When I was at the EGU meeting in Vienna in April, I attended a session on geoengineering, run by Jason Blackstock. During the session I blogged the main points of Jason’s talk, the key idea of which is that it’s time to start serious research into the feasibility and consequences of geoengineering, because it’s now highly likely we’ll need a plan B, and we’re going to need a much better understanding of what’s involved before we do it. Jason mentioned a brainstorming workshop, and the full report is now available: Climate Engineering Responses to Climate Emergencies. The report is an excellent primer on what we know currently about geoengineering, particularly the risks. It picks out stratospheric aerosols as the most likely intervention (from the point of view of both cost/feasibility, and current knowledge of effectiveness).

I got the sense from the meeting that we have reached an important threshold in the climate science community – previously geoengineering was unmentionable, for fear that it would get in the way of the serious and urgent job of reducing emissions. Alex Steffen explains this fear very well, and goes over the history of how the mere possibility of geoengineering has been used as an excuse by the denialists for inaction. And of course, from a systems point of view, geoengineering can only ever be a distraction if it tackles temperature (the symptom) rather than carbon concentrations (the real problem).

But the point made by Jason, and in the report, is that we cannot rule out the likelihood of climate emergencies – either very rapid warming triggered by feedback effects, or sudden onset of unanticipated consequences of (gradual) warming. In other words, changes that occur too rapidly for even the most aggressive mitigation strategies (i.e. emissions reduction) to have an effect on. Geoengineering then can be seen as “buying us time” to allow the mitigation strategies to work – e.g slowing the warming by a decade or so, while we get on and decarbonize our energy supplies.

Now, maybe it’s because I’m looking out for them, but I’ve started to see a flurry of research interest in geoengineering. Oliver Morton’s article “Great White Hope” in April’s Nature gives a good summary of several meetings earlier this year, along with a very readable overview of some of the technology choices available. In June, the US National Academies announced a call for input on geoengineering which yielded a treasure trove of information – everything you’ve ever wanted to know about geoengineering. And yesterday, New Scientist reported that geoengineering has gone mainstream, with a lovely infographic illustrating some of the proposals.

Finally, along with technical issues of feasibility and risk, the possibility of geoengineering raises major new challenges for world governance. Who gets to decide which geoengineering projects should go ahead, and when, and what will we do about the fact that, by definition, all such projects will have a profound effect on human society, and those effects will be distributed unequally?

Update: Alan Robock has a brilliant summary in the Bulletin of the Atomic Scientists entitled 20 reasons why geo-engineering might be a bad idea.

Join the discussion: