Geoengineering must be researched before it can be employed, say experts

Geoengineering has come to be known as the Hollywood solution to climate change: a triumph of last-minute human intuition, against all odds. From huge sun shields launched into space to artificial trees that can soak up excess carbon, Geoengineering is an insurance against the possibility that all our efforts to control carbon emissions come to nothing.

This is no longer doom-mongering. According to the Royal Society's September 2009 report on the viability of geoengineering, although reducing greenhouse gas emissions remains a priority, there is a 50 per cent chance that all our efforts up to now will not be enough to prevent temperature rises of 2 °C, which some scientists say could "wreck" the Amazon rain forest, produce "extreme weather" conditions in the Caribbean and threaten Latin American water supplies as well as food yields in Asia.

The safety and viability of a host of geoengineering solutions should be tested in advance, concluded the Royal Society, so that the world is ready to deploy them immediately. "We are already staring 1.6 °C in the face," says John Shepherd, chair of the Royal Society group that produced the report.

Or in the words of Tim Kruger, founder of Oxford Geoengineering, a research body set up to continue the Royal Society's work, geoengineering is an "airbag for climate change". It's not something you would ever want to use, says Kruger, and if you do have to use it, it is pretty uncomfortable. "But you're rather glad you have it in the event of a crash."

Kruger takes great care to appear objective. "The institute is advocating that research is required, but not advocating geoengineering itself," he says. This stance is partly down to geoengineering's controversial status. Its critics point to the dangers of playing God, particularly with the earth's climate, which is nuanced and sensitively balanced. Green lobby groups such as Greenpeace believe Geoengineering is only being seriously considered because the world lacks the political consensus to agree on how best to wean itself off carbon. A scientific solution to climate change, say environmentalists, will not solve the root cause of the problem: our addiction to carbon.

But while climate change deniers are fond of using scientific uncertainty to strengthen their cases, Kruger says that doubt actually bolsters the case for geoengineering research. There are two main questions that need answering, he says. One, is an 80 per cent reduction in carbon emissions achievable? Two, if we do achieve it, will that stave off the worst effects of climate change? "Even if those reductions are technically and politically achievable, no one knows what the impact will be," he says.

Geoengineering is an insurance policy, says Kruger. "We have to plan on the basis that we will get a worse response from the climate than we are expecting. It was only a few years ago that the policy in the UK was for a 50 per cent reduction by 2050. Now we're looking at an 80 per cent reduction by 2050." As science advances, it could be that we need 90 per cent, 100 per cent, or even 120 per cent, he says. If those targets do increase, "then all the wind farms and solar panels won't [be enough to] draw the carbon dioxide out of the atmosphere. Those technologies... don't turn the clock back, they just slow it down."

Kruger's objectivity is also rooted in fair play. As well as his day job running Oxford Geoengineering, he is also involved in an open source geoengineering project called Cquestrate. The idea is that by first heating limestone to a high temperature to remove the carbon dioxide, and then pouring the lime into the sea, it will react with the carbon dioxide already dissolved in the seawater. This has two effects: first, it allows the seawater to absorb more carbon dioxide from the atmosphere, and second, it changes the Ph level of the water, which thanks to increasing levels of carbon has over time become rich in carbonic acid-too acidic an environment for coral, and many hard-shelled sea creatures, to survive.

There are many other competing geoengineering techniques. Most fit into two distinct categories: solar radiation management, which covers all attempts to reflect more sunlight back into space, and carbon dioxide removal, of which Cquestrate is one of many different approaches. "As someone who has been researching a particular technique, I have a perception at least, of bias," says Kruger. "We need to look at all geoengineering ideas because they have various advantages and disadvantages. You need to understand how they compare."

Many of the ideas originate in the US, but there are a few UK inventions, too. Slightly less radical than Kruger's plan is Stephen Salter's idea of spraying seawater into the air to encourage the build up of marine stratocumulus clouds, which are good at reflecting sunlight back into space. Professor Salter, of Edinburgh University, advocates using wind-powered, remote-controlled ships to spray minuscule droplets of seawater into the air, encouraging the creation of "seeds", around which large, white stratocumulus clouds can form.

Salter's technique won't clear the atmosphere of its excess carbon dioxide, but like many of its rival ideas, it could buy us time. Kruger says treating the root cause of the problem remains a priority. "The Stern review identified that industry is not paying for the pollution it causes. The damage done is $85 per tonne of Co2. Drax power station emits over 12,000 tonnes of carbon dioxide per million dollars of turnover," he says. "If you multiplied the 12,000 tonnes by 85 you would be causing over a million dollars of damage per million of turnover. Under the principle that the polluter pays compensation, that would not be economically viable."

Geoengineering is a young industry, says Kruger, who has enlisted the help of Sir David King, former Chief Scientific Adviser to the UK government and former Shell chairman Sir Mark Moody-Stuart, to serve on the research firm's advisory board. Part of Oxford Geoengineering's role will be "building bridges" to ensure that governments, NGOs, businesses and academics have access to science-backed research. "We need to create networks between academics," says Kruger. "We need to identify the key areas we need to research and work out how the funding can come in without causing a conflict of interest.

The other key target is engagement, he says. "Geoengineering is a scary topic. We need to make sure there is clear communication and ensure that we don't go down the same route as GM and nuclear." Shedding the Hollywood tag would be a useful start.