RealClimate

Climate science from climate scientists...

You are here: Home / Archives for Climate Science

Climate Science

Resolving technical issues in science

by

One of the strengths of science is its capacity to resolve controversies by generally accepted procedures and standards. Many scientific questions (especially more technical ones) are not matters of opinion but have a correct answer.

Scientists document their procedures and findings in the peer-reviewed literature in such a way that they can be double-checked and challenged by others. The proper way to challenge results is, of course, also through the peer-reviewed literature, so that the challenge follows the same standards of documentation as did the original finding.
[Read more…] about Resolving technical issues in science

A biased economic analysis of geoengineering

by

Translations: (Español)

Guest commentary by Alan Robock – Rutgers University

Bjorn Lomborg’s Climate Consensus Center just released an un-refereed report on geoengineering, An Analysis of Climate Engineering as a Response to Global Warming, by J Eric Bickel and Lee Lane. The “consensus” in the title of Lomborg’s center is based on a meeting of 50 economists last year. The problem with allowing economists to decide the proper response of society to global warming is that they base their analysis only on their own quantifications of the costs and benefits of different strategies. In this report, discussed below, they simply omit the costs of many of the potential negative aspects of producing a stratospheric cloud to block out sunlight or cloud brightening, and come to the conclusion that these strategies have a 25-5000 to 1 benefit/cost ratio. That the second author works for the American Enterprise Institute, a lobbying group that has been a leading global warming denier, is not surprising, except that now they are in favor of a solution to a problem they have claimed for years does not exist.

[Read more…] about A biased economic analysis of geoengineering

Still not convincing

by

cloud In a new GRL paper, Svensmark et al., claim that liquid water content in low clouds is reduced after Forbush decreases (FD), and for the most influential FD events, the liquid water content in the oceanic atmosphere can diminish by as much as 7%. In particular, they argue that there is a substantial decline in liquid water clouds, apparently tracking a declining flux of galactic cosmic rays (GCR), reaching a minimum days after the drop in GCR levels. The implication would be that GCR can affect climate through modulating the low-level cloudiness. The analysis is based on various remote sensing products.

[Read more…] about Still not convincing

Friday round-up

by

Two items of interest this week. First, there is an atrocious paper that has just been published in JGR by McLean, de Freitas and Carter that is doing the rounds of the denialosphere. These authors make the completely unsurprising point that that there is a correlation between ENSO indices and global mean temperature – something that has been well known for decades – and then go on to claim that that all trends are explained by this correlation as well. This is somewhat surprising since their method of analysis (which involves taking the first derivative of any changes) eliminates the influence of any trends in the correlation. Tamino has an excellent demonstration of the fatuity of the statements in their hyped press-release and Michael Tobis deconstructs the details. For reference, we showed last year that the long term trends are still basically the same after you account for ENSO. Nevermore let it be said that you can’t get any old rubbish published in a peer-reviewed journal!

Second (and much more interestingly) there is an open call for anyone interested to contribute to setting the agenda for Earth System Science for the next couple of decades at the Visioning Earth Science website of the International Council for Science (ICS). This is one of the umbrella organisations that runs a network of committees and programs that prioritise research directions and international programs and they are looking for ideas. Let them know what your priorities are.

Sea ice minimum forecasts

by

One of the interesting things about being a scientist is seeing how unexpected observations can galvanize the community into looking at a problem in a different way than before. A good example of this is the unexpectedly low Arctic sea ice minimum in 2007 and the near-repeat in 2008. What was unexpected was not the long term decline of summer ice (this has long been a robust prediction), but the size of 2007 and 2008 decreases which were much larger than any model had hinted at. This model-data mismatch raises a number of obvious questions – were the data reliable? are the models missing some key physics? is the comparison being done appropriately? – and some less obvious ones – to what extent is the summer sea ice minimum even predictable? what is the role of pre-conditioning from the previous year vs. the stochastic nature of the weather patterns in any particular summer?

The concentration of polar expertise on the last couple of questions has increased enormously in the last couple of years, and the summer minimum of 2009 will be a good test of some of the ideas that are being discussed. The point is that whether 2009 is or is not a record-setting or near-record setting minimum, the science behind what happens is going to be a lot more interesting than the September headline.

[Read more…] about Sea ice minimum forecasts

Warming, interrupted: Much ado about natural variability

by

A guest commentary by Kyle Swanson – University of Wisconsin-Milwaukee

I am quite humbled by the interest that has been generated by our paper “Has the climate recently shifted?” (Swanson and Tsonis, 2009), and would like the thank the RealClimate editors for the opportunity to give my perspective on this piece.

