Wednesday 24th December, 2008

I've been reading Jonathan Neale's excellent book Stop Global Warming: Change the World (Bookmarks, 2008).

Global warming is happening and will cause significant loss of life due to increases in extreme weather and changes in the agricultural fertility of different regions. The worse threat, however, is abrupt warming, an event which is now known to have happened more than 20 times in the last 100,000 years. Abrupt change of this type would cause extreme climate chaos and hundreds of millions of deaths. Abrupt warming will happen if we reach a point where various feedback mechanisms combine and reinforce each other (methane release, ice melt, rainforest death, etc.). This is likely to happen when the current process has lead to an increase of between 2 and 5 C (so far it has lead to an increase of 0.7 C). In order to hold the current warming process to 2 degrees or less (and allowing for the various uncertainties in the predictive models), we have to cut our carbon emissions by between 60 and 70%, and we have between 5 and 30 years within which to do it.

Unless we can recapture the carbon? Somehow suck it out of the atmosphere, or perhaps create some other mechanism to screen us from the sunlight? There are a number of things to say about this. The one that leaps to my mind, as a practising scientist, is that scientists are, like everyone else these days, in the business of selling their work in order to get funded to do more work (and to continue eating, incidentally). As a practising engineer, I can imagine buying a house that wasn't built yet — people already know well how to build houses — but I can't for the life of me imagine buying a revolutionary and untested technology on the say-so of a few very interested parties, less still betting the future of the air that I breath on that gamble.

A second problem with technological solutions to global warming is the global nature of the problem. Science is more than experiment, but nonetheless experiments are key to building up enough trust in theoretical results that we permit their use in engineering solutions. How can we have a global experiment? Got a spare planet, anyone?

So: our house is in danger of burning down, and we need to put the fire out, and not put our hopes in a "smoke and ashes to bricks and mortar" technology which may or may not come along one day.

What about population increase, and consumption increase in previously poor countries like India and China? Two things. First, the probable increase in population is smaller than it is often painted — perhaps between 18 and 28% by 2030. Second, the increase is predominantly in areas where emissions are low. "Doubling the population of Bangladesh by another 140 million people would increase global emissions by another 0.001 percent" [Neale, op cit, p.33]. (Do the same in the USA and the increase would be 10% — but there population is falling.) Do the sums and we can still avoid abrupt warming in face of likely population increase and consumption increase if we raise our requirement for cutting carbon emissions to around 80-85%.

It is something of a shame, then, that the blind hand of the market is in charge, and that the existing corporate hierarchy finds carbon cutting insufficiently profitable...


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