Final nail on warming

Australia’s ABC screened British Channel 4’s The Great Global Warming Swindle. The ABC has a duty to be even-handed in airing controversial issues. Nevertheless, it’s broadcasting of such a program can be questioned. The essential argument of the The Great Global Warming Swindle is that

New evidence shows that that as the radiation coming from the sun varies (and sun-spot activity is one way of monitoring this) the earth seems to heat up or cool down. Solar activity very precisely matches the plot of temperature change over the last 100 years. It correlates well with the anomalous post-war temperature dip, when global carbon dioxide levels were rising. In fact, what is known of solar activity over the last several hundred years correlates very well with temperature. This is what some scientists are beginning to believe causes climate change.

Meanwhile, while we hesitate, the problem worsens.

Bob Brown, leader of the Australian Greens, "found the narrative of Swindle to be compelling and half its conclusion acceptable, for it agreed the Earth is indeed warming. “But I disagree with its denial of any human responsibility or need to change direction. That was the false and dangerous message from Swindle.” Brown criticised the show’s producer, Martin Durkin, as a "charlatan". Nevertheless congratulated the ABC for showing it: "The ABC should be congratulated for screening this contentious documentary. If nothing else, it helps explain how a clever politician such as John Howard rationalised climate change for so long and got it so wrong: the sun can be used to excuse inaction rather than hasten a cure for the self-inflicted disease of climate change now menacing society." "I back the ABC’s decision to screen The Great Global Warming Swindle. We are a free and open democracy, and climate change calls for such a big change in human policy and direction that it must be tested in the best fire the naysayers can hurl at it. Besides, one of the ABC’s most important roles is to provide an outlet for programs that come from minority advocates or that are of interest to a minority of viewers. And there is little doubt only a diminishing minority of Australians will subscribe to the conclusions drawn in Swindle."

By all accounts (well, one anyway) the on-air debate after the broadcast was ludicrous.

Following the screening of the 50-minute film about climate change, a strangely one-sided interview was aired between regular Lateline host Tony Jones and the film’s director, Martin Durkin. The fierce interrogation appeared to leave the filmmaker bemused. A discussion between a panel of eight experts then dissected the documentary, which claimed the chief cause of climate change was not human activity but changes in solar radiation. But it was not long before the 100-strong studio audience became impatient and started calling out questions.

Jones eventually opened the discussion up to the floor, but by the look on his face he quickly realised he should have stuck with the panel. The first question was more a rant about "coal 14", and its dangers—a topic none of the panel seemed to know anything about. Another audience member then asked about Prince Philip’s role in founding the green movement, and how he had once remarked how he wished he could be reincarnated as the ebola virus in order to reduce the population. What did the panel think about that?

Some in the audience began giggling as questions were being asked, which was perhaps a shame because some words of widsom did emerge. The last question came from a man who said he cared less about fighting within the science community than about the government policies needed to address climate change. "Rome is burning, and we are fiddling around here." And with that, the studio lights were turned off.

David Adam, Guardian environment correspondent, says (11 Jul 07) that there is more than enough evidence to dismiss any suggestion that global warning results from changes in the sun’s activity.

Find another culprit

So it’s official, the sun has nothing to do with recent global warming. Scientists have shown that changes in solar activity have nothing to do with the surge in global temperatures measured since the 1970s. Which is a problem for the climate change sceptics, who need something other than human emissions of greenhouse gases to blame it on. The study has been called the final nail in their coffin.

But what’s really new here? The solar link to recent climate change has already been thoroughly examined and dismissed. Researchers already knew that changes in the amount of energy arriving from the sun couldn’t be responsible. And the trend in cosmic rays-the darling "new" theory of the sceptics-is known to go in the wrong direction. Scientifically, this new paper does nothing new except correct some technical errors in a satellite record of solar irradiance-hardly headline stuff. And while recycling old claims as new may be routine for politicians and the media, it is much less common for scientific journals. The top journal Nature decided not to accept this new study for this reason. And the decision by the Royal Society to publish it appears to be as much about politics as science.

Britain’s scientific elite were shaken by the public reaction to Channel 4’s Great Global Warming Swindle. They thought they had won the argument on the causes of climate change. Several who give public lectures on the subject had even started to leave out that section. Mike Lockwood, the physicist behind the new study, admits he wrote the paper as a direct challenge to the programme’s claims. The Royal Society appears to have published it for the same reason.

. . . The new study may yet have a positive effect. It leaves little doubt (again) that human emissions are the culprit, and stamps on another of the snakes released by Channel 4’s swindle. But does science really need the right presentation for it to be authoritative? And how many final nails does a coffin need before it can be buried?

The study published by the Royal Society concludes

There are many interesting palaeoclimate studies that suggest that solar variability had an influence on pre-industrial climate. There are also some detection-attribution studies using global climate models that suggest there was a detectable influence of solar variability in the first half of the twentieth century and that the solar radiative forcing variations were amplified by some mechanism that is, as yet, unknown. However, these findings are not relevant to any debates about modern climate change. Our results show that the observed rapid rise in global mean temperatures seen after 1985 cannot be ascribed to solar variability, whichever of the mechanisms is invoked and no matter how much the solar variation is amplified.
— Mike Lockwood & Claus Fröhlich. Recent oppositely directed trends in solar climate forcings and the global mean surface air temperature. Proceedings of the Royal Society A. 10 July 2007.