Paint it white: what role should geo-engineering play in tackling climate change?

Peter Madden asks how much we should manipulate our future.

Might we be living in ‘white cities’ in future decades? Will our quest to cool the planet see us constructing large-scale modern versions of the traditional Greek and Spanish villages, whose pale colour reflects back the sun’s rays?

It may sound far-fetched, but that’s the vision of Steven Chu, the US Energy Secretary, who recently suggested painting all of the world’s roofs white.

He’s not the only one looking to geo-engineering as a way to tackle climate change. Two years ago, Richard Branson launched a $25 million prize for technology to remove at least one billion tonnes of carbon a year from the atmosphere – which is still looking for a winner. And, as new data shows emissions reaching a dangerous tipping point, governments around the globe are paying much more attention to the potential of such ‘techno-fixes’.

If we see some of these proposed geo-engineering solutions taking off, our world could look very different. Our coastlines could be dominated by huge carbon dioxide capture towers, which pump CO2 down into saline aquifers or into greenhouses to encourage the growth of fruit and vegetables. Solar powered robot ships might traverse our oceans, spraying a fine mist of seawater into the air to create clouds, which reflect back sunlight, so shielding the oceans from the sun.

Behind these ‘sci-fi’ technologies lie two approaches to tackling climate change:

• removing carbon dioxide from the atmosphere on a large scale (eg seeding the ocean with chemicals that absorb CO2 in reaction)
• reducing global warming (eg by growing specially bred, light coloured crops).

The methods don’t all involve high-tech manipulation. Biochar, for example, is a simple way of making charcoal to sequester carbon in soil – and interest and investment are proceeding apace [see ‘Burn the trees to  save the world?’].

But it’s no surprise that the appropriateness of geo-engineering is hotly contested. Advocates believe we should intervene forcefully to control our already destabilised climate, whatever it takes. Opponents argue that tinkering with natural systems could backfire – and worry that endorsing the concept might scupper international climate negotiations.

I’m sure we will see geo-engineering happen in some form. Technologies to sequester carbon will no doubt be deployed if the concentration of CO2 in the atmosphere overshoots a critical point. These techniques could buy us critical time in the face of feedback cycles, where increased heat in the atmosphere further increases greenhouse gas emissions from natural sources, such as methane from melting permafrost.

We just need to make sure these enticing new technologies don’t divert attention and resources from existing, if less exciting, approaches that are already proven to work.

White carrots, anyone?

Peter Madden is Chief Executive of Forum for the Future.

8 September 2009

Peter Madden

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