Friday, December 21, 2007

Has global warming stopped?

In an interesting post in the New Statesman, David Whitehouse raises the question "has global warming stopped?" He notes that:
  • For the past decade the world has not warmed. Global warming has stopped. It's not a viewpoint or a sceptic's inaccuracy. It's an observational fact.
  • ...either the hypothesis of carbon dioxide induced global warming holds but its effects are being modified in what seems to be an improbable though not impossible way, or, and this really is heresy according to some, the working hypothesis does not stand the test of data.
  • It was a pity that the delegates at Bali didn't discuss this or that the recent IPCC Synthesis report did not look in more detail at this recent warming standstill.
The corollary to this situation is that many empirical facts that run counter to the prevailing paradigm of AGW receive scant attention in the mainstream media. For example, at the same time as Whitehouse is posing his question, a major new study has been published that confirms there is no observed linkage between hurricanes and global warming as promoted by AGW advocates: the science contradicts the fear-mongering.
Roger Pielke has returned to the blogosphere and he examines the paradox posed by the lack of media reaction to the hurricane study:
  • is the media biased in its reporting on climate change?
  • what influence does ideology have on media coverage?
  • how does spin influence media coverage of ecomyths?
Pielke quotes the work of Mullainathan and Shleifer and emphasizes the point that spin can exacerbate the influence of one-sided ideology. When the first news outlet that uncovers the story is ideological and later ones are not, the first one sets the tone and later ones reinforce this spin. This can explain why and how inside sources leak information to news outlets: their principal motivation is to control how the story is eventually spun.
Both these posts serve to highlight the fact that despite all assertions to the contrary, the science of climate change is not settled. As Revkin points out:
  • ...there are at least two areas of persistent, and legitimate, scientific debate left
  • First, there is still a lot of uncertainty about the extent and pace of warming from a particular rise in concentrations of greenhouse gases...
  • Second, there is a wider debate over what to do, or not do, about climate change, with peoples' preferences (a carbon tax, a technology push, building dikes or parasols in space) not so much a function of science as values.
Values and not science remain the primary driver of climate change. And because that is so, media, spin and ideology are central determinants of the debate, and not the science.
Ecomyths are not exorcised by reference to additional facts: they are defeated by the practise of common sense and free will overcoming the oppressive influence of dogma and the imposition of ideological conceit.

Follow up:
Since I posted this, Roger Pielke Sr. has posted this exchange prompted by Revkin's post above. His main point is that climate is not warming as predicted nor as suggested by the standard greenhouse gas hypothesis. Carbon dioxide is at best 30% of the positive climate forcing. Moreover:
  • With respect to added CO2, I am becoming convinced that its effect (threat?) is more from alterations in ocean and land biogeochemistry rather than its radiative heating. I am also convinced (and have published on this as well) that the more heterogenous climate forcings (due to aerosols and land use/land cover) have a much greater impact on climate through alterations in atmospheric and ocean circulations than do the well-mixed greenhouse gases.