Geo-engineering might help tackle climate change but do we really want every cloud to have a silver iodide lining?

At the moment, geo-engineering is not on the agenda for Copenhagan - but one can see why scientists are arguing that we use it to tackle climate change, writes Robert Colvile.

Robert ColvilePublished: 6:46AM GMT 04 Nov 2009

If you've ever had a hankering to play God, send a CV to the Beijing Weather Modification Office. There, with a wave of the hand – or rather, a judicious dusting of silver iodide – the servants of the Chinese state believe they can force the clouds to unload moisture as and where they choose, bringing rain to parched crops or guaranteeing clear skies for occasions of supreme national importance, such as the Beijing Olympics or last month's National Day celebrations.
This weekend brought a reminder of the agency's work: in seeking to end a minor drought, the Chinese claimed to have burst the heavy clouds over the area, dumping 16 million extra tons of snow and forcing the closure of the capital's airports. The reaction from the West ranged from bemusement to admiration. But what would we do if China attempted to reorder the heavens on a global scale?
Over the next month and a half, the world's leaders will be attempting to hammer out a deal on carbon emissions, to tackle the growing threat of climate change. But already, some scientists are arguing that such a deal will come too late, or achieve too little, and that we must turn to technological fixes.
In other words, as well as changing our behaviour, whether by taking fewer flights or abandoning eating beef (as fewer cattle means less methane), we should investigate "geo-engineering": reflecting the sun's rays by painting roads and cities white, or launching mirrors into space; encouraging the growth of carbon-capturing algae in the oceans by seeding them with iron; lowering those oceans' surface temperatures by drawing cooler water from the depths; using sea water to create artificial clouds to reflect the sunlight; scrubbing carbon from the air using artificial trees; or setting up artificial volcanoes to pump sulphur into the atmosphere.
This last proposal has been receiving particular attention recently, after it was included in Steven Levitt & Stephen Dubner's new book SuperFreakonomics. They profiled Nathan Myhrvold, a former Microsoft executive "so polymathic as to make an everyday polymath tremble with shame", whose Seattle-based firm Intellectual Ventures reckons it could solve global warming at a bargain-basement price by injecting sulphur into the upper atmosphere, mimicking the volcanic eruption of Mt Pinatubo in the Philippines in 1991, which temporarily lowered world temperatures by half a degree.
For each of these systems, grand claims are made. Myhrvold's team thinks that by rigging 18-mile-long fire hoses to helium balloons, and using the waste sulphur from oil extraction, they can get a planet-saver in place at a start-up cost of $150 million, plus $100 million a year in running costs – a bargain, considering Lord Stern's warning that between 1 and 2 per cent of global GDP will be needed to fight climate change. Hashem Akbari, who has been urging the world's cities to get out the pots of white paint, thinks his plan could offset a decade's worth of increased emissions.
The objections, of course, are equally fervent. First, the world's climate is a terrifyingly complex system, full of barely understood tipping points and feedback loops. Even though rough predictions can be made, we are only just beginning to work out the ways in which, for example, atmospheric water vapour magnifies the effects of carbon emissions. Tinker in the wrong way and you'll get nastier and, in some cases, more permanent consequences than a few snowbound runways.
Second, studies suggest that many of the proposed systems might not work, would have less of an effect than hoped, or would be prohibitively expensive. And third, given that humanity got the planet into this mess, it seems a bit of a cheat to rely on technology to fix it without making us suffer for our sins.
In a way, however, the flaws and merits of the various systems are beside the point. The squabbling surrounding Copenhagen shows that it will be a mammoth task to get the world's 200-odd governments to agree on specific measures to tackle climate change. Even if they do, coralling more than 6.7 billion people into modifying their lifestyles to suit could be a tall order. And even if emissions were slashed tomorrow, all the carbon we've pumped into the atmosphere would still be sitting there, helping to heat up the planet.
It is with these obstacles in mind that the Royal Society called for the world's governments to investigate geo-engineering as a "Plan B", through the creation of a £100 million fund to evaluate the various suggestions on offer. At the moment, it is nowhere on the Copenhagen agenda. But it's easy to see the sort of quick and easy solution offered by geo-engineering and its prophets becoming terribly attractive to one government or more, a few years down the line, despite the risks.
If a China beset by the effects of climate change decided to construct one of Myhrvold's sulphur spreaders unilaterally, would the accusations about "weapons of planetary destruction" be far behind? That would be enough of a mess to make last weekend's weather in Beijing look like a snowstorm in a teacup.