If you really want to go down the “technological fix” route with respect to climate change, which proposed schemes for cooling the planet offer the most bang? A new study by Tim Lenton and Naomi Vaughan at the University of East Anglia seeks to answer that question by looking at the various options on offer in terms of pure energy — how many watts per square metre of warming can they counteract?

Caveat: this is a study of bang pure and simple, not bang-per-buck and not oh-dear-that-bang-seems-to-have-blown-my-hand-off. Arguments against the various proposals will be the subject of another forthcoming paper. That said, the main take home message from this study is that schemes which evenly weaken the sunlight over the whole planet, either with particles in the stratosphere or spacecraft in orbit, are the winners. Brightening clouds has some serious potential, too, as do truly massive forestry schemes; but ocean-fertilisation techniques, of which a variety have been discussed, are largely ineffectual (which is to say they deal with only about 10% of the forcing due to greenhouse gases already in the atmosphere, to say nothing of those as yet to be added). Burying biochar, as recently recommended by Lenton’s mentor Jim Lovelock, isn’t that much better (though it has other benefits too).

More detail in a longer post over at Climate Feedback. Or if you want to go elsewhere the story is covered by the Eastern Daily Press (local paper for the University of East Anglia) and the Natural Environment Research Council’s web site. The wires have it too (AFP|Press Association|Reuters)