a narrow range of pH, this raises extinction concerns and disruptions in food webs.[76]

In terrestrial ecosystems, evidence for recent warming includes the earlier timing of spring events, and poleward and upward shifts in plant and animal ranges. One study predicts 18% to 35% of a sample of 1,103 animal and plant species would be extinct by 2050, based on future climate projections.[77] One study suggests that projected rates of extinction are uncertain.[79]

I think this revision is an improvement on the previous revision because it is not biased towards non-detection of climate change, and it is a based on a finding the IPCC made with very high confidence.

Part (b) of the sentence:

However, (a) few mechanistic studies have documented extinctions due to recent climate change,[78] and (b) one study suggests that projected rates of extinction are uncertain.

Referring back to the IPCC Synthesis report, it does not mention "projected rates of extinction". Therefore I think mention of this is biased. Part (b) is also vague. It states that:

projected rates of extinction are uncertain.

This is meaningless without specifying what the nature of the uncertainty is. To conclude:

The choice of subject for part (b) of the sentence is arbitrary. The fact that it is not mentioned in the IPCC Synthesis report makes me think that it is relatively unimportant compared to other topics regarding ecosystems.
It is vague, perhaps to the point of being meaningless

Replacement

If we have to have something on projections of ecosystem extinctions, it would make sense for the magnitude of extinction plus the uncertainty of the projection to stated. I think magnitude of extinction is more important than the rate of extinction since the IPCC Synthesis report mentions a magnitude estimate:

Approximately 20 to 30% of plant and animal species assessed so far are likely to be at increased risk of extinction if increases in global average temperature exceed 1.5 to 2.5°C (medium confidence). {WGII 4.ES, Figure 4.2, SPM}

This also has a confidence level attached to it. In the existing revision, we already have a magnitude estimate of extinctions:

(i) One study predicts 18% to 35% of a sample of 1,103 animal and plant species would be extinct by 2050, based on future climate projections.[77] (ii) However, few mechanistic studies have documented extinctions due to recent climate change,[78] and one study suggests that projected rates of extinction are uncertain.

No confidence level is attached to the projection, but he Synthesis report includes a confidence level.

Suggested change

For this, I think it's helpful to look at the IPCC report chapter the Synthesis report is referring to (Chapter 4, WGII):

Approximately 20 to 30% of plant and animal species assessed so far (in an unbiased sample) are likely to be at increasingly high risk of extinction as global mean temperatures exceed a warming of 2 to 3°C above preindustrial levels (medium confidence) [4.4.10, 4.4.11, Figure 4.4, Table 4.1].

Projected impacts on biodiversity are significant and of key relevance, since global losses in biodiversity are irreversible (very high confidence) [4.4.10, 4.4.11, Figure 4.4, Table 4.1]. Endemic species richness is highest where regional palaeoclimatic changes have been muted, providing circumstantial evidence of their vulnerability to projected climate change (medium confidence) [4.2.1]. With global average temperature changes of 2°C above pre-industrial levels, many terrestrial, freshwater and marine species (particularly endemics across the globe) are at a far greater risk of extinction than in the recent geological past (medium confidence) [4.4.5, 4.4.11, Figure 4.4, Table 4.1]. Globally about 20% to 30% of species (global uncertainty range from 10% to 40%, but varying among regional biota from as low as 1% to as high as 80%) will be at increasingly high risk of extinction, possibly by 2100, as global mean temperatures exceed 2 to 3°C above pre-industrial levels [4.2, 4.4.10, 4.4.11, Figure 4.4, Table 4.1]. Current conservation practices are generally poorly prepared to adapt to this level of change, and effective adaptation responses are likely to be costly to implement (high confidence) [4.4.11, Table 4.1, 4.6.1].

My suggested revision is:

If global mean temperatures exceed 2 to 3°C above pre-industrial levels, around 20 to 30% of species might be at increased risk of extinction, possibly by 2100.

In many ways, this is an unsatisfactory revision. It is less specific than the IPCC report, but it's the best I can do without writing another few sentences. I chose to say "might be at increased risk of extinction" because the IPCC report only has medium confidence in the projection. Additionally, my sentence does not actually refer to the fact that the figure is derived from the "species assessed so far". The fact that Fischlin et al. mentioned this is no doubt significant. So by using the word "might", I hope to give some indication of the uncertainties surrounding this projection.

