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What's the Cheapest Way to Reduce Global Temparture By 3°C?

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This is a question I asked Robin at today's lunch. Soon afterwards, I learned that AEI just had the first of a series of conferences on this topic, known as "geoengineering":

For more than twenty years, policymakers have struggled to find ways to reduce greenhouse gas emissions enough to stop global climate change. Congress is likely to enact federal climate legislation in 2009, but many scientists fear that emissions reductions may not occur quickly enough to prevent significant warming. Some scientists also fear that potentially catastrophic effects, such as the melting of the polar ice caps, could happen unexpectedly quickly. If warming proves to be uncontrollable and dangerous, what could we do?

A growing number of climate scientists believe that there may be only one possible answer to that question: change features of the earth's environment in ways that would offset the warming effect of greenhouse gases, a concept known as "geoengineering" (or "climate engineering"). The most plausible way of doing this would be to use very fine particles in (or above) the stratosphere to block a small fraction (roughly 2 percent) of sunlight. While geoengineering science is in its infancy, most scientists who have studied the idea believe it is likely to be feasible and cost-effective.

My knowledge of natural science is minimal. Is this a pipe dream - or a practical solution that the man in the street is too dogmatic to consider?

HT: Lee Lane


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COMMENTS (38 to date)
Tim writes:

But won't that endanger us with the same "global cooling" we were concerned with twenty-odd years ago?

Stephen W. Stanton writes:

This is not a pipe dream.

This is exactly what happens with large volcanoes. It would be realtively cheap to belch out soot and dust into the upper atmosphere.

The only catch involves the likely unintended consequences (e.g., acid rain) and the poitics of who gains/loses by these solutions. The impact of the particles will not be globally uniform. Some climates will improve, some will get worse, solar power will lose some capacity everywhere, and some folks will be living in the areas where the dust literally settles.

Jason writes:

Seeing as how global temperatures have been falling steadily for the past few years, I would recommend the cheapest way of reducing the global temperature would be to just wait. It appears to be decreasing without any kind of intervention on our part.

Matt writes:

The telescope lobby might be upset.

Gavin Andresen writes:

There was a good PBS Nova episode "Dimming the Sun" (see http://www.pbs.org/wgbh/nova/sun/ ) a while ago that speculated that all the soot China is spewing into the atmosphere (from burning coal) is holding down global warming increases.

And that as China gets richer and more environmentally conscious, global warming may accelerate (they'll put less soot into the atmosphere, which is good for the immediate health of their citizens but bad for global warming).

One interesting bit of evidence they showed was from the days after 9/11, when all commercial aircraft were grounded. That meant no jet contrails, which meant more sunlight reaching the ground, which raised the temperature a measurable amount.

... and that, of course, suggests that maybe making jets create bigger or longer-lasting contrails might be a way of fooling with surface temperature.

Paul writes:

I find all this talk about climate change silly. Unless we can answer the question of what the optimal climate is (and we can't), why are we talking about changing it, or preventing changes? And what on earth gives anybody the idea that we can fine tune the climate, when we don't even have a theory from which to work from? I swear, the world has gone mad.

fundamentalist writes:

I saw that NOVA episode. It also had a bit on the pollution over southern India that extends miles into the ocean. The temperature in the ocean under the pollution is about 10 degrees cooler than in the ocean without the pollution. So the answer is to pollute more!

Mark Wonsil writes:

Contrails cool the earth during the day but warm it during the night.

http://www.atmos.berkeley.edu/news/cohen_jul2002.article

Matt writes:

Legally, what is the Supreme Court's role?

In the conflict between the power to regulate and the protection of property rights, there has been no eminent domain, it is still private property.

Any civil suit should be treated on its merits.

The sooner the court acts, the most efficient the outcome, is my claim.

The cheapest way would be to wait for the effects of the sun's temperature dropping to take effect over the next several years. The last time the sun had this few sunspots, we entered what was known at the "Little Ice Age," which ended around 1900.

