Talk:Instrumental temperature record

Methodology

I'm looking for the methodology used to calculate global temperature. The sources here seem a little unclear. There's a reference to "There are three main datasets showing analyses of global temperatures", but the description then seems to go on to describe only one set of raw data 78.105.167.241 (talk) 13:25, 12 July 2011 (UTC)

Christy Quote

I added a notable quotation by UAH professor John Christy, a former IPCC lead author regarding the uncertainty of the temperature record due to urbanization, land use and relocation effects. Zoomwsu (talk) 23:34, 16 February 2010 (UTC)

Due to the mangled sentence at the end of the first paragraph in the following subsection, which is referred to as being in conflict, I had downloaded the cited source. This quote from Christy, by my guess. is from 2001 (The Sunday Times clearly hadn't done a recent interview with him). The claim that a lack of metadata makes correction impossible vastly ignores the past decade, including many of the points and cited sources in the paragraphs that immediately followed.

Following the references, including the Sunday Times and names contained therein, to find who made what claims, why and when, I've noticed that the Times article's collection and references are almost bizarre in their presentation. Ross McKitrick, another person in that article has chosen to ignore thermal research of the individual gases that have stood for a century with no research contradicting such things as the thermal capacity and proportion of the atmospheric gases (ignoring increases of carbon therein). His "research" outside of economics consists of incidentals and, again, ignores available research stated in said subsection. Watts, another referred to meta-researcher and meteorologist made the same assumptions and blissfully ignored the follow-up research by the The Journal of Geophysical Research which found the siting claims resulted in a minor bias...towards cooling (available at the end of his own wiki-article). Mills, another economics expert, merely seems to repeat a note about temperatures rising two other times in the last millenium, which skims over the aforementioned physical chemistry research and relative increase in tempuratures (currently, we are exceeding the Medieval Warming Period, something ironically confirmed by said physical chemistry).

I have altogether ignored the Times' bias, and I feel anyone actually using the references in this article could point out the separation of scientific research to this point from claims made by individuals in Economics and a Meteorologist whom have chosen to ignore follow-up research to their claims, as well as, the basic physical chemistry research which has otherwise been deemed a solid basis for much modern chemistry. I do not understand neither the Christy quote, the skewing of the National Academies' review, or continued presentation of dated meta-research that can actually be countered by the references in Wikipedia. 173.242.89.38 (talk) 05:20, 16 February 2011 (UTC)EAZen, occasionally logged in,

Old general discussion

I've (William M. Connolley 20:03 Feb 12, 2003 (UTC)) moved 2 paras to the end. These are:

the intro that someone copied in, viz:

"The historical temperature record shows the fluctuations of the temperature of the atmosphere and the oceans throughout history. Climate scientists generally agree that Earth has undergone several cycles of global warming and global cooling in the last 20,000 years, with the average air temparature fluctuating within a range of about 3 Celsius degrees (5 Fahrenheit degrees), over this time period."

This is mangled info. Someone can straighten it out if they like. If you look over the last 20 kyr, the biggest signal you see is the end of the last ice age - so the stuff about little cycles is then in the noise.

There are various sub-cycles/sub-signals, of ??1500 year ish?? periodicity; and their are the D-O events etc etc. But the above para mangles that. *Also* it fits rather poorly with the emphasis of this subsection-now-a-page, ie on the last 150 or 1000 years - so it shouldn't be up there in the intro.

I've also pushed

"In January 2002, scientists released data showing that Antarctica had grown about 25% (???). Some editorial writers claimed that this contradicts the expectation that rising temperatures should cause the ice cap to shrink. However, the scientists studying the situation in the Antarctic who released this data point out that local cooling in some areas is consistent with an overall trend of global warming and say that "the ice-sheet growth that we have documented in our study area has absolutely nothing to do with any recent climate trends."[9]"

into the misc section. The first sentence is junk. If its to stay, someone has to find a decent ref to what its supposed to mean. Mind you, ref [9] is nice and its a pity I've misc'd it too...

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The IPCC says that it has corrected the land station data to account for the urban heat island effect. To do: find and summarize their correction technique.

The comment above has been around for about a year, and still no one has shown me where in any IPCC report they have explained how they "account for" urban heat islands. So I'm inclined to say rather:

Critics of the IPCC report note that it fails to explain how it accounts for the urban heat islands. These critics argue that the heat island effect correlates with land-based thermometer readings better than the global warming theory espoused by the IPCC.