Here is this new revision integrated into the existing revision:

Additional anticipated effects include sea level rise of 0.18 to 0.59 meters (0.59 to 1.9 ft) in 2090–2100 relative to 1980–1999,[3] new trade routes resulting from arctic shrinkage,[67] possible thermohaline circulation slowing, increasingly intense, in some locations, (but less frequent) hurricanes [68]and extreme weather events,[69] reductions in the ozone layer, changes in agriculture yields, changes in the range of climate-dependent disease vectors,[70] which have been linked to increases in the prevalence of malaria and dengue fever,[71] and ocean oxygen depletion.[72] Increased atmospheric CO2 increases the amount of CO2 dissolved in the oceans.[73] CO2 dissolved in the ocean reacts with water to form carbonic acid, resulting in ocean acidification. Ocean surface pH is estimated to have decreased from 8.25 near the beginning of the industrial era to 8.14 by 2004,[74] and is projected to decrease by a further 0.14 to 0.5 units by 2100 as the ocean absorbs more CO2.[3][75] Heat and carbon dioxide trapped in the oceans may still take hundreds of years to be re-emitted, even after greenhouse gas emissions are eventually reduced.[8] Since organisms and ecosystems are adapted to a narrow range of pH, this raises extinction concerns and disruptions in food webs.[76]

If global mean temperatures exceed 2 to 3°C above pre-industrial levels, around 20 to 30% of species might be at increased risk of extinction, possibly by 2100. However, few mechanistic studies have documented extinctions due to recent climate change,[78] and one study suggests that projected rates of extinction are uncertain.[79]

As you can see, it's a swap of the previous sentence with my new one:

Old

(i) One study predicts 18% to 35% of a sample of 1,103 animal and plant species would be extinct by 2050, based on future climate projections.[77]

New

If global mean temperatures exceed 2 to 3°C above pre-industrial levels, around 20 to 30% of species might be at increased risk of extinction, possibly by 2100.

I think that it is better to use the IPCC report instead of an individual paper
It is a more important projection – it applies to all species rather than just the sample in the cited study.
It specifically relates impacts to global mean temperature
It gives some impression of projection uncertainty.

Further comment on sentences (i) and (ii)

(i) One study predicts 18% to 35% of a sample of 1,103 animal and plant species would be extinct by 2050, based on future climate projections.[77] (ii) However, (I) few mechanistic studies have documented extinctions due to recent climate change,[78] and (II) one study suggests that projected rates of extinction are uncertain.

The word "however" links sentence (i) to sentence (ii). This implies that subject (I) has an affect on the study in sentence (i). Subject (I) has to do with attributing observed extinctions to climate change. Sentence (i) is about future extinctions. The linking of the two sentences with the word "however" suggests that subject (I) has a negative bearing on the validity of the previous sentence.

To see if this is the case, it is worth checking the study referred to in sentence (i). This is a study by Thomas et al (2004) pdf. Referring to the later section of the paper on uncertainties in projections:

Many unknowns remain in projecting extinctions, and the values provided here should not be taken as precise predictions. Analyses need to be repeated for larger samples of regions and taxa, and the selection of climate change scenarios need to be standardized. Some of the most important uncertainties follow (see also Supplementary Information). We estimate proportions of species committed to future extinction as a consequence of climate change over the next 50 years, not the number of species that will become extinct during this period. Information is not currently available on time lags between climate change and species-level extinctions, but decades might elapse between area reduction (from habitat loss) and extinction14. Land use should also be incorporated into analyses: extinction risks might be higher than we project if future locations of suitable climate do not coincide with other essential resources (such as soil type or food resources). There is also uncertainty over which species will inhabit parts of the world projected to have climates for which no current analogue exists6. Equally importantly, all parts of the world will have historically unprecedented CO2 levels6, which will affect plant species and ecosystems21,22 and herbivores23, resulting in novel species assemblages and interactions.

No reference is made to observed extinctions attributed to climate change affecting uncertainty of their projections. Therefore it's worth looking at the source provided to support subject (I). The link to this reference was dead so I've updated it. It refers to a paper by McLaughlin et al (2002). If subject (I) is related to the projection in sentence (i), it should be in this reference. To recap, subject (I) is:

"few mechanistic studies have documented extinctions due to recent climate change"

and was linked to the previous sentence on projections by the word "however". From McLaughlin et al (2002) [8]:

Climate change at global and regional scales is predicted to alter species distributions, life histories, community composition, and ecosystem function (1–5). In particular, population losses caused by climate change threaten both species diversity and the delivery of critical ecosystem services (6). Predictions of climate-induced population extinctions are supported by correlational evidence that numerous species are shifting their ranges in response to climatic warming (7–11). Nevertheless, few mechanistic studies have linked extinctions to recent climate change (12, 13). Furthermore, most climate change research and forecasts focus on shifts in climatic means. Global climate models also predict changes in climatic variability (14, 15), but biotic impacts of those increases have received less study. Here, we report that extinctions of two populations of the checkerspot butterfly, Euphydryas editha bayensis, were caused by a combination of habitat loss and regional climate change in the form of increasing variability in precipitation.

