Can geo-engineering rebuild the planet?

As we grapple with the problems of global warming, the standard prescription – cutting greenhouse gas emissions – is proving problematic. “I cannot see that we will be able to keep carbon levels low enough to prevent catastrophe,” says Professor Brian Launder, of the University of Manchester. “Over the past five years, emissions have gone up, not down.”

Which means that “geo-engineering” – using technology on an almost unimaginable scale to tinker with the environment and correct our mistakes – could move from fantasy to necessity.
Most of the schemes suggested, there and elsewhere, involve dramatic alterations to the Earth’s weather systems, whether by deflecting the Sun’s rays, removing carbon from the atmosphere or cooling the oceans. Prof Lovelock has come up with one of the most ambitious: he and Professor Chris Rapley, from the Science Museum, would like a system of pipes to be held vertically below the ocean’s surface. These tubes, each 100 metres long, would draw cold water from below; wave action would then mix four tons of cooler water per second into the ocean at the surface. Cooler oceans mean a cooler planet, while the nutrient-rich water brought up from the bottom could encourage algal blooms, which use carbon to grow and thereby remove it from the atmosphere.

But as intoxicating as such ideas are – and as tempting as a “quick fix” to the climate would be – they are not the finished article. Not only would the costs be enormous, but in a recent paper in Atmospheric Chemistry and Physics Discussions, Dr Tim Lenton of the University of East Anglia compared the possible effectiveness of 17 different geo-engineering techniques, and found severe problems with many of them.

Telegraph