Who'd've Discredited It?

'Case against climate change discredited by study' shrieked the Independent yesterday. That must be one hell of a study. Except that it isn't:

A difference in the way British and American ships measured the temperature of the ocean during the 1940s may explain why the world appeared to undergo a period of sudden cooling immediately after the Second World War.

Scientists believe they can now explain an anomaly in the global temperature record for the twentieth century, which has been used by climate change sceptics to undermine the link between rising temperatures and increases in atmospheric carbon dioxide.

Not only does the study (published this week in Nature) not claim to discredit what the Independent's headline claims it discredits, but it doesn't even discredit what the scientists behind the study claim it discredits. Moreover, what the scientists claim their work does discredit was, according to prominent Environmentalists, discredited years ago. And finally, what everybody seems to be trying to discredit isn't even something that sceptics seem to be crediting in the first place.

Yes, sceptics are concerned about the post-war temperature slump, but not because of the sudden steep drop around 1945; it is the downward trend in temperatures between about 1945 and 1975 that they suggest needs explaining (which is actually longer than the upward trend between 1975 and 1998, just so you know), given that greenhouse gas emissions were rising throughout that period.

And as the graph used by the Independent to bolster its case (supplied by CRU, apparently) demonstrates, the Nature study does absolutely nothing to address that concern:



In fact, the most striking thing about the graph is that, once the sampling errors identified by the study have been taken into account, the period of warming in the latter half of the twentieth century was shorter than previously thought, and that the '45-'75 temperature slump is more pronounced.

According to Phil Jones, a co-author of the paper, the study

lends support to the idea that a period of global cooling occurred later during the mid-twentieth century as a result of sulphate aerosols being released during the 1950s with the rise of industrial output. These sulphates tended to cut sunlight, counteracting global warming caused by rising carbon dioxide.

"This finding supports the sulphates argument, because it was bit hard to explain how they could cause the period of cooling from 1945, when industrial production was still relatively low," Professor Jones said.

That might be so. But the aerosols issue is supposed to have been done and dusted long ago. One of the central criticisms aimed at the infamous Great Global Warming Swindle, for example, is precisely that it failed to entertain the idea that the post-1940 decline in global temperatures was the result of increases in sulphurous emissions that masked the forcing effect of rising atmospheric CO2. George Monbiot described the omission as 'straightforward scientific dishonesty'. After all, he said, that 'temperatures declined after the Second World War as a result of sulphate pollution from heavy industry, causing global dimming...is well-known to all climate scientists.' And as we have reported before, this was also one of the main points raised by the Royal Society's Bob Ward and 36 scientific experts in their open letter to Swindle producer Martin Durkin.

And yet, as we've reported elsewhere, other experts in the field just don't agree. UC San Diego atmospheric physicist Veerabhadran Ramanathan, for example, told us that the empirical evidence for the sulphate masking of warming is 'pretty flimsy'. We do not doubt that the Nature study is an important contribution to the field. (Although it's interesting that Steve McIntyre seems to have produced a similar analysis more than a year ago.) What we do doubt is that the headlines, soundbites, and wild interpretations from newspapers and scientists alike bear much relevance to what is a dry, technical, scientific study, which, while increasing our ability to understand and predict climate trends, says little in itself about the truth or otherwise of global warming.

That said, the BBC's Richard Black has demonstrated uncharacteristic reserve in his coverage of the paper, which includes the following quote from CRU's Mike Hulme:

Corrections for this measurement switch have not yet been applied to produce a new graph of 20th Century temperatures - that work is ongoing at the UK Met Office - but as the land temperature record shows a flattening of the upwards trend from the 1940s to the 1970s, clearly something did change around the 1940s to ameliorate the warming.

"It perhaps suggests that the role of sulphate aerosols, that cooling effect, was less powerful than we thought," said Mike Hulme from the University of East Anglia (UEA), who was not involved in the study.

George Monbiot and the Royal Society are just plain wrong - the science is plainly not 'settled'. And so is Steve Connor, the author of the Independent article. As he wrote last year in response to the Swindle:

The programme failed to point out that scientists had now explained the period of "global cooling" between 1940 and 1970. It was caused by industrial emissions of sulphate pollutants, which tend to reflect sunlight. Subsequent clean-air laws have cleared up some of this pollution, revealing the true scale of global warming - a point that the film failed to mention.

'Scientists' have 'explained' nothing of the sort. As this case shows, the science is not settled. Indeed science is never settled. It is constantly re-evaluating what it understands about absolutely everything. And that's especially crucial to bear in mind when the science in question has been bestowed with the kind of political significance that climate science has. To claim otherwise is to do a disservice to both science and politics. It reduces science to a flimsy fig leaf used simply to hide the embarrassing inadequacies of the latest political fad; and it reduces politics to an aimless exercise in number-crunching.