Checking references 12 and 13 does not show the Thomas et al (2004), which is not surprising since McLaughlin et al (2002) is an earlier paper. In my view, the choice of another editor to synthesize sentence (i) with subject (I) is probably acceptable, but I don't think that it's ideal. It would be better to simply restructure sentences (i) and (ii). My suggested change is:

(1) Few mechanistic studies have linked extinctions to recent climate change. (2) One study predicts 18% to 35% of a sample of 1,103 animal and plant species would be extinct by 2050, based on future climate projections. (3) Another study suggests that projected rates of extinction are uncertain.

This avoids the problem of synthesizing the two studies. I should note that as I described earlier, sentences (2) and (3) are problematic. In particular, the third sentence here is weak. It would be better to simply refer to the uncertainties as described by Thomas et al (2004) in their projections, rather than referring to another paper. You can see that this revision still suffers from a synthesis problem with sentences two and three. Sentence three could be interpreted as a negative comment on the validity of the previous sentence. Sentence (3) is poor. It does not specify any comment on the nature of uncertainties in projections.

Subject (II)

To recap:

(i) One study predicts 18% to 35% of a sample of 1,103 animal and plant species would be extinct by 2050, based on future climate projections.[77] (ii) However, (I) few mechanistic studies have documented extinctions due to recent climate change,[78] and (II) one study suggests that projected rates of extinction are uncertain.

In a similar fashion to subject (I), subject (II) could also be read as a negative comment on the validity of sentence (i). It could therefore also suffer from the problem of improper synthesis. Subject (II) is based on a paper by Botkin et al (2007) pdf. It refers to the Thomas et al. (2004) and does describe areas of uncertainty in this paper. Its inclusion is therefore valid. Still, I would prefer it if the "however" link is removed.

Thomas et al (2004) do comment on uncertainties in their projections. The editor who structured sentences (i) and (ii) did attempt to covey they uncertainties over these projections. I think there's room for improvement:

(1) Few mechanistic studies have documented extinctions due to recent climate change. (2) One study predicts 18% to 35% of a sample of 1,103 animal and plant species would be extinct by 2050, based on future climate projections. (3) These types of studies do, however, have limitations.

This revision I think is more logical. It preserves the chronological order of the papers. It is also logical in the sense that observations are first commented on, followed by projections of future changes, followed by a comment on projections. Despite this, I think that this is still a weak improvement.

Sentence (3):

These types of studies do, however, have limitations.

is I feel a very minor improvement on:

[...] one study suggests that projected rates of extinction are uncertain.

Sentence (3) is based on the abstract of the paper by Botkin et al (2007), where it is stated that:

The demand for accurate forecasting of the effects of global warming on biodiversity is growing, but current methods for forecasting have limitations.

Summary

Overall I think that reference to the papers by McLaughlin et al (2002), Thomas et al (2004), and Botkin et al (2007) is not justified. The article at present is biased towards ecosystem projections and non-attribution of ecosystem impacts (extinctions). References to the stated papers, in my view, is not justified. Selection appears to be arbitrary and the failure to refer to the literature assessment by Fischlin et al (2007) is not acceptable. The choice made by editors of the article to focus on attribution of extinctions and projections of extinctions is biased because:

non-attribution is not as noteworthy as attribution.
The section is biased towards non-attribution, e.g., the literature assessment by Rosenzweig et al. (2007) is not mentioned [9]. This also applies to physical attribution [10].

Overall, the section's coverage of attribution studies is poor, and that applies to the area of ecosystems. Uncertainty is treated very poorly. Enescot (talk) 00:00, 17 March 2010 (UTC)[reply]

IMO, most or all of the suggested additions in the lengthy sections here and further above are perhaps better suited for consideration at Effects_of_global_warming. Please see also WP:Summary style and the essay WP:TLDR. I have no objection to trying some of the suggested condensations of points that arguably are too detailed or wordy at present. On a quick reading of the above, I think the suggested changes of wording are largely unnecessary. Of course there's always room for further improvements to articles. Why not take it one point at a time and see what the response is from the many editors who pitch in on this article?. ... Kenosis (talk) 19:10, 18 March 2010 (UTC)[reply]

