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Why we bother

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A letter from a reader (reproduced with permission):

Dear RealClimate team:

I have a background in biology and studied at post-grad level in the area of philosophy of science. For the last few years, I have been working on a book about the logic of argument used in debates between creationists and evolutionists.

About a year ago I decided it was time to properly educate myself about climate science. Being perhaps a little too influenced by Harry M Collins’ “The Golem” (and probably too much modern French philosophy!), I was definitely predisposed to see group-think, political and cultural bias in the work of climatologists.

On the whole, though, I tried hard to follow the principles of genuine skepticism, as I understood them.

Obviously, there are plenty of ill-considered opinions to be found either side of any issue, but only the most ignorant person could fail to see the terrible intellectual gulf between the quality of so-called skeptic sites and those defending the science behind the AGW thesis.

What convinced me, though, is that the arguments made by a few sites like yours are explicit and testable. In particular, it is useful that RealClimate sticks to the science as much as possible. It has been a lot of hard work to get here, but I am now at a point where I understand the fundamentals of climate science well enough to articulate them to others.

For my part, I am grateful to you guys. I hope it gives you some small amount of satisfaction to know that your work can convert readers who really were skeptics in the beginning. I use the word ‘skeptic’ carefully – the one thing most commonly absent from the so-called ‘skeptics’ is authentic skepticism.

By the way, my book is an attempt to categorise the various logical errors people fall into when they search for arguments to support a conclusion to which they have arrived at a priori. It will now have a few chapters on global warming.

All the best,

Close Encounters of the Absurd Kind

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Guest commentary from Ben Santer

Part 2 of a series discussing the recent Guardian articles

A recent story by Fred Pearce in the February 9th online edition of the Guardian (“Victory for openness as IPCC climate scientist opens up lab doors”) covers some of the more publicized aspects of the last 14 years of my scientific career. I am glad that Mr. Pearce’s account illuminates some of the non-scientific difficulties I have faced. However, his account also repeats unfounded allegations that I engaged in dubious professional conduct. In a number of instances, Mr Pearce provides links to these allegations, but does not provide a balanced account of the rebuttals to them. Nor does he give links to locations where these rebuttals can be found. I am taking this opportunity to correct Mr. Pearce’s omissions, to reply to the key allegations, and to supply links to more detailed responses.
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Daily Mangle

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Yesterday, the Daily Mail of the UK published a predictably inaccurate article entitled “Climategate U-turn as scientist at centre of row admits: There has been no global warming since 1995”.

The title itself is a distortion of what Jones actually said in an interview with the BBC. What Jones actually said is that, while the globe has nominally warmed since 1995, it is difficult to establish the statistical significance of that warming given the short nature of the time interval (1995-present) involved. The warming trend consequently doesn’t quite achieve statistical significance. But it is extremely difficult to establish a statistically significant trend over a time interval as short as 15 years–a point we have made countless times at RealClimate. It is also worth noting that the CRU record indicates slightly less warming than other global temperature estimates such as the GISS record.

The article also incorrectly equates instrumental surface temperature data that Jones and CRU have assembled to estimate the modern surface temperature trends with paleoclimate data used to estimate temperatures in past centuries, falsely asserting that the former “has been used to produce the ‘hockey stick graph’”.

Finally, the article intentionally distorts comments that Jones made about the so-called “Medieval Warm Period”. Jones stated in his BBC interview that “There is much debate over whether the Medieval Warm Period was global in extent or not. The MWP is most clearly expressed in parts of North America, the North Atlantic and Europe and parts of Asia” and that “For it to be global in extent, the MWP would need to be seen clearly in more records from the tropical regions and the Southern hemisphere. There are very few palaeoclimatic records for these latter two regions.”

These are statements with which we entirely agree, and they are moreover fully consistent with the conclusions of the most recent IPCC report, and the numerous peer-reviewed publications on this issue since. Those conclusions are that recent Northern Hemisphere warming is likely unprecedented in at least a millennium (at least 1300 years, in fact), and that evidence in the Southern Hemisphere is currently too sparse for confident conclusions. Mann et al in fact drew those same conclusions in their most recent work on this problem (PNAS, 2008).

Unfortunately, these kinds of distortions are all too common in the press nowadays and so we must all be prepared to respond to those journalists and editors who confuse the public with such inaccuracies.

Update 2/16/10. Phil Jones has confirmed to us that our interpretations of his comments in the BBC interview are indeed the correct ones, and that he agrees with the statements in our piece above. He and his CRU colleagues have also put up an response to some of the false allegations in a previous piece in the UK Guardian. We’ll report further such developments as they happen.

IPCC errors: facts and spin

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Translations: (Czech) (Svenska) (English)

Currently, a few errors –and supposed errors– in the last IPCC report (“AR4”) are making the media rounds – together with a lot of distortion and professional spin by parties interested in discrediting climate science.  Time for us to sort the wheat from the chaff: which of these putative errors are real, and which not? And what does it all mean, for the IPCC in particular, and for climate science more broadly?

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The IPCC is not infallible (shock!)

