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Addendum to “A Mistake with Repercussions”

Classé dans: — group @ 27 avril 2006

1. What are “pseudo-proxies” and why are they useful?

Our only information from before the “instrumental period” (the period from which we have systematic measurements with thermometers, starting around 1850) comes from proxy records of climate (like tree rings, ice cores, corals, sediments, pollen etc.). Therefore it is important to know what the available kind and distribution of proxy records can tell us about quantities that we care about (like changes in the average temperature of the northern hemisphere). A typical question is: what accuracy for the northern hemisphere temperature can one expect, given the available number and spatial distribution of proxies? How much uncertainty arises from the non-climatic ‘noise’ in these records? How do the different methods for combining the proxies compare? And so on…

If there was sufficient length of good instrumental data, then we would be able to answer these questions simply by comparing measurements with proxy records. But the instrumental record is short – after all this is the prime reason why we have to rely on proxies.
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A Mistake with Repercussions

Classé dans: — group @ 27 avril 2006

Today, Science published an important comment pointing out that there were serious errors in a climate research article that it published in October 2004. The article concerned (Von Storch et al. 2004) was no ordinary paper: it has gone through a most unusual career. Not only did it make many newspaper headlines [New Research Questions Uniqueness of Recent Warming, Past Climate Change Questioned etc.] when it first appeared, it also was raised in the US Senate as a reason for the US not to join the global climate protection efforts. It furthermore formed a part of the basis for the highly controversial enquiry by a Congressional committee into the work of scientists, which elicited sharp protests last year by the AAAS, the National Academy, the EGU and other organisations. It now turns out that the main results of the paper were simply wrong.
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Gray and Muddy Thinking about Global Warming

Classé dans: — group @ 26 avril 2006

Anybody who has followed press reporting on global warming, and particularly on its effects on hurricanes, has surely encountered various contrarian pronouncements by William Gray, of Colorado State University. A meeting paper that Gray provided in advance of the 2006 27th Conference on Hurricanes and Tropical Meteorology (taking place this week in Monterey California, and covered here by CNN), provides an illuminating window into Gray’s thinking on the subject. Our discussion is not a point-by-point rebuttal of Gray’s claims; there is far more wrong with the paper than we have the patience to detail. Gray will have plenty of opportunities to hear more about the work’s shortcomings if it is ever subjected to the rigors of peer review. Here we will only highlight a few key points which illustrate the fundamental misconceptions on the physics of climate that underlie most of Gray’s pronouncements on climate change and its causes.

Gray’s paper begins with a quote from Senator Inhofe calling global warming a hoax perpetrated on the American people, and ends with a quote by a representive of the Society of Petroleum Geologists stating that Crichton’s State of Fear has "the absolute ring of truth." It is the gaping flaws in the scientific argument sandwiched between these two statements that are our major concern. More »

How not to write a press release

Classé dans: — gavin @ 21 avril 2006

A recent BBC radio documentary on the possible over-selling of climate change, focussed on the link between high profile papers appearing in Nature or Science, the press releases and the subsequent press coverage. One of the examples chosen was the Stainforth et al paper that reported the ranges of climate sensitivity within their super-ensemble of perturbed physics runs. While there was a lot of interesting science in this paper (the new methodology, the range of results etc.) which fully justified its appearance in Nature, we were quite critical of their basic conclusion – that climate sensitivities significantly higher than the standard range (1.5 – 4.5ºC) were plausible – because there is significant other data, predominantly from paleo-climate, that pretty much rule those high numbers out (as we discussed again recently). The press coverage of the paper mostly picked up on the very high end sensitivities (up to 11ºC) and often confused the notion of an equilibirum sensitivity with an actual prediction for 2100 and this lead to some pretty way-out headlines. I think all involved would agree that this was not a big step forward in the public understanding of science.

Why did this happen? Is it because the scientists were being ‘alarmist’, or was it more related to a certain naivety in how public relations and the media work? And more importantly, what can scientists do to help ensure that media coverage is a fair reflection of their work? More »

Kristof on the Apocalypse

Classé dans: — raypierre @ 19 avril 2006

We have noted with pleasure Nicholas Kristof’s column, The Big Burp Theory of the Apocalypse (TimesSelect subscription required), which appeared in the New York Times of 18 April. This column is built around the possibility of a catastrophic methane release from marine clathrate decomposition, but at heart it is really a lament that the more conventional and better understood harms of global warming have not proved sufficient to get the attention of the White House or Congress. This column is a refreshing change from the recent spate of backlash columns by Will, Novak and Lindzen attempting to tar climate scientists with the “a****mist” epithet.

Kristof gives a generous tip of the hat to “the excellent discussion of methane hydrates by scholars at” (Thanks, Nick.) He has clearly made good use of Dave Archer’s RealClimate article on clathrates, and it shows in the Kristof’s sound discussion of the basic science. He is very clear on why a clathrate catastrophe would be a bad thing, but equally clear about the uncertainties. The column even contains an intelligent discussion of the Paleocene-Eocene Thermal Maximum as a possible example of a clathrate catastrophe. taking care to point out that this event might not, in fact, have been caused by methane release. Quite a lot to get in a short column, while still managing to achieve a lively style that surely keeps the readers awake.

Perhaps closest to our hearts is Kristof’s cogently stated theme that uncertainty is in the nature of the science, and is no excuse for inaction — indeed should be a spur to greater action. “The White House has used scientific uncertainty as an excuse for its paralysis. But our leaders are supposed to devise policies to protect us even from threats that are difficult to assess precisely — and climate change should be considered even more menacing than a nuclear-armed Iran.” He concludes, “The best reason for action on global warming remains the basic imperative to safeguard our planet in the face of uncertainty, and our leaders are failing wretchedly in that responsibility.”

Kristof is a 2006 winner of the Pulitzer Prize for commentary. Congratulations, Nick! We hope you keep on reading RealClimate.

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