GISS update

NASA: “It is nearly certain that a new record 12-month global temperature will be set in 2010″ « Climate Progress gives interesting information from an email written by Hansen, with a link to the full draft paper. Hansen also describes the misuse of FOIA requests and their effects. Statisticians reject global cooling - Environment- msnbc.com and Global cooling bites the dust: Hottest January followed by second hottest February. Now March is busting out. « Climate Progress also provide relevant information. . . dave souza, talk 10:44, 20 March 2010 (UTC)[reply]

~~It is too soon to include this. This is just a prediction. Let's stick with facts. Task Force B (talk) 02:34, 21 March 2010 (UTC)~~[confirmed scibaby sock Kim D. Petersen (talk)][reply]

It is WAY too soon! Hansen has just circulated his draft of the paper for comments and has not yet identified a journal for publication. While holding skeptics to a nebulous 'wait and see' for inclusion of material from publications in refereed journals, disciples of AGW want to rush to the fore in Wikipedia with pre-publication material flattering to their biases. Hardly a pattern for cogent treatment of a controversial subject!Dikstr (talk) 00:09, 22 March 2010 (UTC)[reply]

Agree, worth waiting for definitive figures either way, just an update that seemed worth noting on the talk page. . . dave souza, talk 02:21, 22 March 2010 (UTC)[reply]

To clarify for the benefit of Dikstr, Q22 applies to this paper even more than it would to a published paper. It doesn't matter who proposes its inclusion. We can afford to wait for the global average temperature for 2010 to be calculated after the measurements have been collected. Also, as previously noted, the temperature of any given year doesn't count for much. This article is about the rising trend over time, not years in which the global average temperatures set a record (albeit the latter occurrence is a predictable corollary of the former). Tasty monster (=TS ) 07:44, 22 March 2010 (UTC)[reply]

Solar Variation

OK. Lets discuss my recommended alteration of the 1st paragraph of the Global Warming/Solar Variation section:

"Variations in solar output have been the cause of past climate changes.[46] Although solar forcing is estimated by climate models to be a minor component of global warming in recent decades,[47] recent research indicates a larger role comparable to that of anthropogenic greenhouse gas accumulation.[48]"

This seems like an eminently fair description of the current knowledge of the subject. And if you claim that ref 48 is an 'outlier' paper you'd better be prepared to justify it! References 46 - 48 are:

Solar Influences On Global Change, National Research Council, National Academy Press, Washington, D.C., isbn=0-309-05148-7, page=36

Hansen, J., et. al., Efficacy of climate forcings (2005),Journal of Geophysical Research, v.110|pages=D18104

Scafetta, N., Empirical analysis of the solar contribution to global mean air surface temperature change, Journal of Atmospheric and Solar-Terrestrial Physics (2009), doi:10.1016/j.jastp.2009.07.007 Dikstr (talk) 23:37, 22 March 2010 (UTC)[reply]

46-48 should be 3 papers. Do you miss something? --Stephan Schulz (talk) 23:43, 22 March 2010 (UTC)[reply]

No you did. I've put dots in front of them to make it easier for you.Dikstr (talk) 00:01, 23 March 2010 (UTC)[reply]

RealClimate: Please, show us your code . . dave souza, talk 09:37, 23 March 2010 (UTC)[reply]

Would you care to expand on the significance of this blog site statement?Dikstr (talk) 18:20, 23 March 2010 (UTC)[reply]

It could have something to do with reference #1 which uses (amongst others) the Friis-Christensen & Lassen paper, which is discussed in the Realclimate posting. Why we are using a very old reference from 1994 is beyond my understanding (the NRC book) - since a lot of things have happened since that time. (this has been raised several times on Talk:Solar variation btw. It is extremely misleading to use an assessment from 1994 when we have newer assessments that draw upon expanded and more complete data and research. --Kim D. Petersen (talk) 19:02, 23 March 2010 (UTC)[reply]

Unless you're prepared to discuss specific findings that refute those of the 1994 NRC publication your objection to using 'older' publications is just POV posturingDikstr (talk) 19:10, 23 March 2010 (UTC)[reply]

That is not the purpose of Wikipedia - there are several newer assessments - two at least by the IPCC (the TAR and the AR4). Several assessment papers (one of these is mentioned below). I see no reason to use a 1994 publication, especially since the TSI record, as well as the proxy record, has grown significantly since that time, and not least that papers it is based upon (F-C&L) have been obsoleted and shown erroneous. You are attempting to reverse the burden here - you in fact are the person who has to defend using an old assessment instead of the newer ones. --Kim D. Petersen (talk) 20:52, 23 March 2010 (UTC)[reply]