... or something along those lines. Work with me here, folks. Let's make an informative and neutral article. --Uncle Ed

That looks fairly reasonable - I'd modify slightly:

The IPCC report does not explain how it accounts for the urban heat island effect - increased warming due to proximity to major cities. The heat island effect, if not properly accounted for, would tend to increase the amount of apparant warming.

Martin

(William M. Connolley 09:46 Feb 13, 2003 (UTC)) There is at least a problem in the wording here. IPCC doesn't do research, it reports other peoples. But apart from that... see section 2.2.2.1 [1]. In particular:

These results confirm the conclusions of Jones et al. (1990) and Easterling et al. (1997) that urban effects on 20th century globally and hemispherically averaged land air temperature time-series do not exceed about 0.05°C over the period 1900 to 1990 (assumed here to represent one standard error in the assessed non-urban trends). However, greater urbanisation influences in future cannot be discounted. Note that changes in borehole temperatures (Section 2.3.2), the recession of the glaciers (Section 2.2.5.4), and changes in marine temperature (Section 2.2.2.2), which are not subject to urbanisation, agree well with the instrumental estimates of surface warming over the last century. Reviews of the homogeneity and construction of current surface air temperature databases appear in Peterson et al. (1998b) and Jones et al. (1999a). The latter shows that global temperature anomalies can be converted into absolute temperature values with only a small extra uncertainty.

Errr... shouldn't all this go into the UHI page?

Yep. And then summarised here. :) It all seems rather a lot of work... :-/ Martin

William, the large quote above (0.05°C over the period 1900 to 1990) seems at first reading to answer Martin's other question: are heat islands causing global warming. My question is different: are temperature readings taken within heat islands giving a false impression of global warming. That is, (1) if a city gets 0.8°C warmer, and this warming is averaged in with all other temperature differences, I think this would be a statistical error. What do you think? Also, (2) if cities get much warmer, suburbs get kind of warmer, rural areas get a bit warmer, and uninhabited areas don't get warmer at all, what would this tell us? (Not saying that's the case for now, just asking what this would tell us if it were so.) --Uncle Ed 17:19 Feb 13, 2003 (UTC)

AFAICT, "globally and hemispherically averaged land air temperature time-series" - I think this phrase is referring to the temperature readings rather than the actual temperatures - IE, it answers your question... Oh, I'm copying some of this stuff to the urban heat island page. Martin

There is an answer to UE from IPCC. Essentially, you can (if you wish) separate out the obviously-likely-to-be-affected stations if you like, but it makes little difference. Reasons include: cities are small areas anyway; the trends from cities (etc) don't in fact differ substantially from the trends without them; in fact the trends over city areas agree quite well with the dreaded MSU... I'll try to find this and add it in, since its clearly a concern (William M. Connolley 21:31 Feb 13, 2003 (UTC)).

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I have started studying a paper on the temperature record in the USSR. The writers find no warming trend in rural stations and hint (or imply) that other researchers have selectively chosen data to fit their "warming" views. [Read it yourself] and decide. --Uncle Ed 17:52 Feb 13, 2003 (UTC)

Its worth reading (William M. Connolley 21:36 Feb 13, 2003 (UTC)). I've had a brief look before. Of the 2 stations I picked to check his analysis, one had the jump he claimed (according to objective statistics) and one didn't, or it was impossible to tell: the trends he claimed as implausible against "neighbouring" stations were from places 100's of km away, and in different exposures: near the sea or not.

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Martin and William,

I'm not sure either of you is getting my point. I am not wondering whether a few hot cities are making the whole world hot.

I am wondering whether a large number of the temperature readings from weather stations in and near rapidly warming cities, when averaged with a relatively small number of temperature readings from rural and remote stations, are giving a false impression of global warming. That is, it might be that (A) the only parts of the world that are warming are the urban heat islands and (B) the only reason these are heating up is because cities absorb and generate heat; rather than (C) that carbon dioxide, etc. is causing worldwide warming.

Do you understand my point? (I'm not asking whether you agree with my point of view, but only whether my English is clear.) --Uncle Ed 22:33 Feb 13, 2003 (UTC)

I believe so - let me paraphrase to try and prove it.

