Climate change agnosticism, John Howard and some inconvenient truths

John Howard, who argued for an emissions trading scheme if the Coalition won the 2007 election, says he is 'agnostic' about climate change. That being so one must wonder why he intended to put a price on carbon all those years ago, when Australia appeared to be falling behind the rest of the western world in seeking to reduce polluting emissions. It was, he implied in London last week in a speech to the Global Warming Policy Foundation, only political, a reaction to the fashion of the time. Clearly he didn't really believe in it. But in the speech he said some more worrying things as well.

Despite its name the Foundation (like its guest) is sceptical about climate change. Howard made several interesting comments, and according to the Sydney Morning Herald (6 November) he claimed before his speech that he has read only one book about climate change. That was written not by a scientist but by a commentator who is a sceptic.

In the speech itself he referred to many people who think climate change is potentially disastrous as having a "sanctimonious tone" in their utterances, said that the advice of the Intergovernmental Panel on Climate Change included "nakedly political agendas", suggested that politicians are faced with attempts to "intimidate" them by insisting they accept the science of climate change, and cautioned that they should not be "browbeaten" into surrendering their job of developing economic policy. There are "plenty of people around", he was quoted as saying, "who want access to public money in the name of saving the planet."

That is quite a list of concerns. Some of what Howard said was contemptuous of science and scientists. Saving the planet, if could credibly be in trouble, is no bad objective. But we can certainly tell where Howard sits on the issue of potential future climate change. He is much more sceptical than agnostic.

Howard also noted that there was a big bush fire in Victoria 163 years ago, before there was any concern about global warming: this comment was in response to claims that climate change is linked to bush fire occurrence. And he told his audience that he feels "instinctively" that claims about the potential future impacts of warming are exaggerated.

There is much here that needs response. Firstly, nobody denies that there have been big bush fires in Australia in the distant past. What Howard says on this is simply a furphy. No link between individual bush fire events and climate change can be made, and scientists routinely caution that it is unwise to consider particular fires to have been the 'result' of warming. But it is entirely logical to suggest that increasing temperatures encourage vegetation to dry out which in turn could make it more likely, once ignition has occurred, for fire to spread more aggressively. Higher temperatures might well be leading to fires that are both more severe and more frequent.

So far, the link has not been made from the bush fire record in Australia. But these are early days, and it is entirely possible that in future the links between climate change and bush fire characteristics will become clearer.

Here it must be said that there is no doubt that global average temperatures have risen, by 0.8 degrees Celsius, since the 1880s. As it happens this represents a very rapid rate of increase over a small number of decades by comparison with earlier known temperature rises established by scientists. These are attested to by a variety of kinds of indirect evidence well back in time.

Moreover the rise has occurred despite 'pauses' or muted increases of the kind that occurred for 30 years from the mid-1940s and from the second half of the 1990s. The first of these pauses was followed by very rapid increases in temperatures. If the established long-term trend is continued into the future ─ and this is the key to the question of whether global warming will be seriously problematic ─ the link between warming and bush fire frequency and intensity is likely to become clearer.

One problem here is that we may not know for decades whether temperature increases have been sufficient to have dangerous consequences. If they have, dealing with the problem will be more difficult than it currently is, especially if the rises become self-sustaining and 'runaway' temperature increases occur as some scientists fear.

For people of Howard's generation this scenario will not have to be faced, but if it occurs it may have severe impacts during the lifetimes of some people who are now with us. They should be given some consideration here, as should the planet.

Given that atmospheric carbon dioxide concentrations have increased rapidly in a proportional sense since the Industrial Revolution, and with good theoretical reasons to believe that there will be a lag between this build-up and a rise in temperature, it is probable that we have already created the conditions for further temperature increases over coming decades. The momentum may already exist for a continuation of what we have seen to date.