RealClimate: Please, show us your code is of course a WP:SPS giving the expert views of Rasmus E. Benestad and an update of discussions following his joint paper (Benestad and Schmidt 2009) regarding problems with Scafetta's papers. These issues are further analysed in Lockwood 2010 Solar change and climate: an update in the light of the current exceptional solar minimum which notes problems with use of the ACRIM TSI composite based on the application of an entirely inappropriate TSI reconstruction, multivariate fits resulting in dramatically reduced significance (unstated by Scafetta) and the analysis of Scafetta (2009) requiring an amplification of the solar input by a factor of 13.5 which Scafetta fails to explain or justify. Lockwood concludes that "the popular idea (at least on the Internet and in some parts of the media) that solar changes are some kind of alternative to GHG forcing in explaining the rise in surface temperatures has no credibility with almost all climate scientists." In a more recent posting, Benestad discusses More on sun-climate relations citing several new papers to conclude that "changes in the sun play a minor role in climate change on decadal to centennial scales. After all, 2009 was the second-warmest year on record, and by far the warmest in the southern hemisphere, despite the record solar minimum. The solar signal for the past 25 years is not just small but negative (i.e. cooling), but this has not noticeably slowed down global warming. But there are also many unknowns remaining". . . dave souza, talk 22:03, 23 March 2010 (UTC)[reply]

Solar variation, models, and Scafetta

If we want to be finicky, essentially everything we use to make scientific statement is "a model". But the influence of solar variations had been analysed using many different models, both so simple that most people won't recognise them as models, and full scale GCMs (Boris correct me if I speak nonsense ;-). Scafetta is a real outlier with a history of papers that fail to find much support in the scientific community. See Talk:Global_warming/FAQQ22. --Stephan Schulz (talk) 23:20, 22 March 2010 (UTC)[reply]

You're not well informed regarding Scafetta's work or you'd not be consistently misspelling his name. Scafetta's work has been published in refereed journals. Unless you can cite specific refereed publications that argue convincingly against his methods and results then your opinion lacks credibility comparable to Scafetta's work.Dikstr (talk) 00:03, 23 March 2010 (UTC)[reply]

This is such a violation of WP:UNDUE it's not funny. If the theory ever gains widespread support within the scientific community, we can include it, but until then, it's an outlier and nothing more. StuartH (talk) 23:54, 22 March 2010 (UTC)[reply]

You need to re-read WP:UNDUE. Your characterization is incorrect.Dikstr (talk) 00:36, 23 March 2010 (UTC)[reply]

For starters, if one looks at Scafetta's papers with a technical eye that has any reasonable balance w.r.t. reasonable conclusions that might merit consideration in a GW summary article such as this, it's clear his assertions about GW are outliers as other WP editors here have said. Most of what Scafetta has said in his published work has to do with measurement and analysis of solar variation. with no evidence of any serious incentive on the part of researchers in the same community as that of Sarfetta to either respond or confirm his work. Whether or not it will ultimately have been taken seriously in the very small community of researchers that focus upon solar variation per se remains to be seen. Some, or perhaps even much, of what Scafetta has published may well merit incorporation in certain very limited ways into e.g. the article on Solar variation. IMO.
As to Scafetta and West (2007) and Scafetta and Wilson (2009), they do not merit inclusion in this summary article on GW, at least for the following reasons: In the abstracts and conclusions of published research papers, both sections of which researchers are normally granted wide liberty by academic and scientific research communities to speculate about the implications of what their data analyses might mean for their readers with little or no serious danger of being discredited for purely technical ineptness, Scafetta, West and Wilson respectively make their personal conclusory arguments. For example:
In Scafetta and West 2007, "Phenomenological reconstructions of the solar signature in the Northern Hemisphere surface temperature records since 1600", In the abstract the authors suggest a scenario that they, and they alone or pretty-much alone in the research community have put forward to date, then say that under this scenario the Sun might have contributed up to approximately 50% (or more if ACRIM total solar irradiance satellite composite [Willson and Mordvinov, 2003] is implemented) of the observed global warming since 1900.
....... Going forward a couple years, in Scafetta and Wilson 2009, ACRIM-gap and Total Solar Irradiance (TSI) trend issue resolved using a surface magnetic flux TSI proxy model.
In the Abstract:

Both ‘mixed’ composites demonstrate a significant TSI increase of 0.033 %/decade between the solar activity minima of 1986 and 1996, comparable to the 0.037 % found in the ACRIM composite.

