Six Degrees summarises the likely consequences of global warming into a form that an interested layman like me can digest without being overwhelmed. The evidence that global warming is being driven by carbon dioxide from fossil fuels is straightforward and incontrovertible. I haven’t doubted that since I first saw the famous ‘hockey stick’ graph, showing how global temperatures have been shooting up since the industrial revolution. It’s been widely criticised by the self-professed sceptics, but none of the criticisms have stood up to scrutiny. New Scientist has helpfully published a breakdown of the arguments.
What is difficult to understand is not whether global warming is happening, but how much the world is likely to warm and what that will mean to us in the coming decades. Predictions are enormously difficult. Climate scientists can only observe the past and present, yet they must extrapolate from them into a future that will be fundamentally different. The planet is a massive and complex system, so the only experiment they can do is to wait and see if things get as bad as they predict.
Predictions are constantly updated. New measurements are made that give a better idea of how elements such as jetstreams, ocean currents and glaciers interact, and the whole process generates thousands of papers every year. The Intergovernmental Panel on Climate Change periodically summarises the evidence in documents that are tens of thousands of pages long. It would take years of dedicated research to distil it all down to a prediction of who it will affect and how.
Fortunately for a lazy layman like me, Mark Lynas has put in the years and done the distilling. He’s broken it down into chapters that each cover one extra degree of temperature rise, from 1°C through to 6°C above the baseline by 2100.
He starts by explaining that while air temperature may fluctuate by considerably more than that between day and night, a change of a few degrees in average global temperature is a very big deal. At the coldest point of the last ice age, the average global temperature was only six degrees lower than it is now. It was cold enough to freeze so much of the world’s water that North America was covered by one huge glacier that extended south of where the Great Lakes are now, and dropped the sea levels so far that you could have strolled across what is now the bottom of the North Sea from Holland to England if you could avoid irate mammoths.
It’s taken 18,000 years for the global average temperature to rise the six degrees from there to where it is today, yet the IPCC’s worst case scenario is that the next six degree rise could take less than 85 years. In a world with seven billion people and rising.
That, right there, is why I find this book so frightening.
The IPCC already regards a 2°C rise by 2100 as inevitable, which is bad enough. It will spread drought and forest fires across the tropics and subtropics, while storms that will make Hurricane Katrina and the cyclones that have been pounding the Philippines in recent years look like minor inconveniences pound coastal cities.
The upside, as Lynas repeatedly reminded me, is that a six degree rise is not inevitable. We have alternatives to burning fossil fuels, although it’s unfortunate that the environmental movement has set itself against nuclear power much more strongly than against fossil fuels, although fossil fuels are actually the largest danger to our future.
Six Degrees was published in 2007, so it’s been interesting to compare the trends he described to where they are now. The USA was the largest producer of carbon dioxide at the time he wrote it but it has now stabilised its emissions, largely due to replacing coal with more efficient methane produced by fracking. Meanwhile, the coal-fuelled behemoth of China has overtaken it, with India not far behind. Global emissions continue to rise.
That’s another reason to be frightened because even if global emissions were to stabilise tomorrow, so that we never burn more carbon per year than we do today, the level of carbon dioxide in the atmosphere would keep going up. It’s just not being removed from the atmosphere at the rate we’re putting it in.
One glimmer of hope that’s shone a bit brighter since 2007 is the progress in carbon sequestration technologies, which remove carbon dioxide from the atmosphere and return it to the earth’s crust. Until recently, there was even a plan for a ‘negative emission’ power station to open in 2020, which would burn woodchips and bury its carbon emissions under the North Sea. Unfortunately the project has foundered due to the UK’s cutting of subsidies for sustainable energy. The use of biomass fuel does beg the question of whether it will be the best use of agricultural land when droughts drive up food prices, but it’s encouraging that it’s technologically possible.
Frightening as Six Degrees is, it should be required reading for anyone who thinks they have an opinion on climate change. It is happening and it is terrifying. It threatens all the gains the human race has made in reducing world poverty I pontificated about a couple of weeks ago and to plunge us back into a global dark age from which we may never recover. Lynas reminds us repeatedly that it’s not too late to do something about it.
Let’s listen to him.