Professional Engineering

A year and a half on from authoritative reports by the IMechE and Royal Society on geo-engineering, experts on this controversial and unproven science – which could have the potential to reverse the effects of climate change – believe that not enough is being done to develop it.

Professor John Shepherd, of the University of Southampton’s National Oceanography Centre and a Fellow of the Royal Society, believes that £100 million should be devoted to researching geo-engineering schemes over 10 years– instead of the £3 million of Engineering and Physical Sciences Research Council money given to it at present. “That’s 3% of what we’ve suggested – and I think we ought to have the other 97%,” says Shepherd.

Tim Fox, head of energy and climate change at the IMechE, concurs. “We need to focus very quickly on the practical geo-engineering solutions – ones where there is a consensus that they offer real possibilities,” he says.

Geo-engineering schemes are potential ways of modifying the earth’s climate through technology. The proposed ideas fall into two groups: schemes that would sequester CO2 from the atmosphere, and techniques for managing solar radiation to deflect sunlight. Geo-engineering may well represent the last chance in the climate change saloon and has many detractors, but others believe it would be foolish not to consider using it when emissions of greenhouse gases continue to rise and runaway global warming is a real possibility. 

The solar radiation management (SRM) techniques proposed include spraying sulphur into the stratosphere. It is thought that this could mimic the effects of volcanic eruptions, such as that of Mount Pinatubo in the Philippines in 1991, which released large quantities of aerosols into the atmosphere with the effect of temporarily cooling the planet. British engineer Stephen Salter, meanwhile, has done a lot of work on a scheme that could increase the albedo of clouds – the extent to which they reflect sunlight – by seeding them with seawater droplets. In the US, Professor Roger Angel of the University of Arizona has even proposed launching trillions of mirrors into space to form a sunshade, blocking out 2% of the sun’s rays.

Direct CO2 removal from the atmosphere is the geo-engineering scheme favoured by Fox at the IMechE. US physicist Klaus Lackner has proposed capturing CO2 through the deployment of hundreds of thousands of mechanical trees built with materials that absorb greenhouse gases.

Fox says: “Artificial trees offer the best potential geo-engineering activity, and really we should consider them as a form of CO2 mitigation. It’s one step beyond carbon capture and storage being used at a power plant.” The IMechE considers geo-engineering to be a crucial part of a three pronged attack on climate change which also includes mitigation of emissions and adaptation.

Some in the media have suggested that development of geo-engineering could be part of a conspiracy to enable fossil fuels to continue to be burned with impunity, but Fox insists that engineers looking at geo-engineering have no desire to see it replace efforts directed at mitigation.