Last month I wrote that geoengineering proposals had practically made the scientific mainstream, gracing a special issue of one of the Royal Society’s journals. With global emissions steadily rising and policy responses slow to take hold, scientists have begun to call more loudly for research into the last-ditch technological fixes that might – or might not – be able to reset a rapidly changing climate.
The journal’s special issue turns out to have been just a preliminary move for the UK scientific academy. Today the Society announced it is launching a project to review and compare, on paper, the merits of different geoengineering schemes.
Mentioned in the press release are some of the classics: reflecting sunlight with space-based mirrors, pumping cooling aerosols into the atmosphere, and fertilizing the ocean with iron to create carbon-sucking plankton blooms. (Trials of that last one by startup company Climos, who hope to make carbon-credit money off it, are up for consideration by international regulators this week, Reuters reports.) A working group will assess such ideas’ feasibility – “separate the science from the science fiction”, in the words of chair John Shepherd – as well as the huge side effects we could incur by trying to manually turn the thermostat on an incompletely understood planet. A report will be out in mid-2009.
Philip Boyd of New Zealand’s University of Otago demanded an assessment much like this only a few days ago in a Nature Geoscience Commentary (subscription), as The Great Beyond reported. It’s been 15 years, says Boyd, since geoengineering ideas were comprehensively scrutinized and ranked according to their promise (by Keith and Dowlatabadi in Eos, Transactions, American Geophysical Union, 1992, if you’re wondering). Here is Boyd’s example of what he’s looking for (more color denotes a higher ranking – this is one for the imaginative graphics file).
We need a ranking to prioritize research funding, Boyd argues, and improved understanding of the Earth system in the last decade and a half sheds a lot of new light on the schemes – particularly on their problems (see e.g. this study of aerosol cooling). In that respect, the Royal Society’s report on geoengineering seems likely to end up underlining drawbacks as well as recommending what to research – much like its biofuels assessment did.
Image: Comparison of aspects of five geoengineering proposals. Reproduced from Nature Geoscience 1, 722-724 (2008).