RealClimate

Climate science from climate scientists...

You are here: Home / Archives for Climate Science / Climate modelling

Climate modelling

11ºC warming, climate crisis in 10 years?

by

Translations: (Français) (English)

by Gavin Schmidt and Stefan Rahmstorf

Two stories this week, a paper in Nature (Stainforth et al, 2005) describing preliminary results of the climateprediction.net experiments, and the Meeting the Climate Challenge report from a high level political group have lead to dramatic headlines. On the Nature paper, BBC online reported that “temperatures around the world could rise by as much as 11ºC “; on the latter report it headlined: “Climate crisis near ‘in 10 years’”. Does this mean there is new evidence that climate change is more serious than previously thought? We think not.

[Read more…] about 11ºC warming, climate crisis in 10 years?

Global Dimming II

by

Translations: (Français) (English)

Guest commentary on BBC documentary on “Global Dimming” aired on January 13th 2005 by Beate Liepert, LDEO, Columbia University

I haven’t yet seen the documentary. I have only read the transcript and hence was spared the pictures of the potential apocalypse and the invocation of biblical-scale famines. However, as one of the lead scientists on the topic [and who was interviewed by the BBC for the Horizon documentary (transcript, previous post)], I feel I should explain a few things about it without using religious analogies and stoking unnecessary fear.

First though, this is a nice example of the power of words: Gerry Stanhill coined the observed reduction in solar energy reaching the ground “global dimming”. He called it “global” dimming because the technical term for the radiative energy is called “global solar radiation” and it contrasts nicely with the more common “global warming”.

[Read more…] about Global Dimming II

Is Climate Modelling Science?

by

At first glance this seems like a strange question. Isn’t science precisely the quantification of observations into a theory or model and then using that to make predictions? Yes. And are those predictions in different cases then tested against observations again and again to either validate those models or generate ideas for potential improvements? Yes, again. So the fact that climate modelling was recently singled out as being somehow non-scientific seems absurd.
par Gavin Schmidt (traduit par Gilles Delaygue)

A première vue, cela semble une question étrange. Est-ce-que la science n’est pas précisément la quantification d’observations dans une théorie ou un modèle, et ensuite son utilisation pour faire des prédictions ? Oui. Et est-ce-que ces prédictions de différents cas sont ensuite confrontées, maintes fois, aux observations, afin soit de valider ces modèles ou bien de faire émerger des idées d’amélioration ? Oui, encore une fois. Ainsi la mise à l’index récente de la modélisation climatique comme quelque chose de non scientifique semble absurde.

(suite…)

[Read more…] about Is Climate Modelling Science?

Senator Inhofe on Climate Change

by

by Michael Mann, Stefan Rahmstorf, Gavin Schmidt, Eric Steig, and William Connolley

Senator James Inhofe (R) of Oklahoma recently provided us with an update of his views on the issue of climate change in a speech given on the opening senate session, January 4, 2005. His speech opened with the statement:

As I said on the Senate floor on July 28, 2003, “much of the debate over global warming is predicated on fear, rather than science.” I called the threat of catastrophic global warming the “greatest hoax ever perpetrated on the American people,” a statement that, to put it mildly, was not viewed kindly by environmental extremists and their elitist organizations.

Cutting through much of his polemic, Inhofe’s speech contains three lines of scientific argument which, according to him, provide “compelling new scientific evidence” that anthropogenic global warming is not threatening. We here submit his statements to scrutiny.
[Read more…] about Senator Inhofe on Climate Change

Michael Crichton’s State of Confusion II: Return of the Science

by

Our first post on Crichton’s new novel “State of Fear” hits most of the key points, though there are a few more errors in the book that we hope to expand upon in future posts.

But for those of you uninterested in buying and reading the book, you can actually find a similar-minded opinion piece by Crichton criticizing climate science (and everything from SETI and the “Drake Equation” to Carl Sagan in the process) here in the public domain.

[Read more…] about Michael Crichton’s State of Confusion II: Return of the Science

Michael Crichton’s State of Confusion

by

Translations: (Français) (English)

In a departure from normal practice on this site, this post is a commentary on a piece of out-and-out fiction (unlike most of the other posts which deal with a more subtle kind). Michael Crichton’s new novel “State of Fear” is about a self-important NGO hyping the science of the global warming to further the ends of evil eco-terrorists. The inevitable conclusion of the book is that global warming is a non-problem. A lesson for our times maybe? Unfortunately, I think not.

[Read more…] about Michael Crichton’s State of Confusion

The Arctic Climate Impact Assessment III

by

Does the ACIA overstate the problem of ozone depletion? The overview report states that the “stratospheric ozone layer over the Arctic is not expected to improve significantly for at least a few decades”. This is partly because CFC concentrations (that enhance stratospheric ozone destruction) are only expected to decrease slowly as a function of restrictions imposed by the Montreal Protocol and subsequent amendments. Another factor is the fact that stratospheric temperatures are generally cooling as greenhouse gases increase (see MSU Temperature Record, also Why does the stratosphere cool when the troposphere warms?). Due to the temperature dependence on the rates of chemical reactions involving ozone, cooler temperatures also lead to more ozone destruction. Stratospheric temperatures, particularly near the pole are also significantly influenced by dynamical changes, and in particular, the strength of the [Read more…] about The Arctic Climate Impact Assessment III

Temperature Variations in Past Centuries and the so-called "Hockey Stick"

by

Translations: (Français) (English)

Instrumental data describing large-scale surface temperature changes are only available for roughly the past 150 years. Estimates of surface temperature changes further back in time must therefore make use of the few long available instrumental records or historical documents and natural archives or ‘climate proxy’ indicators, such as tree rings, corals, ice cores and lake sediments, and historical documents to reconstruct patterns of past surface temperature change. Due to the paucity of data in the Southern Hemisphere, recent studies have emphasized the reconstruction of Northern Hemisphere (NH) mean, rather than global mean temperatures over roughly the past 1000 years.

[Read more…] about Temperature Variations in Past Centuries and the so-called "Hockey Stick"

Antarctic cooling, global warming?

by

Translations: (Français) (English)

by Eric Steig and Gavin Schmidt
Long term temperature data from the Southern Hemisphere are hard to find, and by the time you get to the Antarctic continent, the data are extremely sparse. Nonetheless, some patterns do emerge from the limited data available. The Antarctic Peninsula, site of the now-defunct Larsen-B ice shelf, has warmed substantially. On the other hand, the few stations on the continent and in the interior appear to have cooled slightly (Doran et al, 2002; GISTEMP). At first glance this seems to contradict the idea of “global” warming, but one needs to be careful before jumping to this conclusion.

[Read more…] about Antarctic cooling, global warming?

Michaels misquotes Hansen

by

Pat Michaels (under the guise of the Greening Earth society) is particularly fond of misquoting Jim Hansen, director of the NASA GISS laboratory (and in the interests of full disclosure, GS’s boss).

Recently he claimed that Dr. Hansen has now come around to the ‘skeptics’ (i.e. Pat Michaels) way of thinking and suggests that they agree on the (small) amount of warming to be expected in the future. Michaels quotes Hansen from a 2001 PNAS paper:

[Read more…] about Michaels misquotes Hansen