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Scientists respond to Barton

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by Gavin Schmidt and Stefan Rahmstorf

Many readers will be aware that three scientists (two of which are contributors to this site, Michael Mann and Ray Bradley) have received letters from Representative Joe Barton (Texas), Chairman of the House Energy and Commerce Committee specifically requesting information about their work on the ‘hockey stick’ papers (Mann et al (1998) and Mann et al (1999)) as well as an enormous amount of irrelevant material not connected to these studies.

Many in the scientific community would welcome any genuine interest in climate change from the committee, but the tone and content of these letters have alarmed many scientists and their professional organisations. In the words of Alan Leshner, CEO of the American Association for the Advancement of Science, the Barton letters “give the impression of a search for some basis on which to discredit these particular scientists and findings, rather than a search for understanding.” Other organisations and individual scientists have also expressed strong concerns: [Read more…] about Scientists respond to Barton

The Wall Street Journal vs. The Scientific Consensus El Wall Street Journal sobre el consenso científico en el cambio climático

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We are disappointed that the Wall Street Journal (WSJ) has chosen to yet again distort the science behind human-caused climate change and global warming in their recent editorial “Kyoto By Degrees” (6/21/05) (subscription required).

Last week, the U.S. National Academy of Sciences and 10 other leading world bodies expressed the consensus view that “there is now strong evidence that significant global warming is occurring” and that “It is likely that most of the warming in recent decades can be attributed to human activities”. And just last week, USA Today editorialized that “not only is the science in, it is also overwhelming”.

It is puzzling then that the WSJ editors could claim that “the scientific case….looks weaker all the time”.

While we resist commenting on policy matters (e.g. the relative merits of the Kyoto Protocol or the various bills before the US Senate), we will staunchly defend the science against distortions and misrepresentations, be they intentional or not. In this spirit, we respond here to the scientifically inaccurate or incorrect assertions made in the editorial.

[Read more…] about The Wall Street Journal vs. The Scientific Consensus El Wall Street Journal sobre el consenso científico en el cambio climático

New contributor

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We welcome David Archer of the University of Chicago to the RealClimate team. David adds to our expertise in ocean and carbon cycle modelling and has already contributed a guest post, with more on the way. RealClimate actively solicits contributions from the wider climate science community and so if you’d like to help out, drop us a line.

Betting on climate change

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Guest contribution by James Annan of FRCGC/JAMSTEC.

“The more unpredictable the world, the more we rely on predictions” (Steve Rivkin). The uncertainty of an unknown future imposes costs and risks on us in many areas of life. A cereal-growing farmer risks a big financial loss if the price of grain is low at harvest time, and a livestock farmer may not be able to afford to feed his herd if the price of grain goes up. One way to reduce the risk is to hedge against it in a futures market. The two farmers can enter a forward contract, for one to deliver a set quantity of grain to the other for a fixed price at a future date. And indeed farmers do routinely use futures contracts to reduce their risks.

A translation in Romanian is available here.
A Ukrainian translation is available here.
[Read more…] about Betting on climate change

How much of the recent CO2 increase is due to human activities? L’accroissement du CO2 atmosphérique: sommes nous entièrement responsable?

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Contributed by Corinne Le Quéré, University of East Anglia.

This question keeps coming back, although we know the answer very well: all of the recent CO2 increase in the atmosphere is due to human activities, in spite of the fact that both the oceans and the land biosphere respond to global warming. There is a lot of evidence to support this statement which has been explained in a previous posting here and in a letter in Physics Today . However, the most convincing arguments for scientists (based on isotopes and oxygen decreases in the atmosphere) may be hard to understand for the general public because they require a high level of scientific knowledge. I present simpler evidence of the same statement based on ocean observations, and I explain how we know that not only part of the atmospheric CO2 increase is due to human activities, but all of it.
Corinne Le Quéré, Université d’East Anglia.

C’est une question qui revient sans cesse, bien que nous connaissions déjà la réponse : nous sommes responsable de la totalité de l’accroissement récent du CO2 atmosphérique, et ceci, malgré le fait que les océans et la biosphère terrestre répondent tous deux aux changements de réchauffement global. Les évidences les plus convaincantes pour les scientifiques (basées sur le décroissement de l’oxygène et des isotopes du carbone) ont déja été expliquées dans une page précédente disponible ici et dans une lettre à la revue spécialisée Physics Today. Cependant, ces évidences peuvent être difficiles à saisir pour les non-spécialistes car elles requièrent des connaissances scientifiques importantes. Je présente ici des évidences plus simples qui mènent aux mêmes conclusions et qui expliquent comment on sait que nous sommes responsables non seulement d’une partie de l’accroissement récent du CO2 atmosphérique, mais de la totalité.
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[Read more…] about How much of the recent CO2 increase is due to human activities? L’accroissement du CO2 atmosphérique: sommes nous entièrement responsable?

