I was reading (full disclosure: I read it in Superfreakonomics) about a research firm in Washington which proposed pumping SO2 into the upper atmosphere to counter global warming. As an aside, when the proposal was mentioned to Al Gore, he stated that he thought it was “nuts”, although the book didn’t state his reasons for thinking so. On the face of it, it does seem nuts, but is it? If so, why? In the lower atmosphere, it definitely would be, but that is not what is being proposed.
There’s not really a compelling reason to not research everything, because that is how you maximize technological progress. From everything I’ve read large scale geoengineering as it stands right now is a long way from “prime time”, and if/when it gets to prime time it will open up very interesting questions.
For example, Russia might decide it is beneficial for temperatures to be X, while the United States thinks it is beneficial for temperatures to be Y.
When we’re talking about having true and controllable “temperature changing” ability we’re talking probably after all of us are dead, but it’s somewhere in between “reasonable speculation/science fiction” and not on the “science fantasy” end of things.
The problem is that the environment has a lot of inertia, so it’s very hard to test things out without just going ahead and pumping out a metric shit-ton of whatever. At that point, if things don’t work out well, it’s going to be very difficult to adjust. So, until we have a damn good idea of just what exactly is going to happen (and when you’re talking about the atmosphere, that’s a whole lotta variables to consider), it’s probably best not to try anything radical.
Well, I wasn’t really referring to climate engineering in general, but rather to the specific proposal mentioned in the book. The idea is based on the global cooling effect that the eruption of Mt. Pinatubo had. The proposal states that pumping SO2 at a rate of merely 33gal/minute at high latitudes could effectively counter global warming and would be something that could be throttled. I don’t have the book in front of me, so if I have the details wrong, please feel free to correct them.
I’m no expert but everything I’ve read suggests it would be rather straightforward to cool the Earth with such a “sunscreen.” Moreover I suspect it will be done 25 years from now, or whenever decision makers agree that heating has become intolerable. (Having passenger jets discharge an appropriate material every trip has been suggested as a simple approach.)
The mystery is not whether the Earth could be cooled (with aerosols or whatever), but why this simple fact has barely entered the debate! AGW alarmists don’t want to talk about it – it would reduce alarm. AGW deniers don’t want to talk about it – one of their premises is that mankind is too puny to affect climate!
An important question, obviously, is whether such cooling would be a good idea. It would not solve the important problem of rising ocean acidity. Another issue, which I’ve not seen mentioned, is that I think the result of combining greenhouse and sunscreen effects to keep temperatures at a desired level would change the spectrum of sunlight – more infra-red (and red?) and less ultra-violet (and violet?). No idea how big that change would be, but I think it’s undesirable.
Upthread someone posted two links, but neither seemed to address the technical questions.
septimus, those links were intended to address the general question of whether Levitt and Dubner had much clue what they were talking about in the book. (The general opinion among actual scientists is, no.)
Their SO2 scheme seems nutty to me because atmospheric sulfur dioxide is what causes acid rain. Even if the plan “solved” global warming, reversing all the progress we’ve made on acid rain since that problem was identified in the '70s, and worse, doesn’t seem like a good trade.
Yeah, I think this scheme is nutty too, but to be fair, proponents of said scheme want to release comparatively small quantities of SO[sub]2[/sub] and only in the upper atmosphere where they will not contribute to acid rain.
I think this is being talked about a great deal. It’s been the subject of articles in the journals Nature and Science and there are at least two books out on the subject including Hack The Planet by Eli Kintisch. Even deniers get in on the action by using it to wave off the dangers of global warming as something that could easily be fixed (if it was real, which of course they don’t accept.)
They don’t stay there. The climate effects of volcanic eruptions are transient - even Pinatubo only resulted in 2-3 years of cooling. The particulates in the upper atmosphere reflect some sunlight (it’s not the chemical composition of the aerosols as much as they fact that there’s anything there in the first place), reducing the amount of radiation that reaches the earth’s surface… for a while. Then, because even tiny, tiny particles are still heavier than air, they settle out.
If you wanted to make the sunscreen that septimus mentioned, you’d have to continually inject aerosols into the upper atmosphere, and they’d be continually falling to earth. It might result in cooler temperatures (as long as you kept it up), but it would increase the rate of ocean acidification and it wouldn’t do anything about the rising concentrations of CO[sub]2[/sub]. SO[sub]2[/sub] also acts as a catalyst for a number of ozone-depleting reactions.
