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How Red are my Proxies?

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Guest commentary by David Ritson

Realclimate recently gave a detailed review of the issues surrounding the Von Storch et al. (2004) Science article that purported to show that the paleo-reconstructions of Mann et al. were invalid. Part of the review centered on a comment of Wahl, Amman and myself and the response to it by Von Storch et al that appeared on April 27 in Science. The response admitted that our critique of their original results was correct but then opened up a new area of debate. As in their original 2004 article von Storch et al had used a coupled climate model (AOGCM) to simulate the temperatures of the last two thousand years. They had then generated pseudo-proxies by adding noise at selected spatial locations to the AOGCM generated temperature histories. The added noise was purportedly designed to represent non-climatic effects such as disease or insect infestation. This simulated ‘noisy’ world then can be used as a test-bed for the reconstruction methodology. A given analysis procedure is validated if it successfully recovers the original AOGCM noise free results and could be rejected if it fails to recover the original results. Of course such testing only makes sense if the simulated test world has characteristics similar to the real-world. [Read more…] about How Red are my Proxies?

More on the Arctic

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By Michael Mann & Phil Jones (guest)

Svalbard, an Arctic island in the Northern North Atlantic, is predicted to warm considerably more than most of the rest of the earth in many model-based scenarios. See for example the figure to the right, which represents a relatively high-end IPCC Third Assessment Report scenario for the projected surface temperature difference between the period 2071 -2100 and 1961-1990. Svalbard is the island north of Norway at about 80N between 15-30E.

The enhanced warming in this region is related to the issue of polar amplification that we have discussed previously on RC. It also happens that the Svalbard meteorological station is the 2nd station in the World Meteorological Organization (WMO) meteorological station list. This means that it tends to get noticed. The Climatic Research Unit (CRU) of the University of East Anglia maintains one prominent version of the global surface temperature data set and as part of its routine quality control, CRU flags any unusual (anomalous warm or cold) new measurements that come in. Svalbard has now been flagged consistently over the past several months, but the values have been confirmed as accurate by the Norwegian Met Service, which operates the Svalbard station.
[Read more…] about More on the Arctic

Thank you for emitting

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A recent movie, ‘Thank You for Smoking‘, amusingly highlighted the lengths that PR reps for the tobacco companies would go to distort the public discourse on the health effects of smoking. Lest you thought that was of merely historical relevance, we would like to draw your attention to two of the funniest videos around. Lifting a page straight out of the Nick Naylor playbook, the CEI (an industry-funded lobby group) has launched a new ad campaign that is supposed to counteract all those pesky scientific facts about global warming.

The first ad (both available here) deserves to become a classic of the genre. It contains the immortal lines ‘CO2: they call it pollution, we call it Life!’ – it is beyond parody and without content – and so you should definitely see it. The second ad has a little more substance – but is as misleading as you might expect.
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El Niño and Global Warming

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By Rasmus Benestad & Raymond Pierrehumbert

This is the first part of a planned mini-series of 3 posts on tropical climate, circulation, and oceanic response in conjunction with a global warming. Climate change related to a global warming is more than just temperature and precipitation -massive atmospheric circulations change too, and these changes can have consequences.

[Read more…] about El Niño and Global Warming

Current volcanic activity and climate?

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There has been a lot in the news recently about current volcanic activity – Merapi in Indonesia and Bezymianny in the Kamchatka peninsula in Russia, but while most reports have focussed on the very real dangers to the local populace and air traffic, volcanoes can have important impacts on climate as well. However, there are a number of conditions that need to be fulfilled before an eruption will show up in the climate record. [Read more…] about Current volcanic activity and climate?

Al Gore’s movie Le film de Al Gore

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by Eric Steig

Along with various Seattle business and community leaders, city planners and politicians, a large group of scientists from the University of Washington got a chance to preview the new film, An Inconvenient Truth, last week. The film is about Al Gore’s efforts to educate the public about global warming, with the goal of creating the political will necessary for the United States to take the lead in efforts to lower global carbon emissions. It is an inspiring film, and is decidedly non-partisan in its outlook (though there are a few subtle references to the Bush administration’s lack of leadership on this and other environmental issues).

Since Gore is rumored to be a fan of RealClimate, we thought it appropriate to give our first impressions.
par Eric Steig (traduit de l’anglais par Véronique Pagé)
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MY Review of Books

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I’ve finally got round to reading a number of the many climate change-related books that have been published in recent months. These books seem to have caught the public imagination in ways that are different than in the past, and so it’s worth examining how they do. The three I’ve read are; Eugene Linden’s The Winds of Change, Elizabeth Kolbert’s Field Notes from a Catastrophe and Tim Flannery’s The Weather Makers. The first two writers are journalists, while the third is a scientist by background, and while there is some overlap in contents all of them, they are clearly distinct works in quite different styles. I’ll mostly stick to commenting on the science though… [Read more…] about MY Review of Books

IPCC draft: No comment.

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As everyone has now realised, the second-order draft of the new IPCC report has become very widely available and many of the contributors to this site, commenters and readers will have seen copies. Part of the strength of the IPCC process are the multiple stages of review – the report is already significantly improved (in clarity and scientific basis) from the first round of reviews, and one can anticipate further improvements from the ongoing round as well. Thus no statements from this draft report can be considered ‘official’. While most of the contents of the report will come as no surprise to frequent visitors here, we have decided that we are not going to discuss the report until it is finalised and released (sometime in February 2007). At that time, we’ll go chapter by chapter hopefully pulling out the interesting bits, but until then, we feel it’s more appropriate to respect the ‘Do not cite or quote’ injunctions that can be found on every page. We trust that our commenters will likewise respect the process. Patience, people, patience!

A Mistake with Repercussions

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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

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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. [Read more…] about Gray and Muddy Thinking about Global Warming