Fossil fuel-free in 20 years?转自《中外对话》

George Monbiot
July 12, 2007
Prospects for renewable power are promising. But it means nothing, argues George Monbiot, if the public interest is drowned by corporate power.
“The government must immediately commission studies to discover how much of our energy could be produced without fossil fuels, set that as its target and then turn the economy round to meet it.”
Reading a scientific paper on the train recently, I found, to my amazement, that my hands were shaking. This has never happened to me before, but nor have I ever read anything like it. Published by a team led by James Hansen at NASA, it suggests that the grim reports issued by the Intergovernmental Panel on Climate Change (IPCC) could be absurdly optimistic.
The IPCC predicts that sea levels could rise by as much as 59 centimetres this century. Hansen’s paper argues that the slow melting of ice sheets that the panel expects doesn’t fit the data. The geological record suggests that ice at the poles does not melt in a gradual and linear fashion, but flips suddenly from one state to another. When temperatures increased to between two and three degrees above today’s level 3.5 million years ago, sea levels rose not by 59 centimetres but by 25 metres. The ice responded immediately to changes in temperature.
We now have a pretty good idea of why ice sheets collapse. The buttresses that prevent them from sliding into the sea break up; meltwater trickles down to their base, causing them suddenly to slip; and pools of water form on the surface, making the ice darker so that it absorbs more heat. These processes are already taking place in Greenland and west Antarctica.
Rather than taking thousands of years to melt, as the IPCC predicts, Hansen and his team find it “implausible” that the expected warming before 2100 “would permit a west Antarctic ice sheet of present size to survive even for a century”. As well as drowning most of the world’s centres of population, a sudden disintegration could lead to much higher rises in global temperature, because less ice means less heat reflected back into space. The new paper suggests that the temperature could therefore be twice as sensitive to rising greenhouse gases than the IPCC assumes. “Civilisation developed,” Hansen writes, “during a period of unusual climate stability, the Holocene, now almost 12,000 years in duration. That period is about to end.”
I looked up from the paper, almost expecting to see crowds stampeding through the streets. I saw people chatting outside a riverside pub. The other passengers on the train snoozed over their newspapers or played on their mobile phones. Unaware of the causes of our good fortune, blissfully detached from their likely termination, we drift into catastrophe.
Or we are led there. A good source tells me that the British government is well aware that its target for cutting carbon emissions -- 60% by 2050 -- is too little too late, but that it will go no further for one reason: it fears losing the support of the Confederation of British Industry (CBI). Why this body is allowed to keep holding a gun to our heads has never been explained, but the United Kingdom’s new prime minister, Gordon Brown, has just appointed Digby Jones, the CBI’s former director-general, as a minister in the department responsible for energy policy. I don’t remember voting for him. There could be no clearer signal that the public interest is being drowned by corporate power.
The government’s energy programme, partly as a result, is characterised by a complete absence of vision. You can see this most clearly when you examine its plans for renewables. The European Union has set a target for 20% of all energy in the member states to come from renewable sources by 2020. This in itself is pathetic. But the British government refuses to adopt it: instead it proposes that 20% of our electricity (just part of our total energy use) should come from renewable power by that date. Even this is not a target, just an “aspiration”, and we are on course to miss it. Worse still, the government has no idea what happens after that. I recently asked whether it had commissioned any research to discover how much more electricity we could generate from renewable sources. It has not.
It’s a critical question, whose answer -- if its results were applied globally -- could determine whether or not the planetary “albedo flip” that Hansen predicts takes place. There has been remarkably little investigation of this issue. Until recently I guessed that the maximum contribution from renewables would be something like 50%: beyond that point the difficulties of storing electricity and balancing the power grid could become overwhelming. But three papers now suggest that we could go much further.
Last year, the German government published a study of the effects of linking the electricity networks of all the countries in Europe and connecting them to North Africa and Iceland with high-voltage direct-current cables. This would open up a much greater variety of renewable power sources. Every country in the network would then be able to rely on stable and predictable supplies from elsewhere: hydroelectricity in Scandinavia and the Alps, geothermal energy in Iceland and vast solar thermal farms in the Sahara. By spreading the demand across a much wider network, it suggests that 80% of Europe’s electricity could be produced from renewable power without any greater risk of blackouts or flickers.
At about the same time, Mark Barrett, of University College London, published a preliminary study looking mainly at ways of altering the pattern of demand for electricity to match the variable supply from wind and waves and tidal power. At about twice the current price, he found that we might be able to produce as much as 95% of our electricity from renewable sources without causing interruptions in the power supply.
Now a new study by the Centre for Alternative Technology, in Wales, takes this even further. It is due to be published very shortly, but I have been allowed a preview. It is remarkable in two respects: it suggests that by 2027 we could produce 100% of our electricity without the use of fossil fuels or nuclear power, and that we could do so while almost tripling its supply; our heating systems (using electricity to drive heat pumps) and our transport systems could be mostly powered by it.
It relies on a great expansion of electricity storage: building new hydroelectric reservoirs into which water can be pumped when electricity is abundant, constructing giant vanadium flow batteries and linking electric cars up to the grid when they are parked, using their batteries to meet fluctuations in demand. It contains some optimistic technical assumptions, but also a very pessimistic one: that the UK relies entirely on its own energy supplies. If the German proposal were to be combined with these ideas, we could begin to see how we might reliably move towards a world without fossil fuels.
If Hansen is correct, to avert the meltdown that brings the Holocene to an end we require a sort of political “albedo flip”. The government must immediately commission studies to discover how much of our energy could be produced without fossil fuels, set that as its target and then turn the economy round to meet it. But a power shift like this cannot take place without a power shift of another kind: we need a government which fears planetary meltdown more than it fears the CBI.
Homepage photo by ?/font] Rob Welham
Copyright Guardian News & Media Ltd 2007
http://environment.guardian.co.uk/