A cool look at Professor Aitkin’s global warming scepticism

He fails to mention clear evidence of the acceleration of both melting and ice movement in Greenland. There is also clear geological evidence for polar melting and sea level rise accompanying higher temperatures.

Three million years ago, when the Earth was 2-3C hotter, sea levels were 15-35m higher. This is roughly consistent with evidence from the last glacial maximum and from a warm period 40 million years ago that about 20m of sea level change occurs for each degree of temperature change.

We are likely to experience at least 2C of warming. The complete melting of the Greenland and West Antarctic ice sheets would contribute about 7m each to sea level, so evidently even more ice was lost three million years ago under not dissimilar conditions. Professor Aitkin’s discussion of potential sea level rise is quite deficient.

Professor Aitkin queries computer climate models at some length. They are indeed still significantly limited, and their results must be treated with care. However our conclusions about global warming do not rest solely on computer models, as the preceding discussion will have made clear.

Professor Aitkin reveals his superficial understanding by claiming that if they can’t make a reliable 24-hour forecast then one shouldn’t believe long-term climate forecasts. He evidently lacks the elementary understanding that weather causes erratic fluctuations around a relatively slowly changing mean, and that climate is about the long-term means.

He also suggests their climate forecasts would be more believable if they would forecast the climate for 2009. However climate scientists repeatedly emphasise that one can’t reach conclusions about global warming from a single year’s record, nor even from trends over a few years, one has to look at longer-term trends.

Having failed to appreciate some of the key arguments supporting the global warming hypothesis, Professor Aitkin turns his attention to explaining to himself why climate scientists persist in making urgent pleas to curb greenhouse gas emissions.

He suggests they are protecting their turf, reputations and pet idea, and revelling in the extra funding and influence they are receiving. He describes the more activist scientists, and environmentalists in general, as holding a “quasi-religious” view. He says The Greens, “greens” and environmentalists welcome and propagate the global warming view because it fits their own perceptions (implying that those people have no rational basis for their views). He says even democratic governments like to have issues to scare people with. (Well yes, we’ve certainly seen the terrorism threat used that way, but I struggle to think of a government that has yet turned to global warming to scare its citizens, as all of them have had to be dragged kicking and screaming to acknowledge the problem.) He says people have an appetite for horror stories, and the media love to play to that (no argument there, but the media don’t care which story they peddle).

There are quite a few things one could say about these characterisations, only a couple of which will be noted here. Sceptics love to claim climate scientists are only in it for the research funding, ego tripping, alleged influence and so on, but they rarely mention the trillions of dollars and dominating global influence that fossil fuel industries have at stake, and that ExxonMobil, in particular, actively protects. Professor Aitkin laments that he has been called a “denialist” by others, yet he labels climate scientists as quasi-religious and with the several other descriptions just mentioned.

Scientists are human, and scientific debates fall short of the ideal. There is turf protection and self-promotion, and rancour are not uncommon. As an advocate of a minority view in my own field for 20 years, a view ultimately vindicated, I am personally acquainted with these imperfections. The IPCC process is specifically intended to step back from the front-line disputes to see what scientists can agree on. This is the part of the IPCC process that seems to have completely escaped Professor Aitkin’s understanding.

Even so, not everybody ends up satisfied with its assessments. Many, me included, feel it is too conservative. However in reaching for the conspiracy theory favoured by sceptics and denialists, to make up for his own deficient understanding, Professor Aitkin besmirches a great many excellent and conscientious scientists.

Professor Aitkin makes belated acknowledgement in his speech of the precautionary principle, which is basically that we would be wise take some preventative action as insurance against potential catastrophe.