In the conclusion the authors say:

"Within the uncertainty of the model we have concluded that the data support the view that TSI increased significantly (by about 0.033 %) between the successive solar minima of 1986 and 1996, confirming the trend found by the ACRIM TSI composite and contradicting the absence of a TSI trend in the PMOD and the KBS07 proxy model."

and

"a corrected KBS07 proxy model is expected to reproduce the upward trend of the ACRIM TSI composite between the 1986 and 1996 TSI minima."

and

"This finding has evident repercussions for climate change and solar physics. Increasing TSI between 1980 and 2000 could have contributed significantly to global warming during the last three decades. [Scafetta and West, 2007, 2008] Current climate models [IPCC 2007] have assumed that the TSI did not vary significantly during the last 30 years and have therefore underestimated the solar contribution and overestimated the anthropogenic contribution to global warming."

Note that in 2007, Scafetta and Wilson asserted that there could be under their scenario as much as a 50% underestimate of the non-anthropogenic contribution to present-day global warming. By 2009, the assertion had become that "Within the uncertainty of the model we have concluded that the data support the view that TSI increased significantly (by about 0.033 %) between the successive solar minima of 1986 and 1996, confirming the trend found by the ACRIM TSI composite and contradicting the absence of a TSI trend [deduced by two of the methods considered by the IPCC]."
....... Note that the 0.033% difference in total TSI between the IPCC estimates and Scafetta and Wilson's estimate equivalent to 0.00033 of the TSI estimate. They call it "significant", but by what statistical standards is quite unclear. This is rather unlike the IPCC whose statistical standards are also somewhat unclear to us when they say things like "95% confidence level", but which appears to be far more cautious than Scafetta about calling things significant, if for no other reason than that Scafetta has no one else to account for other than Wilson and West in person, the rest of the research community evidently content to regard them as outliers since there doesn't appear to me to be either much follow-up work or much response except for some criticisms of his "methods").
....... More important, IMO at least, is the fact that in two years Scafetta has in his arguably very liberal published conclusion sections gone from saying "up to 50% or more, if ..)" of GW is natural varialtions of the Sun, to saying that 0.0003 of TSI within an undefined confidence level,
Stranger yet to me at least, is that after we jettison all the technical jargon, Sacafetta asserted in his 2007 paper that there is a delay of several decades in the effects of TSI in having a measurable impact of forcing within key components of the troposphere and subsstrates, yet making such sweeping conclusions about AGW. To me at least, it's not surprising that in the four-years-or more-since Scafetta began to publish his empirical conclusions with radical speculations in the abstract and conclusion sections (both of which are written by the authors of the papers) that other researchers worldwide had pretty-much chosen not to even bother to respond.
....... Speaking of course as only one WP editor, I completely agree with the other editors who have rejected Scafetta's material on solar forcing due to issues of WP:WEIGHT. Further, according to the policy WP:PSTS we're to avoid including primary source material in the following way:

Any interpretation of primary source material requires a reliable secondary source for that interpretation. A primary source can be used only to make descriptive statements that can be verified by any educated person without specialist knowledge. [bold emphasis mine]

Not only are Scafetta's conclusions highly doubtful for inclusion in this particular article by WP:WEIGHT , to me they're clearly out of bounds w.r.t. WP:PSTS (part of the core content policy WP:NOR). While I'm not intractably stuck on resisting the inclusion of Scafetta's material in this particular article, to date at least, it seems clear to me that his conclusions and abstracts to date have insufficient weight within the scientific community to merit much of a published response, and that the proposed inclusion of his conclusory statements does not come anywhere close to meeting the standard set by WP:NOR. ... Kenosis (talk) 04:23, 23 March 2010 (UTC)[reply]

Follow-up: Is the above comment WP:TLDR about what should have been a very minor issue? Here's cutting to the chase, IMO. Scafetta'set al research appears to me to meet WP:V, specifically WP:SOURCES, but doesn't appear to me to meet either WP:NPOV, specifically WP:WEIGHT or WP:NOR, specifically WP:PSTS, in this article. ... Kenosis (talk) 06:55, 23 March 2010 (UTC)[reply]

Kenosis - You start with the subjective statement: "if one looks at Scafetta's papers............." and continue with the "outlier" characterization without any semblance of argument or proof. After exposing your bias the rest is just a ramble without any coherent or salient scientific criticism. Your discussion of the 50% solar forcing versus the 0.033 %/decade TSI rate of change demonstrates that you did not understand Scafetta's work. You might also attempt to spell the names of the authors you're citing correctly - it would give one more confidence in your critical reading abilities.Dikstr (talk) 16:43, 23 March 2010 (UTC)[reply]

