ABSTRACT
In the two years of writing this book, predictions from climate science have become steadily more pessimistic. The IPCC Fourth Assessment Report in 2007 predicted a sea-level rise of only around 50cm over the coming century, and a slow decline of Arctic sea ice cover. These predictions were far too optimistic. Now, a summer ice-free Arctic in a decade or two seems likely, and if the break-up of the Greenland ice cap accelerates, sea levels could rise by metres per century, to match the dramatic pace of rising at the end of the last ice age. As sea ice and snow cover in the northern hemisphere recede, albedo, or reflectivity of land and water surfaces, declines, so they absorb more solar radiation and warm faster during lengthening summer seasons. Already rapid northern warming will accelerate, releasing ever more methane from thawing peat bogs in an additional carbon ‘feedback’, which in turn generates still more warming. While the oceans are warming much more slowly than the atmosphere, their capacity to absorb carbon dioxide is also likely to decrease. The probable doubling of pre-industrial concentrations in the next few decades, under current, weak abatement plans based on the IPCC Report, could easily trigger irreversible methane release and collapse of the ice caps. This in turn could push temperatures to the top of (or beyond) the IPCC range of up to five or six degrees over pre-industrial levels. The result would be the collapse of our civilization, leaving much of the Earth’s surface uninhabitable and displacing or destroying most existing species, including the human population.
