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Cloud-making plan to reverse global warming
Edinburgh University professor advocates revolutionary response to crisis
Jasper Hamill
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EVERY CLOUD could have a silver lining in the fight against global warming and the brighter, the better.

Professor Stephen Salter, a renowned engineer working at Edinburgh University, has hatched a plan to produce white clouds over the ocean to halt the catastrophic water heating associated with global warming.

In the worst-case scenario, where global "tipping points" such as the melting of the Arctic ice cap are reached, he claimed launching a fleet of cloud-producing drone ships could save Earth.

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Salter, who is famed for inventing the "duck", a device that generates power by bobbing on waves, said: "We've got an explosive with the detonator in it, and when one goes off, it could trigger other explosives. That's why we need to have a number of solutions. I don't mean that we should continue burning coal and then just fix the consequences, that would be terrible. Just as a revolver has many bullets, we need several ideas."

The brightness of a cloud, called its albedo, is directly related to how much heat it reflects, with white clouds more reflective than dark ones.

Currently, the ice caps reflect much of the sun's heat but if they melt, the dark ocean will absorb its energy and warm up, causing weather patterns to change. Salter's idea, which he formed in collaboration with John Latham, of the National Centre for Atmospheric Research in Colorado, is to build boats to sail the ocean and produce a spray of tiny water droplets around which white clouds can form. He suggested that around 400 of these wind-powered boats would be needed, at a cost of £100 million. However, the difficult part would be producing droplets small enough for clouds to form, a technique Salter has yet to master. His struggle has been a lonely one so far, and he holds little faith in government.

Salter said: "In the UK, there is one old aged pensioner, me, and one PhD student in Leeds working on cloud control, and that is it. Then there are politicians travelling the world, holding meetings to say how awful it is and the only outcome is that they organise another meeting to say the same."

Geo-engineering, a blue-sky discipline that aims to provide solutions to prevent or limit the damage caused by climate change, is unpopular in Britain, because the government prefers to stick to a policy of cutting emissions. The UK has been wary of attempts to control the weather ever since a disastrous 1952 experiment in Lynmouth, Somerset, when the RAF tested a rain-making technique that flooded the area, killing 35 people The Department for Environment, Food and Rural Affairs has never bankrolled geo-engineering. Thus, the sole source of funding for Salter has been from a TV channel, which built a prototype of his boat producing an artificial cloud.

A Defra spokeswoman said: "It is recognised that some large-scale geo-engineering schemes may have potential for reducing climate change. However, many of them are potentially high risk and there are significant concerns about their environmental side effects, as well as their technical feasibility, effectiveness and cost. So there is a need to consider the feasibility of geo-engineering options in more detail and Defra is looking into this."

Professor Anne Glover, chief scientific adviser for Scotland, welcomed Salter's plans and said the Scottish government would always fund "radical" thinking if the rationale was sound.

She said: "It's innovative science that is potentially very exciting. You can never stop scientists being inventive. Let's consider all options."

Environmental campaigners called for further cuts in levels of carbon dioxide in the atmosphere, but welcomed any fresh ideas. Duncan McLaren, chief executive of Friends of the Earth Scotland, said: "Stephen Salter's ideas should be explored alongside measures to drastically cut our emissions."

Professor Salter is speaking at 2pm, on Wednesday, at Craighouse Campus of Napier University