* Because of the urban heat island effect, cities are warming up more than the surrounding countryside

* Thermometers are recording an increase in temperature

* Many thermometers are located near urban heat islands

* Therefore, the temperature increase recorded by thermometers may overestimate the actual temperature increase of the climate as a whole.

To draw a parallel, one shouldn't put the thermostat in one's house next to a log fire, because in that case the thermostat will overestimate the general temperature of one's house.

My reading of the IPCC report is that the distortion introduced by the urban heat island effect is, at most, 0.05°. In other words, if we had located our thermometers away from urban heat islands, they would have recorded 0.05° less temperature increase over the period 1900 to 1990. Of course, this depends on whether you trust the research cited by the IPCC... Martin

I mostly agree with Martin. Have you read the bit about marine and borehole temperatures? This does a lot to counter your point. I also think you're wrong to suppose that, numerically, urban reading predominate. Martin: note that strictly speaking IPCC reprots that UHI leads to at most 0.05 *uncertainty*. They don't (I think) explicitly state that this is necessarily in the warming direction.

Thank you, both, for helping me to feel understood. Now I'll have a G-R-E-A-T weekend! ^_^ (Uncle Ed)

Overcoverage?

Someone (I don't know who) added an "overcoverage" tag to the US section. Now a succession of anons want to remove it ([2] is the latest). It seems plausible to me though William M. Connolley (talk) 17:14, 13 November 2009 (UTC)

Seems fairly obvious to me that the section is overly US-centric. -Atmoz (talk) 22:27, 13 November 2009 (UTC)

I disagree. Just because the information relates to the US observation system doesn't mean that it's over-coverage. Granted, ideally we'd be able to discuss evaluations of other countries' systems (and someone may have good sources on that), but that's not a reason not to cover what we have on the reliability of the US system. We would have a problem if the text misled the reader into believing the sources cited here related to all observation systems, but that doesn't appear to be the case; it seems to do a good job of identifying exactly which system is being discussed.

Here's what I'd suggest. 1) Move the heading down one level so that it's a subheading under "Uncertainties in the temperature record," and 2) remove the tag. Moving the heading down will give less prominence to the topic relative the the article as a whole. It might also make sense to 3) add an "expand" or "globalize" tag to the parent "Uncertainties in the temperature record" section. Ultimately, that seems to me what the article needs - parallel information on other observation systems. EastTN (talk) 15:31, 17 November 2009 (UTC)

User:KimDabelsteinPetersen has stuck the tag back in. I still disagree, because discussing the reliability of the US land system seems a reasonable subtopic under a discussion of uncertainties in the temperature record. What creates a problem is not inclusion of that information, but a lack of parallel information on other systems, and particularly on non-US systems. I would argue that the best way to improve the balance of this discussion is to bring in additional information, rather than exclude the information on the reliability of the US land-based system. EastTN (talk) 21:19, 20 November 2009 (UTC)

No, i did not put the tag back in. I put an entirely different tag on it: Undue-section. The reason for that tag, is that almost the whole section is based upon a minority viewpoint (Pielke Sr.) and a rather substantial amount of synthesis, this has been discussed here before. Strangely enough the mainstream position Peterson is only provided a single sentence. --Kim D. Petersen (talk) 21:37, 20 November 2009 (UTC)

You're right - you did put in the Undue-section tag rather than the Overcoverage tag. In any event, it seems to me that the section does a good job of identifying the studies involved, who did each, and that Peterson and Pielke disagree about the significance of these issues. If you can expand the discussion of Peterson's view, that would be helpful. Ideally, it would seem that the discussion of his rebuttal should be of roughly comparable length and detail as the discussion of the reports he's disagreeing with. Beyond that, if we could find a good secondary source documenting which conclusions regarding these particular technical issues are majority views, which are minority views, and the relative prominence of each in the profession, that would be very helpful. EastTN (talk) 19:31, 22 November 2009 (UTC)

UKMO ref

Add in http://www.metoffice.gov.uk/climatechange/science/explained/explained5.html ? William M. Connolley (talk) 22:04, 5 December 2009 (UTC)

Done. Gabriel Kielland (talk) 12:14, 6 December 2009 (UTC)

What is a "climate observing system"?

E.g. it could be: 1) a network of sensors stations 2) an organization with a network of sensor stations and their own practices and standards 3) a single sensor station. Velle (talk) 01:57, 23 December 2009 (UTC)