Before delving into the paper itself, a few words about the place of our work in the global warming “debate” are in order. A quote from the early 20th century Viennese polymath Egon Friedell (which I ran across in the wonderful book Cultural Amnesia by Clive James) captures the situation better than any words I could ever weave;

Electricity and magnetism are those forces of nature by which people who know nothing about electricity and magnetism can explain everything.

Substitute the words “modes of natural climate variability” for “electricity and magnetism,” and well…, hopefully the point is made.
[Read more…] about Warming, interrupted: Much ado about natural variability

Two degrees

by

The countries of the G8 today approved a target of 2° C rise in global average temperature above the natural, preanthropogenic climate, that they resolve should be avoided. The Europeans have been pushing for 2 degrees as a target maximum temperature for several years, but this is something of a development for the Americans. We posted recently on two new papers about what it would take to limit global average warming, finding that it would require fairly strong change in trajectory. About 2° C as a target, we wrote,

… even a “moderate” warming of 2°C stands a strong chance of provoking drought and storm responses that could challenge civilized society, leading potentially to the conflict and suffering that go with failed states and mass migrations. Global warming of 2°C would leave the Earth warmer than it has been in millions of years, a disruption of climate conditions that have been stable for longer than the history of human agriculture. Given the drought that already afflicts Australia, the crumbling of the sea ice in the Arctic, and the increasing storm damage after only 0.8°C of warming so far, a target of 2°C seems almost cavalier.

Nevertheless, we view today’s development as a constructive step.

‘Unscientific America’: A Review

by

Author Chris Mooney (of “Storm World” fame) and fellow “Intersection” blogger, scientist, and writer Sheril Kirshenbaum have written an extraordinary, if rather sobering book entitled ‘Unscientific America’. What I found most refreshing about the book is that it not only isolates the history behind, and source of, the problem in question—the pervasiveness and dangerousness of scientific illiteracy in modern society–but it offers viable solutions. This book is a must read for anybody who cares about science, and the growing disconnect between the scientific and popular cultures (the problem of the so-called “Two Cultures” first discussed by C.P. Snow).

‘Unscientific America’ explores how we’ve come to the point we’re now at, examining the historical factors behind the diminishing prominence of science and scientists in the popular culture of the U.S. since its heyday in the years following WW II. The authors uncover more than enough blame to go around. They find fault with the media, both in how it portrays science and scientists (e.g. the icon of the ‘mad scientist’), and in the decreasing news coverage devoted to issues involving science and technology. They find fault in the way policy makers often abuse science (cherry-picking those particular scientific findings which suit their agenda), and in the behavior of corporate special interests who, in areas such as our own area of ‘climate change’, have often deliberately manufactured false controversy and confusion to dissuade the public from demanding action be taken. At this point, the scientists among you might begin to feel absolved of any responsibility for the problem. Don’t–Mooney and Kirshenbaum won’t allow us to escape blame, and with good reason. As they point out, we ‘eat our own’, when it comes to colleagues engaged in public outreach and science popularization. Case in point: Carl Sagan–a hero to many of us who value science outreach. One of the darker episodes in modern U.S. science history was the blocking by Sagan’s fellow scientists of his entry into the U.S. National Academy of Sciences. Evidently, a majority of his colleagues resented his having become a household name–something they presumably considered unbecoming for a scientist. What sort of message does it send when the most effective science communicator in modern history was shunned by his colleagues for his efforts? Certainly not a good one. This is just one example, and there are many others–it is not surprising that so few scientists to choose to pursue the path of outreach and public education. The reward systems in academia and the scientific world typically do not favor scientists who choose to expend considerable time and effort engaging in public discourse. And here of course, it is as much that system, as the scientists themselves, which is to blame.

[Read more…] about ‘Unscientific America’: A Review

Science at the bleating edge

by

Many of you will remember our pioneering discussion of the Sheep-albedo hypothesis, where we suggested that increasing numbers of sheep would cause a cooling climate because of their impact on the ground reflectivity. Well, new observations have now added significantly more complexity to this seemingly understood situation. It has just been reported that as well as the original sheep-albedo effect, there is now evidence of a second sheep-albedo effect (smaller sheep as the world warms). That would be a amplifying effect in general, but the actual population of sheep concerned come in many colours, so the overall affect is uncertain. (There is even speculation about a third effect (the sheep lifetime albedo impact), which could go either way depending the Lamb Marketing Board advertising campaign).

Yet more evidence that the science is very woolly.

*Title taken from a comment from glen