Dr. T writes:
What's the Cheapest Way to Reduce Global Temparture By 3°C?
Tying plastic bags over the heads of hot air-generating IPCC officers, environmentalists, politicians, and other who generate or condone anthropogenic global warming propaganda and lies. Even if their elimination doesn't cool the earth, it will raise the average IQ of mankind.
Chuck writes:

Funny how with the government we are all afeared of unintended consequences.

Then, when it comes to the environment, which day after day I'm told we don't understand well enough to say that anthropogenic global warming is real, we are 'too dogmatic' if we are afriad of mucking around with it?

Bob Knaus writes:

The costs of lowering the global temperature by 3 degrees C should include the costs of dealing with what Russia would consider an act of war.

Stratfor has mentioned this more than once in their weekly briefings, but you have to be a member to search for it in their archives. Their analysis does seem credible to me.

Michael Kolczynski writes:

At the risk of sounding like a typical global warming denier: why would we want to?

the theory of anthropogenic global warming revolves around calculations that require a rise in atmospheric carbon dioxide to set off an increase in atmospheric water vapor. While it is certainly the IPCCs stance that global mean surface temperatures will increase, it is actually, by their very own admission, unsettled.

In the IPCC report it specifically states that biological responses to an increase in carbon dioxide concentrations (i.e. trees and other plant life) are unknown. There have been many studies done on various plants that show that in an atmosphere of severely increased carbon dioxide concentrations photosynthesis increases greatly and is optimal at a higher temperature. These factors are not calculated in the projections that are used in the IPCC report. This is not a paranoid conspiracy theory, it is actually stated in the IPCC report.

Not only that, there has been very little additional research investigating the theory of anthropogenic global warming. Instead, the bulk of the research has been done taking it as a given that the increase of atmospheric carbon dioxide will increase atmospheric water vapor which will only result in more absorption of infrared light creating a rise in temperature. However that is still open for debate seeing as how water vapor is what forms clouds. Clouds reflect the sunlight prior to it reaching near surface and becoming infrared light. Cloud coverage reflecting light is linear, whereas increased carbon dioxide and increased water vapor in the atmosphere, absorbing more infrared light, is logarithmic. Therefore, in the still debatable realm of which will be greater cloud coverage or atmospheric water vapor concentration, clouds have an easier chance of repelling more sunlight than an increase in atmospheric water vapor does absorbing more infrared light.

So, if cloud coverage were to increase due to the increase in atmospheric carbon dioxide, thereby reducing the amount of sunlight that reaches Earth, why on earth would we want to take measures to do anything that could potentially be undoable in the short term.

I'm sure there are many things that can be done and some of them fairly inexpensive: such as communities taking an initiative to paint their houses lighter colors -- even white. Also there may be perhaps lighter colored tar that can be used for roads. And I'm sure we can put things in the atmosphere that have the effect of reflecting more sunlight. Some of these things are more reversible than others. But again I ask, why would we want to when the science is still young and there are still plenty of room for debate and anyone who says otherwise is simply not done research to find the lack of evidence that exists.

Here is a link to a research paper that covers a lot of issues concerning global warming and the general lack of supporting evidence. http://www.petitionproject.org/gwdatabase/GW_Article/GWReview_OISM600.pdf

Jim Glass writes:

Freeman Dyson recommends genetically engineered carbon-grabbing trees.

Of course, Dyson also proposed engineering trees to grow on comets to create oxygen so people could live in the hollowed-out inside. Compared to that, carbon-sucking trees here on earth are nothing.

Dyson made the tree proposal in the NY Review of Books reviewing Nordhaus's latest, which I do not find too comforting, gist here. Nordhaus's opinion on Al Gore ... "Just say NO!".

Jim Glass writes:

Premises:

1) American politicians are tax-phobic (all, not just Republicans) and are adopting cap-and-trade instead of a much more transparent carbon tax because (a) it saves them from having to say the word "tax": and (b) it is opaque so they can meddle in it for political gain (and thus undermine it.)

2) The European experience with cap-and-trade has been a fiasco resulting in increased emissions, for exactly the reasons above.

3) Nonetheless, cap-and-trade effectively is a TAX and to meet targets it will be a MASSIVE one, as per ...