Global Dimming may have a brighter future Un avenir brillant pour l’assombrissement global ?

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A while ago, we wrote about Global Dimming – a reduction in downward solar radiation of about 4% or about 7W/m2 from 1961 to 1990 was found at stations worldwide. We said at the time that there were hints of a recovery underway post-1990; now research has been published showing this. From Dimming to Brightening: Decadal Changes in Solar Radiation at Earth’s Surface by Martin Wild et al. (Science 6 May 2005; 308: 847-850; subscription required for link) uses surface measurements; Do Satellites Detect Trends in Surface Solar Radiation? by Pinker et al., Science 2005 308: 850-854 uses satellites; both find a recovery of surface downward radiation since about 1990.
Il y a quelques temps, nous écrivions à propos de l’assombrissement global – une réduction de l’irradiation solaire de 4% ou environ 7W/m_ entre 1961 et 1990 observée dans des stations météorologiques autour du monde. Nous disions alors qu’il y avait des indices de reprise en cours après 1990. Des recherches qui le montrent ont maintenant été publiée. De l’assombrissement à l’éclaircissement: changements décennaux de l’irradiation solaire à la surface de la Terre (From Dimming to Brightening: Decadal Changes in Solar Radiation at Earth’s Surface) de Martin Wild et al. (Science 6 Mai 2005; 308: 847-850; abonnement nécessaire pour lire l’article) utilise des mesures faites en surface; Les satellittes détectent-ils des tendances dans l’irradiation solaire ai niveau de la surface? (Do Satellites Detect Trends in Surface Solar Radiation?) de Pinker et al., Science 2005 308: 850-854, utilise des satellites. Les deux études identifient une reprise de l’irradiation solaire de la surface depuis environ 1990.

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[Read more…] about Global Dimming may have a brighter future Un avenir brillant pour l’assombrissement global ?

2005 Record Arctic Ozone Loss

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You read it here first!


Update (09/05/05): Markus Rex was kind enough to send us the full figure from which Nature made their thumbnail, and which is a little clearer. He also cautions that the 2005 numbers are still preliminary, however there is a clear trend towards increasing potential for Arctic ozone loss, which is realised or not depending on the vagaries of each individual winter.

Technical problem apology

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Due to some odd behaviour with our blog software, many people have had problems this week posting comments. We would like to apologise to our readers if they encountered these problems (bizarre redirections and WordPress login screens appearing where they shouldn’t).

We appear to have fixed the problem (fix from here for those interested), but please let us know if anything weird or unusual continues to occur. Thanks for your patience.

Normal service will resume after the break.

Pollution-Climate Connections Liens entre Pollution et Climat

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Guest commentary by Loretta Mickley, Harvard University

Every summer over much of the United States, we brace ourselves for heat waves. During these periods, the air turns muggy and usually smoggy. After a few days, a cold front moves in, sweeping away the pollution and ending the heat. Given that we are on a path towards global warming, atmospheric chemists are asking how climate change could affect air quality. Will warmer temperatures mean more pollution during these episodes? Will episodes last longer? Most importantly, what effect will changes in air quality have on human health?
Article invité par Loretta Mickley, Harvard University (Traduit par Pierre Allemand)

Tous les étés, dans la plupart des régions des USA, nous nous préparons aux vagues de chaleur. Pendant ces périodes, l’air devient très humide et généralement brumeux. Après quelques jours, un front froid survient, balayant la pollution et mettant fin à la chaleur. Etant donné que nous nous acheminons vers un réchauffement global, les spécialistes de la chimie de l’atmosphère se demandent de quelle façon le changement climatique pourrait affecter la qualité de l’air. Des températures plus élevées signifieront-elles plus de pollution durant ces épisodes ? Ces épisodes dureront-ils plus longtemps ? Plus important : quels sont les effets des changements dans la qualité de l’air sur la santé humaine ?
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[Read more…] about Pollution-Climate Connections Liens entre Pollution et Climat