Personally, I have no particular love for the SO2 idea, but I don’t think it’s likely that global CO2 emissions will plateau until at least 50-100 years from now. The power needs of the planet are going to continue to grow. It would take 20-30 years just for the US to go Nuclear Power and then another 10-20 years to take all our coal plants off-line. In the meantime, as Africa, South America, etc. start to have power needs as high as the modern US, the US and Europe will likely continue to do their best to prevent them from having access to Nuclear materials. Coal power will be a cheap and endless supply of electricity based on tried, reliable, and cheap technology. They might start to move over to Nuclear after only a decade or two, but again we’re talking about 50-100 years from now to that point.
Anyone who actually cares about solving global warming should pay attention to climate engineering solutions. Emission reductions aren’t going to happen until the technology is equivalent in both capability and price as what we already have and even then the move will be slow. If the critical point for when temperatures need to start to go down is between now and 20 years from now, climate engineering is going to be the only way to affect that.
It should be pointed out that there is, in fact, one climate engineering project that we know we’re capable of, and which we know would have exactly the desired effect, and which is extremely well-understood. That method is to reduce our emissions of CO[sub]2[/sub]
I don’t think Levitt claims expertise in physical science. Debate should focus on the views of more informed proponents.
If a “sunscreen” were adopted, it wouldn’t involve pollutants injected into the troposphere. It would involve specially engineered non-polluting materials (to maximize sunscreening) injected into stratosphere. (I’m not necessarily a proponent; I just think debate should focus on best practice, not a “strawman”.)
There are some expert physicists in this thread. I hope they’ll do some back-of-the-envelope estimates. One reason my intuition tells me the redder spectrum would be undesirable is that the changed spectrum would be higher entropy and thus “less valuable.” (I changed “sunlight” to the less misleading “daylight” in this edit.)
(The strawman’s fallacy of debating one’s less informed opponents seems all-too common. One sees it in American politics, where rationalists single out the stupidest right-wing ideas for ridicule, while right-wing protests (“b…b…but we did have a constructive thought back in 1986”) go ignored. )
There are lots of engineering concepts being looked at. Painting roofs white, putting reflective coating on glaciers, pumping SO2 into the atmosphere, putting more clouds over the ocean, putting iron in the oceans, etc.
A major concern is the moral hazard of doing that, where people feel instead of just shifting to a clean energy economy we can just continue dumping hundreds of billions of tons of pollutants into the atmosphere and just dump different products in to counteract the old ones.
Plus other issues will not be affected. The oceans will still acidify due to CO2 for example. Plus I have heard that SO2 can change rain patterns and was a factor in massive droughts in the 80s that caused famines in Africa.
As a stopgap solution that’ll buy us 10-20 extra years to implement large scale energy policy changes, it wouldn’t be a bad idea. It could save a lot of money in property damage if it stops flooding.
I have always wondered why we do not try to turn the california desert into a productive agricultural area (I am talking about the area east of Los Angeles 9the Salton Sea Area).
Basically, we would use the flood waters from the All-American Canal to restore the Salton Sea (which is now drying up), and create several other large lakes in the basin. We would also flood other low lying areas, and create massive swamp areas-which would be colonized by mangrove trees. The huge evaporation from these lakes and swamps would make the local climate wetter, and we could then plant trees and grasses-a sort of 'Terraforming".
As the area continued to get wetter, eventually we could farm the place, and make it greener.
Of course, the main reason why the Salton Sea Basin is so dry, is that the Pacific Ocean off the California coast is so cold-there isn’t enough evaporation to form substantial rain clouds.
This could be remedied by another of my pet projects-the diversion of the cold North Pacific current (which flows down the California coast).
My plan is to divert this current by placing massive curtains, suspended from chains of tethered floats, anchored off the Farallon Islands. This would shunt the cold southward currents to the west, and allow warmer waters from the south to replace the colder water.
All of this would make extreme Southern California wetter and greener.
As Spark’s link points out, you’re countering reduced outgoing heat energy by reducing incoming solar energy. This means that just even maintaining the same temperature would reduce the effectiveness of solar power and plants.
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