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Editor’s Note: 2014 was officially the hottest year on record. Since 2000, the world has experienced 14 of the 15 hottest years on record. And today, the American Meteorological Society released a report on the state of climate in 2014, which noted that last year greenhouse gases continued to climb, sea surface temperatures hit a record high, the global sea level hit a record high and the number of tropical cyclones increased.
What, you ask, can be done to address climate change?
A controversial, but cheap solution of last resort has emerged known as “solar radiation management.” A geoengineering technique, it would shoot particles into the sky to reflect sunlight back to space.
“The central idea is to make the planet a little bit more reflective, which tends to cool it down, because it will absorb less sunlight. And that will partially and imperfectly compensate for the buildup of greenhouse gases like carbon dioxide, which are tending to trap heat and make the earth warmer,” says Harvard environmental scientist David Keith, who works at the intersection of environmental science, energy technology and public policy.
Economics correspondent Paul Solman sat down with David Keith to better understand solar geoengineering and its potential geopolitical and economic effects. Tune in tonight to watch Making Sen$e’s segment on the economic consequences of climate change. The text of the following conversation has been edited and condensed for clarity and length.
— Kristen Doerer, Making Sen$e Editor
Paul Solman: Is solar geoengineering a solution to climate change?
David Keith: It’s certainly not a solution if by solution you mean that solar geoengineering is the only thing that could be done. If you do not bring the emissions of carbon at the atmosphere to zero, you can’t have a stable climate. It’s really as simple as that. And I think a lot of policy is being confused with crazy assumptions that it’s all one thing or another. The important question about solar geoengineering is: Would it make sense to do a small amount of it to reduce risks over the century in addition to cutting emissions?
Paul Solman: But as I understand it, once you go down this path, a rich person could send up a bunch of Lear jets emitting sulfates to bounce the rays back towards the sun. That could have dramatic consequences one way or the other.
David Keith: So it appears that it’s cheap enough that, in principle, it’s within the realm of possibility for the most wealthy people. But I think that’s actually a nonsense scenario. In practice, this would quickly become an issue of state negotiation and state power, not of individuals.
Paul Solman: What about a rogue individual who domiciles in the Cayman Island or something like that?
David Keith: I think it’s very implausible that it would be done on large scale by a single person — a Goldfinger.
Paul Solman: But might there be a state, China for example, that comes to the conclusion that this is better than nothing — that it ought to do it at least for a while.
David Keith: That’s much more plausible. I think the way this is actually most likely to happen is that some coalition of states decides that their risk of doing this is small compared to the benefits. They’re not doing it as an alternative to cutting emissions, but as a way to reduce risks to the humans most affected by climate change, especially the poor, and to ecosystems worldwide. And in that case, if it’s true that in fact the benefits are widespread and the risks aren’t very big, a likely outcome would be that other states loudly say, “We decry this unilateral action.” And privately they say, “We’re really happy somebody’s doing it.”
Paul Solman: Do you think that’s going to happen?
David Keith: It’s certainly plausible. I would say it’s more likely than not that people will use this as a way to reduce climate risks. If the current science as we now know it turns out to be roughly correct, then it looks like that it substantially reduces climate change on a region-by-region basis globally. So it reduces crop losses for the poorest and reduces the rate of melting for the big ice sheets and sea ice. And those are things people actually care about. So it’s pretty likely in my view that if that science is borne out, then people will in some form take the opportunity of reducing risk that way. Not as a substitute for cutting emissions, but in combination with cutting emissions.
Paul Solman: And what are the risks of doing this?
David Keith: There’s a whole series of risks. There’s the question of, what are the specific technical risks that come from whichever way people might try to reflect away some sunlight. We’re building experiments to actually test this in the stratosphere. So that might be sulfuric acid in the stratosphere, or sea salt sprays in the lower atmosphere, or what have you. All of those things will have individual specific risks. Then there’s the question of the efficacy of how well reflecting away sunlight compensates for the risk of CO2 build up. And the answer is quite imperfect, but the current evidence suggests that in fact it does a lot. That it might reduce surface climate changes by say, three quarters on a region-by-region basis globally. And that’s a gigantic benefit to people and ecosystems.
Paul Solman: OK, so what has the U.S. done to regulate the environmental risks?
David Keith: The United States Clean Air Act, which has regulated environmental pollution into the atmosphere, cost a lot. At the peak, it cost .08 percent of GDP. It has added or will have added by, say, 2020 almost a year to the life of the average American. It will have made us live a year longer by removing the pollutants that kill us. It’s the single probably most impactful healthy thing that the American government has done in the last quarter of century.
Something in the order of say, 20,000 to 60,000 Americans die a year from air pollution from our power plants, our cars, etc. Globally, about 3 to 6 million people die every year. It causes heart disease, asthma, etc. Air pollution is the single, biggest environmental risk that there is.
Paul Solman: Are any governments doing anything to combat climate change as whole and not just pollution?
David Keith: The United States and a lot of other countries now, even China, have made huge progress cutting back on local air pollution which kills people. Why haven’t we made the same progress on climate? When you put air pollution in the atmosphere, it only lasts for days. So if you a make a political deal, let’s say, to cut pollution in L.A, it costs real money. Everyone gets a little poorer, but people see the air become cleaner in their lifetimes. And that’s a political deal people can buy and they’re buying now in Beijing. But for climate, if we cut emissions, almost all of benefit comes globally, and it will come over the entire century. And that’s a much harder political deal, because you may do the right thing and cut your emissions, but you have no confidence somebody else will. And they think the same about you. That’s the underlying reason why it’s really hard to get a deal on climate.
The big risks of this technology fundamentally aren’t technical. They’re political. They’re the risk of how it gets used in a divided world. How do we set the thermostat in a world, where we have many different countries and many different interests and it’s really cheap to adjust the thermostat? In my view, all the really scary outcomes from geoengineering come when some country wants the climate one way and other countries want it another way. And they essentially fight over that.
Paul Solman: But who would be in favor of more global warming?
David Keith: I think no major country will be in favor of more global warming, but there are many ways it could really go off the rails. Let’s say China is concerned about weakening the strength of its monsoons. And let’s say they try this kind of geoengineering where they make the clouds wider off their coast, which might actually make the monsoon stronger. And Indian scientists believe it will make their monsoons worse. And that’s very plausible, because the monsoon has a kind of push-me-pull-you character in that part of the world. So what happens then? I mean these are nuclear-armed states. We don’t have the beginning of a policy about how we should settle those disputes.
Paul Solman: So when I was a kid, I remember people talking about the inevitability of cloud seeding so that you would be able to make it rain when and where you wanted it. Is this like a hyper version of that problem?
David Keith: Yes. In the sense that there might be, in the monsoon case, a situation where if China gets it a little better, India gets a little worse. I don’t know if that’s true. It could be the other way around. The point is there’s reason to believe it might be true, and that’s the kind of stuff that makes politics really hard.
Paul Solman: Is your bottom line here to proceed with great trepidation when it comes to solar geoengineering?
David Keith: My most important bottom line is, ignorance is dangerous. We have used a prejudice against this technology for decades to block essentially any research. Even now, there is no federal research program of any significant scale on a technology that has the potential to cut many of the key risks of climate change by, say, more than half over the century. These are enormous benefits. The thing we need is knowledge.
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