LOL. True that it was a good bit of a rant from me last night, hastily composed, sloppy, and which I should have yanked out and more thoroughly recomposed after mistakenly hitting "save" instead of "preview". Anyway, I've been seeing numerous attempts over the last several months to insert sentences into this article based on Scafetta's 2007 and/or his solo 2009 work, conclusory sentences based on Scafetta alone, to the effect that "recent empirical research" has shown that TSI is responsible for a good deal of observed GW, or "phenomenological reconstructions" show that solar forcing is on the rise and is substantially responsible for GW. An example of those many attempts, all by Dikstr, is this edit. So I decided to take a closer look at the articles he's published, and responses to it.
....... Scafetta and West 2007 is an outlier even on the face of it, in Scafetta and West's own words in the abstract and conclusion, hardly a "subjective statement", as you say, which reveals my "bias" as you say. Scafetta and West say they've come up with a composite model which leads them to a conclusion very different than that of the other researchers' models considered by the IPCC (all of which have factored in solar forcing based on the same satellite data set used by Scafetta and Wilson). By pasting together a bunch of other researchers' work into a new model, Scafetta purports to find a whole bunch of increase in solar radiation starting from about 1900 that everyone else seems to have missed, radiation which he and West assert could account for in excess of 50% of the observed GW since 1900. He's acknowledging being an outlier by the very words of his 2007 abstract and conclusion, which amount to saying all those other models the IPCC are using are wrong, and they could have radically underestimated the non-anthropogenic contribution to GW. On the face of it, essentially an intentional position setting one's self up as an outlier. Problem is, of course, that we don't have any measurements of TSI before 1978.
....... His and Wilson's 2009 paper is of course far more technical and tightly focused on the measurement methods of TSI, and concludes a 0.03% per decade increase in TSI between 1986 and 1996, but without necessarily going the extra step and extrapolating this conclusion back into the past when there were no direct measurements of TSI. My point above was not to imply direct equivalence of the conclusions in these two papers, but only that this one is a far more conservative conclusion much more tightly focused on the specific TSI measurements and calculations. And even here, other researchers have analyzed the same information and concluded differently even on this issue of possible changes in solar forcing in this limited time frame.
....... As to the 2007 paper, only Benestad and Schmidt have bothered to respond to date, and they've criticized the methods and conclusions of Scafetta and West specifically, and Scafetta has in turn criticized them. AFAICT, Benestad and Schmidt are to date the only scientific secondary sources about Scafetta's slant on the ACRIM/PMOD debate and how researchers might best extrapolate TSI back to before 1978. Now, if Scafetta 2007 had any merit I'd sure think there would be a stampede of scientific literature attempting to hone in further on what Scafetta and West had to say. But that's not what has happened to date.
....... As to Scafetta's other 2009 paper, I hadn't yet seen it as of last night. In that one he says in the abstract w.r.t. solar forcing "The sun may have caused from a slight cooling, if PMOD TSI composite is used, to a significant warming (up to 65% of the total observed warming) if ACRIM, or other TSI composites are used." In this one he's basically re-analyzed everybody's work, and comes up with a wider range of variability than have others. Fair enough I suppose, except again, if there were merit to these broad assertions of TSI increasing since 1900, made without access to measurements of SI prior to 1978, it seems that there'd be plenty of secondary scientific literature following up post haste. AFAICT, there has not been such a response. ... Kenosis (talk) 20:33, 23 March 2010 (UTC)[reply]

As discussed in the section above, Lockwood's 2010 paper (link below) discusses various problems with Scafetta's papers and with various claims made on the basis of these papers. . . dave souza, talk 22:06, 23 March 2010 (UTC)[reply]

Thanks for the reference. ... Kenosis (talk) 03:36, 24 March 2010 (UTC)[reply]

Have you discussed Solar change and climate: an update in the light of the current exceptional solar minimum — Proceedings A Proc. R. Soc. A 8 February 2010 ? . . . dave souza, talk 13:01, 23 March 2010 (UTC)[reply]

Kenosis: I'll tackle a few of your misstatements (in quotes):

"Scafetta and West 2007 is an outlier even on the face of it.." - A subjective evaluation prior to any discussion. Clearly what follows is just an inadequate attempt to justify your POV.

"Scafetta and West say they've come up with a composite model which leads them to a conclusion very different than that of the other researchers' models considered by the IPCC" - the major climate model results referenced by the IPCC are global circulation models, approximate representations of the complex climate system. Their sensitivity to TSI variation is highly uncertain, as is their ability to predict future climate based on current data and past proxies. Scafetta & West use an empirical analytical technique with current climate/satellite TSI data and past solar proxy and climate data. These methods are vastly different in approach and ability to identify solar climate forcing - a difference you seem to be unaware of.