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Translations: (Italian) (English)

Like all human endeavours, the IPCC is not perfect. Despite the enormous efforts devoted to producing its reports with the multiple levels of peer review, some errors will sneak through. Most of these will be minor and inconsequential, but sometimes they might be more substantive. As many people are aware (and as John Nieslen-Gammon outlined in a post last month and Rick Piltz goes over today), there is a statement in the second volume of the IPCC (WG2), concerning the rate at which Himalayan glaciers are receding that is not correct and not properly referenced.

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2009 temperatures by Jim Hansen

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Translations: (Français) (English)

This is Hansen et al’s end of year summary for 2009 (with a couple of minor edits). Update: A final version of this text is available here.

If It’s That Warm, How Come It’s So Damned Cold? 

 
by James Hansen, Reto Ruedy, Makiko Sato, and Ken Lo
 
The past year, 2009, tied as the second warmest year in the 130 years of global instrumental temperature records, in the surface temperature analysis of the NASA Goddard Institute for Space Studies (GISS). The Southern Hemisphere set a record as the warmest year for that half of the world. Global mean temperature, as shown in Figure 1a, was 0.57°C (1.0°F) warmer than climatology (the 1951-1980 base period). Southern Hemisphere mean temperature, as shown in Figure 1b, was 0.49°C (0.88°F) warmer than in the period of climatology.


Figure 1. (a) GISS analysis of global surface temperature change. Green vertical bar is estimated 95 percent confidence range (two standard deviations) for annual temperature change. (b) Hemispheric temperature change in GISS analysis. (Base period is 1951-1980. This base period is fixed consistently in GISS temperature analysis papers – see References. Base period 1961-1990 is used for comparison with published HadCRUT analyses in Figures 3 and 4.)

The global record warm year, in the period of near-global instrumental measurements (since the late 1800s), was 2005. Sometimes it is asserted that 1998 was the warmest year. The origin of this confusion is discussed below. There is a high degree of interannual (year‐to‐year) and decadal variability in both global and hemispheric temperatures. Underlying this variability, however, is a long‐term warming trend that has become strong and persistent over the past three decades. The long‐term trends are more apparent when temperature is averaged over several years. The 60‐month (5‐year) and 132 month (11‐year) running mean temperatures are shown in Figure 2 for the globe and the hemispheres. The 5‐year mean is sufficient to reduce the effect of the El Niño – La Niña cycles of tropical climate. The 11‐year mean minimizes the effect of solar variability – the brightness of the sun varies by a measurable amount over the sunspot cycle, which is typically of 10‐12 year duration.

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Lindzen and Choi Unraveled

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Guest Commentary by John Fasullo, Kevin Trenberth and Chris O’Dell

A recent paper by Lindzen and Choi in GRL (2009) (LC09) purported to demonstrate that climate had a strong negative feedback and that climate models are quite wrong in their relationships between changes in surface temperature and corresponding changes in outgoing radiation escaping to space. This publication has been subject to a considerable amount of hype, for instance apparently “[LC09] has absolutely, convincingly, and irrefutably proven the theory of Anthropogenic Global Warming to be completely false.” and “we now know that the effect of CO2 on temperature is small, we know why it is small, and we know that it is having very little effect on the climate”. Not surprisingly, LC09 has also been highly publicized in various contrarian circles.
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Where’s the data?

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Much of the discussion in recent days has been motivated by the idea that climate science is somehow unfairly restricting access to raw data upon which scientific conclusions are based. This is a powerful meme and one that has clear resonance far beyond the people who are actually interested in analysing data themselves. However, many of the people raising this issue are not aware of what and how much data is actually available.

Therefore, we have set up a page of data links to sources of temperature and other climate data, codes to process it, model outputs, model codes, reconstructions, paleo-records, the codes involved in reconstructions etc. We have made a start on this on a new Data Sources page, but if anyone has other links that we’ve missed, note them in the comments and we’ll update accordingly.

The climate science community fully understands how important it is that data sources are made as open and transparent as possible, for research purposes as well as for other interested parties, and is actively working to increase accessibility and usability of the data. We encourage people to investigate the various graphical portals to get a feel for the data and what can be done with it. The providers of these online resources are very interested in getting feedback on any of these sites and so don’t hesitate to contact them if you want to see improvements.

Update: Big thank you to all for all the additional links given below. Keep them coming!

The CRU hack

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As many of you will be aware, a large number of emails from the Climatic Research Unit (CRU) at the University of East Anglia webmail server were hacked recently (Despite some confusion generated by Anthony Watts, this has absolutely nothing to do with the Hadley Centre which is a completely separate institution). As people are also no doubt aware the breaking into of computers and releasing private information is illegal, and regardless of how they were obtained, posting private correspondence without permission is unethical. We therefore aren’t going to post any of the emails here. We were made aware of the existence of this archive last Tuesday morning when the hackers attempted to upload it to RealClimate, and we notified CRU of their possible security breach later that day.

Nonetheless, these emails (a presumably careful selection of (possibly edited?) correspondence dating back to 1996 and as recently as Nov 12) are being widely circulated, and therefore require some comment. Some of them involve people here (and the archive includes the first RealClimate email we ever sent out to colleagues) and include discussions we’ve had with the CRU folk on topics related to the surface temperature record and some paleo-related issues, mainly to ensure that posting were accurate.
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