Fat People are Killing the Butterflies

Steve Connor, science editor at the Independent newspaper warns us that

Tropical insects rather than polar bears could be among the first species to become extinct as a result of global warming, a study has found.

What does that even mean? Are the polar bears OK after all? Is the environmental movement looking for a new mascot for climate change? Is it out with the charismatic mega-fauna because of the environmental ethic that 'small is beautiful'? But it's nothing compared to the headline it appears under:

Insects 'will be climate change's first victims'

An image of a butterfly follows, with the caption...

Many tropical insect species, including butterflies, can only tolerate a narrow range of temperatures, and an average rise of 1C to 2C could be disastrous

Contrast with the measured language of the Proceedings of the National Academy of Sciences article on which Connor reports, and which the journal has kindly made available for free:

Our analyses imply that, in the absence of ameliorating factors such as migration and adaptation, the greatest extinction risks from global warming may be in the tropics, where biological diversity is also greatest.

This is not the first time the Independent has gone on about butterflies as the harbinger of doom. Back in March - a particularly cold March, as it happens - Environment Editor Michael McCarthy hit us with:

Last month, [climate change] produced its most remarkable image yet – a photograph, taken in Dorset, of a red admiral, an archetypal British summer butterfly, feeding on a snowdrop, an archetypal British winter flower.

But as we pointed out, the red admiral is far tougher that McCarthy gives it credit for, occasionally making an appearance in Winter, and is certainly not unusual in Spring and Autumn. Yet again, the Independent is making claims about the vulnerability of species that aren't consistent with the state of knowledge.

The BBC is no more level-headed about the research...

The scientists predicted such species would struggle to cope with the 5.4C rise in tropical temperatures expected by 2100.

5.4C expected by whom? Well, expected by the anonymous author of the BBC article, apparently. Certainly, the IPCC makes no specific prediction for temperature rise this century. And 5.4ºC is not mentioned in the PNAS study, nor in the accompanying press release. The only match we can find is in IPCC AR4 where it is the top-end prediction for SRES scenario A2 (Table SPM.3), the range of which is 2.0-5.4ºC. But why pick 5.4ºC? If you're just looking for a big number to scare people with, then why not plump for the upper value for the A1 scenario (1.4-6.4°C)? Is this like buying the second cheapest bottle of wine in a restaurant to prove you are not a skinflint? Or like Josef Fritzl wondering why everyone hates him when he could have been so much more horrible? [EDIT: The BBC has now "corrected" this error.]

Call us pedantic if you like; but imagine the outcry had the BBC reported that global temperatures are expected to rise by only 1.4ºC by the end of the century (the second lowest low point among the four AR4 SRES scenarios). But then, of course, it's not just journalists (and activists) who are happy to over-egg the ecopocalyptic pudding. When, for example, Bob May (erstwhile President of the Royal Society and former chief scientific advisor to the UK government) confidently asserted in the popular media that a global temperature of 2ºC will put 15-40% of all species at risk of extinction, it was on the basis of a single, worst-case study. He was no less unobjective when he announced that climate swindler du jour Martin Durkin was also some sort of whacko HIV/AIDS denialist. And then there are the science academies, who, while being suspicious of the industry move towards open access publishing, are happy to make papers of the the-world-is-screwed-and-we're-all-going-to-die variety available to all and sundry for free. Which is what the US's National Academy of Sciences have done with this paper. And last year the Royal Society did it, too, when they published a paper which they claimed proved once and for all that the sun has absolutely nothing whatsoever to do with global warming. This wasn't just any old paper; it was, in the words of the Royal Society itself, "the truth about global warming". And for some strange reason, we are still expected to take these academies' opinions on what we should do about climate change as the last word on truth and beauty - "respect the facts" as Bob May puts it.

Newspaper editors and headline writers could - possibly - be forgiven for not understanding quite how science works. It's harder to see how science correspondents could. And it's laughable that the science academies seem not to. Funnier is that scientists and science academies are only too happy to criticise journalists, newspapers and TV producers when they report the science 'wrongly' (and you can bet your house that none of them will be criticising the Independent or the BBC on this occasion). But what do they expect? What sort of example do they think are they setting?

As we keep saying, this is no conspiracy. It's just that - as they've been trying to tell us for years - scientists are human, too. Being human and everything, scientists are as jittery about the future and unsure of their role in society as the rest of us. But just because it turns out that they are as anxious as the rest of the world, it doesn't mean that there's any reason to take the claims of environmentalists at face value, or any less reason to maintain objectivity. Just as global warming is convenient for local governments, directionless leaders and crisis politics, it is also convenient for scientists and science academies lacking raison d'être.

Science might never have been quite the objective producer of facts that we like to think it is. But that doesn't mean it shouldn't strive to be an objective seeker of facts. Because striving to be objective about the facts of the material universe is precisely what science is supposed to do. When it applies itself instead to arming political narratives with legitimacy and authority, it talks itself out of a job.