Climate change is one of the biggest issues of our time, up there with terrorism and way ahead of the GFC. The debate about it has become politicised – inevitably so, because if the theory is correct we have to either make big changes to our economies or deal with potentially catastrophic environmental changes within the next few decades – but we risk making the wrong call if the politics obscures the science.

Morgan and McCrystal set out to separate the facts from the rhetoric for the benefit of those who, like themselves, cannot follow the science without expert help. It is a reasonable plan and they carry it out methodically, calling on experts from both sides of the debate ('Alarmists' and 'Sceptics') for assistance.

They begin, logically enough, by defining their topic: 'In the simplest possible terms, the theory of anthropogenic global warming states that human activity is enhancing the natural tendency of the atmosphere to trap heat ordinarily radiated from the Earth's surface into space.'

They find a surprising amount of common ground between the two sides. First, climate has varied widely in the past and nature has driven those changes without any help from us. 'Not that you can take much comfort from either fact, however,' as they note, '[since] very few of the climates that have prevailed on Earth in the remote past would support the ecosystems that we know, love and depend on.'

Further, there is general agreement that the Earth has been warming over the last 150 years (although there is disagreement over the causes), that the amount of CO2 in the atmosphere is rising, and that climate and CO2 are linked. Finally, all agree that 'global warming would be a Bad Thing.' Its consequences, if unchecked, would include disruptions of normal weather patterns (result: farm failures, wildlife extinctions and more), loss of the Himalayan glaciers which supply the major rivers of China and the Indian sub-continent (result: famine), and rising sea levels (result: massive flooding, destroying coastal cities and displacing many millions of people).

Arguments about whether or not global warming is driven by natural processes or human activity get one chapter each. The Alarmists show 'ways in which the rate, scale and pattern the warming the Earth is presently experiencing are unlike other warm spells that have been reconstructed from records of the paleoclimate.' They also present good evidence that the 'increases in atmospheric carbon dioxide are due to the combustion of fossil fuel.' Case closed, one would think, especially as the Sceptics come up with '[only] a handful of weak objections to the theory of anthropogenic global warming' in reply. But the Sceptics do raise reasonable doubt about some of the IPCC's numbers, so the authors re-examine the figures concerned – only to find that the crucial numbers are much more likely to be right than wrong.

So Morgan and McCrystal have a conclusion: we are causing climate change, and we had better do something about it soon.

But it's then my role, as reviewer of their review of the debate, to comment on how well they justify that conclusion. As someone who has been following the debate for twenty years, albeit as a layman, I noticed them making a few minor errors and accepting some dubious statements (from both sides) without quite enough care, but their evidence does seem to support their conclusion adequately. Even if some of the science is not settled, enough of it is settled to be convincing; Poles Apart does a good job of meeting its objective.

Scribe, August 2009, $35.00

Review originally published Jan 2010
Page created Aug 2010