Geo-Engineering: Five Experts Debate

From Seed magazine, an excellent discussion of the pros and cons of geo-engineering the climate to avoid a potential disaster, by five recognized experts.

Here's "the prompt," as the kids say:

In June the National Academies’ climate panel will convene to examine
whether geo-engineering fixes are technically and economically
feasible—and whether they can be carried out without unwanted
environmental side effects. As pre-Copenhagen process limps along,
struggling to meet scientifically defined targets, how would you advise President Obama on geo-engineering? Is it too risky to consider? Or too risky to ignore?

And here's the answer that makes the most sense to me, from Ken Caldeira at Stanford:

The term “geo-engineering” has referred to a mixed bag of proposals,
ranging from whitening roofs to whitening skies, from engineered crops
to fertilized oceans, so little can be said of “geo-engineering
proposals” in general. But there is one category of proposal that
deserves special attention, and that is proposals that can cool the
Earth quickly in the face of a climate emergency.

In every single greenhouse gas emissions scenario considered by the
IPCC, the Earth keeps heating throughout this century — even in the
most optimistic scenarios in which we make a rapid transition toward
renewable energy sources. And, of course, actual emissions exceed even
the most pessimistic of the IPCC scenarios.

If the heating of our planet becomes intolerable in this century,
direct intervention in the climate system would be the only way to
start the Earth cooling soon…It is critical that we research our climate emergency backup system
before we need to deploy it. Therefore, it is critical that we
investigate options with the potential to initiate global cooling
within years or decades. We need to know, before a climate crisis
occurs, whether such a system could reduce risk or would merely make
things worse.

Last December, at a panel at the AGU called Geo-Engineering Through Solar Radiation Management, I heard David Mitchell of the Desert Research Institute make an argument for serious research into the possibilities. Yes, his work on cirrus clouds could benefit from more research dollars, but he said that it would take in the range of ten years to assess the science, at a relatively modest cost, much much less than what we are spending now on observing global warming. Sounds about time to start to me.