"(all of which have factored in solar forcing based on the same satellite data set used by Scafetta and Wilson). " - Same satellite date - but very different assumptions regarding sensitivity to solar forcing and computational approach.

"Scafetta purports to find a whole bunch of increase in solar radiation starting from about 1900 that everyone else seems to have missed" - Not true. Virtually every solar proxy modeler has derived similar TSI increase during the industrial era.

"He's acknowledging being an outlier by the very words of his 2007 abstract and conclusion, which amount to saying all those other models the IPCC are using are wrong, and they could have radically underestimated the non-anthropogenic contribution to GW. On the face of it, essentially an intentional position setting one's self up as an outlier. " - Solving a problem using another method and finding different results is a quintessential part of the scientific process. Disagreement does not make an idea an 'outlier'. The bizarre overuse of the term 'outlier' in Wikipedia is a convenient ruse to discredit less popular ideas but irrelevant to their value or accuracy.

"but without necessarily going the extra step and extrapolating this conclusion back into the past when there were no direct measurements of TSI" - WRONG! This is exactly the process used by Scafetta. His approach is validated by satellite data and extrapolated through proxy data to pre-satellite periods. Really - read the papers before criticizing!

"And even here, other researchers have analyzed the same information and concluded differently even on this issue of possible changes in solar forcing in this limited time frame. As to the 2007 paper, only Benestad and Schmidt have bothered to respond to date, and they've criticized the methods and conclusions of Scafetta and West specifically, and Scafetta has in turn criticized them." - Benestad and Schmidt are not the only ones and made some glaring and obvious errors in doing so. See: [11]

"AFAICT, Benestad and Schmidt are to date the only scientific secondary sources about Scafetta's slant on the ACRIM/PMOD debate and how researchers might best extrapolate TSI back to before 1978" - NOT TRUE! See Physics Today Letters for Oct. 2008 and Nov. 2009 Dikstr (talk) 23:14, 23 March 2010 (UTC)[reply]

Dikstr, you've been provided with reliable sources severely criticising Scafetta as being incorrect and being an extreme minority view. Your original research doesn't cut it. . . dave souza, talk 23:28, 23 March 2010 (UTC)[reply]

I have? Name one. Benestad and Schmidt aren't in that category. You're entitled to your opinion on my original research but you need to back it up with specific arguments to achieve any semblance of cogency.Dikstr (talk) 00:58, 24 March 2010 (UTC)[reply]

I find this discussion quite distressing. Why are Wikipedia editors making judgements about which viewpoints to include in an article based on technical analysis of the contents of academic papers? The point of WP:UNDUE is that important minority viewpoints should not be over-represented in articles, not that they shouldn't be mentioned at all. The Scafetta paper is in every way a reliable primary source, whether its contents are actually correct or not. What other topic area on Wikipedia would have editors arguing over whether a peer-reviewed paper can be mentioned in the article or not, based not on an editorial question about improving the article, but on their own original research into the validity of the paper's conclusions? Referencing a paper does not constitute an endorsement of its findings. The paper should be mentioned, in context, in a neutral way, and linked to for the educated reader to make up their own mind - just like it would be in any other topic. Thparkth (talk) 00:43, 24 March 2010 (UTC)[reply]

"Important minority viewpoint"^{[citation needed]}... Ie. your argument would have merit, iff this had been an article about Solar variation and not a top-level article with a summary section. Here the WP:UNDUE gets extreme - because the summary is roughly 1 paragraph, where the Scaffetta paper would get roughly 33%. Outside of that S&W is an outlier - which doesn't come up to significant minority position. And of course it is an editorial judgement, WP can't include everything, everywhere. --Kim D. Petersen (talk) 01:11, 24 March 2010 (UTC)[reply]

Sanctimonious but unconvincing. I note you've avoided joining in the discussion to provide justification for your judgment regarding "doesn't come up to significant minority position".Dikstr (talk) 02:30, 24 March 2010 (UTC)[reply]

That's actually an argument I agree with - an editorial one based on optimizing the usefulness of the article. What I object to is the idea that we can exclude any mention of a peer-reviewed paper because we disagree with its methods and conclusions. Thparkth (talk) 01:15, 24 March 2010 (UTC)[reply]

I don't think it's the methods or conclusions. I just want to know how it's notable. In my opinion, I think Dikstr thinks it's important because it disagrees with the mainstream assessment. What are we writing? An encycolopedic overview for the readers, or an esoteric overbudened section for the writers? I do appreciate Diskr's decision to write rather than edit war, I don't appreciate his persistence and disparagement of the editors. --CaC 04:44, 24 March 2010 (UTC)

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