IT鈥橲 time to stop churning out ideas for repairing Earth鈥檚 climate and start working out which show the most promise so they can be tested. So says a researcher who is calling for an international organisation to rank all ideas to geoengineer the climate.
Various proposals have been put forward, from putting 鈥渟unshades鈥� in space to burying carbon dioxide. 鈥淭he ideas for how to change our climate keep getting pumped out. They get lots of column inches,鈥� says Philip Boyd of the National Institute of Water and Atmospheric Research in Dunedin, New Zealand. 鈥淢y concern is that we will reach a tipping point, people will ask what we are doing about it, and none of the schemes will have been tested.鈥�
鈥淲e will reach a tipping point, and none of the schemes will have been tested鈥�
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Boyd proposes that an international body such as the Intergovernmental Panel on Climate Change rank the schemes according to risk, cost, effectiveness and how quickly they could get off the ground (Nature Geoscience, ). By coincidence, the UK鈥檚 Royal Society launched such a study on Thursday.
Schemes that rely on biological mechanisms 鈥� for example, seeding oceans with iron to stimulate algae that would suck up carbon dioxide 鈥� will be the most prone to unknown side effects, says Boyd. Less risky would be ideas based on well-understood principles of physics and chemistry, such as 鈥渨ind scrubbing鈥�, in which chemicals are used to absorb carbon dioxide from the atmosphere.
