Louisa Pearson: Could geoengineers change our weather and halt global warming?

BACK in the 1960s, Soviet engineers came up with an inspiring idea for improving the harsh climate of the northern USSR. Melt the Arctic ice cap. It would mean goodbye Siberian permafrost, hello productive farmland.

Today the melting of the ice cap is viewed in a rather different light. Losing such a vast reflective surface is seen to be speeding up climate change, not to mention displacing polar bears to cities where they have to forage through rubbish bins instead of hunting seals. These days, all manner of schemes are being dreamed up to alter Earth's weather, but this time round the mission is to save the planet rather than to turn Siberia into a sizzling beach resort.

Option one involves using less resources, cutting down on CO2 and not leaving appliances on standby. This is a hard sell. So instead we move on to the "quick fix". Step forward the geoengineers. Once seen as being a bit loony, geoengineering is now talked about in hushed tones by respectable scientists. Options tend to involve either deflecting the sun's rays or draining off greenhouse gases. Towards the end of last year, the Institute of Mechanical Engineers produced a report on the subject. Topics discussed included using "artificial trees" to capture and bury CO2 underground; increasing the reflectivity of surfaces in cities to reduce temperatures (layman's translation: paint your roof white); and growing algae in tubes attached to buildings to absorb CO2 through photosynthesis.

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To be fair, this report is not suggesting a quick fix. The authors wrote: "Is there something we can do to buy time while we go about the business of a low-carbon transition, yet which doesn't distract us from that principal objective? The answer may be 'yes' and it is geoengineering."

A subsequent report from the Royal Society discussed using ships to vaporise seawater, which would then create clouds and potentially block out sunlight. Another option is launching sulphur dioxide particles into the upper atmosphere to deflect solar radiation. If you're thinking: "Wouldn't the sulphur cause acid rain?" you'd be right, and your concerns about these "stratospheric aerosols" damaging the ozone layer would be correct too. I envisage spacemen with giant cans of strong-hold hairspray, undoing our good work in weaning ourselves off CFCs.

Seemingly the sulphur dioxide option will require centuries of commitment, raising the question of who'll be doing the work, who's paying for it, and what happens if it all goes wrong. And on the subject of CFCs, they perfectly illustrate one of the problems with geoengineering. At the time of their creation, no-one foresaw that CFCs would cause a hole in the ozone layer. It seems ridiculous that a body spray could have such far-reaching repercussions. Who knows what unforeseen side-effects firing sulphur dioxide into the atmosphere might have.

Meanwhile, putting mirrors in space to deflect radiation isn't winning many thumbs-up because of the expense and energy required (is it me, or is it beginning to sound like an intergalactic beauty salon up there?). Artificial trees? At an estimated cost of 20 million each and tens of thousands being required in the UK alone, we may be better off plant the real thing.

As for deliberately causing more cloud-cover, that is never going to be a vote-winner in Scotland. So it seems we must continue to try to change our ways. While being secretly glad that the scientists are thinking about these things just in case we don't manage to get our act together.

• This article was first published in Scotsman on Sunday on 10 January, 2010.