Archive by date | June 2007

Atmospheric aerosols: correlation is not causation

Posted by Olive Heffernan on behalf of Kevin E. Trenberth Aerosols in the atmosphere have been hot topics in several recent climate studies but one wonders if the pollution has made not only the atmosphere murkier but also the scientific reasoning? In March a widely reported study in PNAS by Zhang et al. linked changes in storm tracks over the North Pacific to Asian pollution. In this case effects on radiative forcing by atmospheric aerosols supposedly increased deep convective clouds over the Pacific Ocean in winter, a finding based on long-term satellite cloud measurements (1984–2005). The blame was assigned to  … Read more

The presidential race 2008: where the candidates stand

Posted by Olive Heffernan on behalf of Alex Witze There are only 17 months left until the US presidential election, which means it’s time for the jockeying to begin in earnest. On climate issues, this means that the leading candidates from both parties have in recent weeks been competing to see who can be greener than thou. Most notable has been the recent about-face pulled by Illinois senator Barack Obama, the fledgling star of the Democratic party, on coal-to-liquids technology. Illinois is a state with a lot of coal, and so it was perhaps not surprising when earlier this year  … Read more

Rational thought at risk – not freedom

Posted by Olive Heffernan While I usually find the FT an excellent source of comment and discussion on climate change, I was somewhat bemused by last week’s Comment from the President of the Czech Republic, Vaclav Klaus, who writes that “global warming hysteria has become a prime example of the truth versus propaganda problem” and urges society to “resist the politicisation of science and oppose the term ‘scientific consensus’, which is always achieved only by a loud minority, never by a silent majority”. Though clearly no climate expert, Klaus feels sufficiently component to write on the topic of global warming  … Read more

Climate change and media, science and policy: is time on our side?

Posted by Olive Heffernan on behalf of Maxwell T. Boykoff The climate talks at the G8 summit (see Olive Heffernan’s post on the G8 climate talks) have spurred a recent increase in media attention. At the center of this coverage is discussion of cuts in greenhouse gas emissions. Over the past week, proposals ranged from binding emissions cuts across all G8+5 countries by mid-century to ‘aspirational goals’ of cuts, decided on a country-by-country basis through talks over the next two years. As these rival ‘visions’ of international policy action to combat anthropogenic climate change have been negotiated, the June 7  … Read more

More on geoengineering

Further to the post and subsequent discussion on Sunshades, which grew out of this article on geoengineering, I thought I’d point to the new paper by Damon Matthews and Ken Caldeira in PNAS (Proc. Natl. Acad. Sci. USA, 10.1073/pnas.0700419104). It’s an interesting paper that has some fascinating insights into the links between climate and the carbon cycle, and I think contains some pretty bad news for would-be geoengineers.  Read more

Predictions of climate

Posted by Oliver Morton on behalf of Kevin E. Trenberth

I have often seen references to predictions of future climate by the Intergovernmental Panel on Climate Change (IPCC), presumably through the IPCC assessments (the various chapters in the recently completedWorking Group I Fourth Assessment report ican be accessed through this listing). In fact, since the last report it is also often stated that the science is settled or done and now is the time for action.

In fact there are no predictions by IPCC at all. And there never have been. The IPCC instead proffers “what if” projections of future climate that correspond to certain emissions scenarios. There are a number of assumptions that go into these emissions scenarios. They are intended to cover a range of possible self consistent “story lines” that then provide decision makers with information about which paths might be more desirable. But they do not consider many things like the recovery of the ozone layer, for instance, or observed trends in forcing agents. There is no estimate, even probabilistically, as to the likelihood of any emissions scenario and no best guess.

No more to top? Go for the opposite

Posted by Olive Heffernan on behalf of Gian-Reto Walther

Wasn’t it surprising how the media communicated the findings of the latest IPCC reports? Who would have expected that each of the three reports would produce front-page stories and dominate the public discussion for a considerable while. Whereas for previous issues of IPCC reports, the focus of the reporting media was usually set on the remaining uncertainties of the IPCC statements, this time the (still remaining, though smaller) uncertainties were virtually ignored.

In contrast, a competition among media reports was launched exacerbating the consequences of climate change, one overbidding the other. The logical consequence of this is that sooner or later we end up at a point which cannot be topped. Where to go from there?