4) The Warner-Lieberman C&T bill requires the U.S. to cut its CO2 emissions in 2050 to the amount they were in 1922. In 1922 the GDP was $730 billion (2007 dollars) for a population of 110 million, while in 2050 GDP (projecting 2.5% real growth) will be $33 trillion for a population of about 440 million.

You do the math to figure the kind of cut in CO2 emmisions that is in just 43 years, and the size of the effective tax increase needed to get it.

5) Given the record to date of the Europe and the US, I see no chance that the politicians will force everyone to achieve this.

6) Given the record of the rich world that could afford to take a hit, as per 5) above, I see **NO** chance that China and India are going to lock themselves in poverty for an extra couple generations over worry about Greenland ice.

Which leads me to ...

7) We had better hope for Dyson trees!

But, I'm not so disheartened about #7.

In literally the 100 years from the late 1860s to the late 1960s we Americans went from hunting whales in oar-driven longboats to get the whale-oil energy we needed for our reading lamps ... to using TV sets fed by nuclear power to watch astronauts play golf on the moon.

I think the concept of carbon-grabbing trees or bacteria or whatever is a lot more ho-hum today than the idea of real-time observation on earth of people playing golf on the moon would have been in the 1860s, so I deem it not implausible at all.

However: market failure. The commercial markets today provides more incentive to develop new acne medicine than carbon-grabbing plants.

So, I'd propose a prize fund -- a Dyson Prize. Say a billion dollars, or $5 billion, to reward targeted achievements in producing carbon-grabbing plants or whatever.

IMHO its not only by far our cheapest chance, it's probably our only one.

burger flipper writes:

What did Robin suggest?

Marty writes:

Actually, using one of Dyson's other engineering ideas, a Dyson sphere, none of this would be a problem. However, isn't a great deal of China's pollution in the form of Carbon-dioxide, which is actually what causes the greenhouse effect?

Peter St. Onge writes:

Assuming we're confident of a 3c rise, I'd think solar subsidies cheapest.

More dramatically, and expensively, how about paying russia & canada to plant quick-grow trees, but them down and stack the tree trunks on the tundra? That'd seem to precisely reverse burning fossil fuels, by sequestering co2.

The tree thing wouldn't be cheap, but does have the advantage of being unlikely to lead to unintended consequences/surprises from geoengineering.

Chuck E writes:

I'm surprised what a flip reception this idea is getting on this board.

For a long time, I've been shocked at the fact that these types of solutions haven't been taken more seriously. The idea of putting tiny particles in the air is very cheap, does not cause acid rain AFAIK (since they use silicon), can be stopped if we don't like it (since the stuff washes out of the air and then you have to "re-install" it), and would not put a "big cloud" over the earth.

We're talking about putting a tiny amount of silicon in the atmosphere over the poles, where warming is most "dangerous" anyway.

So why don't you hear this being discussed more? I think the GW activists aren't really interested in "solving" GW (i.e. they just want to stunt economic growth), and the GW "deniers" don't even want to consider the idea of cheaply solving a problem they don't think exists (rightly or wrongly).

Dr. T writes:

Chuck E:

You are not hearing about 'cheap' solutions to anthropogenic global warming because many of us don't believe it is happening or, if it is happening, don't believe that the detriments outweigh the benefits.

Tossing particles into the atmosphere to decrease solar heating is like putting asphalt patches on a road that has no potholes.

Barkley Rosser writes:

This is very possible and indeed very much under discussion. It will not be done anytime soon precisely because there are way too many possible unintended consequences, with many countries not necessarily supporting such an action (the point about Russia's views being very apropos).

The more serious analysts view it as a backup in case the more seriously pessimistic forecasts come true, as described in the post, and we get something like 6 degrees C increase or worse in the next half century to century. Then there might well become a global consensus to try something drastic and unpredictable like this.

Badger writes:

I live in Minnesota. I'll sue anyone who tries to make it even cooler in here...

Chuck E writes:

It will not be done anytime soon precisely because there are way too many possible unintended consequences, with many countries not necessarily supporting such an action (the point about Russia's views being very apropos).

Barkley- I understand the general concern about unintended consequences, but the silicon-in-the-atmosphere approach is reversible in the sense that the stuff washes out of the air within a short period. (Then you have to redo the operation.)

You refer to this approach as "drastic", but to me, dramatically reducing the amount of CO2-emitting activity around the world seems drastic. Heck, the current CO2-reduction proposals seems drastic to me, and a lot of them will hardly put a dent in the problem. (I saw a scientist on 60 Minutes claiming that if we completely stop emitting carbon right now, we'll still have climate problems!!)

The point about Russia is interesting, but I'm not sure I understand. Is the idea that Russia would want the world to be warmer? In any case, if actively reducing global temperatures would offend them, then they can't be too thrilled about cap-and-trade or other carbon-reduction measures, especially if it applies to them!

dearieme writes:

"What's the Cheapest Way to Reduce Global Temparture By 3°C?" Wait.

Richard Sprague writes:

Please, I beg you! Do not do this to my earth!

How can scientists possibly know, with confidence, all the unintended consequences and side effects of this kind of large-scale planetary engineering? The cure could easily be far, far worse than the disease.

Andrew Garland writes:

In 1975 the alarm was about global cooling. Amazing, yes? The story was that soot from automobile exhaust was drifting into the upper atmosphere and reflecting enough sunlight to cool the earth.

So, we already have an earth-changing solution to Global Warming. Drive more to save the Earth. (smile).

The Cooling World

Newsweek, April 28, 1975
There are ominous signs that the Earth’s weather patterns have begun to change dramatically and that these changes may portend a drastic decline in food production – with serious political implications for just about every nation on Earth. The drop in food output could begin quite soon, perhaps only 10 years from now.

... To scientists, these seemingly disparate incidents represent the advance signs of fundamental changes in the world’s weather. The central fact is that after three quarters of a century of extraordinarily mild conditions, the earth’s climate seems to be cooling down.
Chuck writes:

@Chuck E:

Barkley- I understand the general concern about unintended consequences, but the silicon-in-the-atmosphere approach is reversible in the sense that the stuff washes out of the air within a short period.

I think you should review the definition of uninteded consequences.

It's like my kids
me: "don't do that, you'll have an accident"
kids: "no I won't dad, I'm being careful"
me: "um, kids, an accident is what happens when you don't want it to, even when you are sometimes being careful"

The problem with global warming is a lot like the problem with leveraging investments. If nothing goes wrong, like you think they won't, then things are great instead of just good.

But if something goes wrong, you are ruined.

Ben Kalafut writes:

You're a little slow on the draw here; the stratospheric aerosol proposal has already been shelved, as it would be very harmful.

See Tilmes et al, Science 320:1201-1204.

Ocean fertilization is an interesting idea, as is using geoengineering to combat the ocean acidification which also results from increased atmospheric CO2. (This problem is a "big" one like global warming, but somehow it's under the radar of both the denialists and the popular press.)

Chuck E writes:

Ben:

Who said anything about sulfate aerosols?
I really don't see where you're getting this from.
Maybe you're referring to somebody else's comment.

Ben Kalafut writes:

The original post referred, implicitly, to sulfate aerosols:

A growing number of climate scientists believe that there may be only one possible answer to that question: change features of the earth's environment in ways that would offset the warming effect of greenhouse gases, a concept known as "geoengineering" (or "climate engineering"). The most plausible way of doing this would be to use very fine particles in (or above) the stratosphere to block a small fraction (roughly 2 percent) of sunlight. While geoengineering science is in its infancy, most scientists who have studied the idea believe it is likely to be feasible and cost-effective.

The word sulfate isn't mentioned here, but that's what the block-out-the-sun proposal entails. Some alternative would have to be found that does not enhance ozone depletion.

[Comment edited--Econlib Ed.]

Ben Kalafut writes:

Andrew Garland:

That a few journalists wrote pop pieces about global cooling does not mean that global cooling was considered a serious threat by climatologists in the 1970s.

Over on RealClimate, John Fleck and William Connoley put together a writeup that should end that silliness once and for all. Give it a look.

Chuck E writes:

Ben, the proposals I've seen don't use sulfate; they use silicon. Seems far more sane to me.

Ben Kalafut writes:

Chuck E:

Thanks for the heads-up on that. I've been following this and hadn't heard one. A quick google search turned up references to tetraethyl silicate in the blogosphere, but similar searching of the technical literature turned up absolutely nothing. Can you point me to something about this in a scientific journal?

I'm a biophysicist, which means that to chemists I'm an ignoramus; I'd like to know that whatever tetraethyl silicate becomes after being processed through a jet engine (the 'bloggers aren't sure) is not something that will catalyze the release of free radical chlorine from e.g. Freon. (Remember that ice crystals can do this!) The answer is nonobvious to me. We have good albeit purely empirical models for the effect cold sulfate aerosols have on potential for activated chlorine, but I can't find anything to that effect for aerosolized poly-SiO2, which is what, I'm guessing, the reaction product would be.

(Yes, yes, I'll GMOB!)

Boonton writes:

4) The Warner-Lieberman C&T bill requires the U.S. to cut its CO2 emissions in 2050 to the amount they were in 1922. In 1922 the GDP was $730 billion (2007 dollars) for a population of 110 million, while in 2050 GDP (projecting 2.5% real growth) will be $33 trillion for a population of about 440 million.

You do the math to figure the kind of cut in CO2 emmisions that is in just 43 years, and the size of the effective tax increase needed to get it.

Well here's an upper extreme. Suppose the only way to have the CO2 of 1922 is to have 1922's GDP. In other words, there is absolutely no way to save on CO2 emissions aside from simply doing without. In that case the 'tax' would be $33T - $730b = $32.270T

Here's a lower extreme. Suppose scientists discover that horses cause global warming and we need to reduce our horse population to 1922 levels. Well since we don't use horses anymore for transportation we probably already have fewer horses now than then...the 'tax' would be $33T-$33T= $0.

Between these two extremes is the truth which depends on whether or not we can generate GDP without releasing CO2. AS you point out, the future can turn out to be quite different than what we expect.

Does this mean the bill's a bad idea? Of course not. The analysis that is done above implies a single shot. You get one chance to make a policy and you're locked into it for the next 40+ years. That's not the truth, though.

If it turned out the 'tax' looks more like $32.27T we all know Congress would come under tremendous pressure to ease the C&T. If it lookes more like the $0 then all is great. It seems to me the sensible thing is start implementing C&T now, work out the bugs and such. If cutting CO2 turns out to be horribly expensive the gov't can 'ease' C&T by creating additional credits and selling them to the market. IF it turns out global warming causes us a lot of problems we can 'tighten' C&T by buying up credits from the market thereby reducing CO2. If this sounds familiar it is because we've been doing something like this for nearly 100 years, it's called the Federal Reserve.

Andrew Garland
In 1975 the alarm was about global cooling. Amazing, yes?

Amazing? No. You're talking about one Newsweek article in the 70's which even then was not clearly accepted by the scientific community. It's inaccurate to pretend that global warming is just another scientific fad that gets a lot of press attention and then fizzles out after the science is picked apart.

Chuck E
The point about Russia is interesting, but I'm not sure I understand. Is the idea that Russia would want the world to be warmer?

I think Russia would have two points:

1. Warming would help them since a lot of the country is frozen wasteland.

2. An average hids a lot. If the world's temp. went up 365 for one day we would all be dead yet the global average temp for the year would only rise by 1 degree. The particle idea may hold the average temp. level but could still cause chaos with some places getting really cold and others really hot. While it may be cheap to put the particles in the air it is anyone's guess what the costs of that policy would really be.

Chuck E writes:

Ben,

Here's one article that mentioned using silicon dioxide:

http://www.technologyreview.com/printer_friendly_article.aspx?id=18175

I'm no expert on this stuff, but it sounds very promising.

An excerpt:

He suggests suspension of tiny, harmless particles (sized at one-third of a micron) at about 80,000 feet up in the stratosphere. These particles could be composed of diatomaceous earth. "That's silicon dioxide, which is chemically inert, cheap as earth, and readily crushable to the size we want," Benford says. This could initially be tested, he says, over the Arctic, where warming is already considerable and where few human beings live. Arctic atmospheric circulation patterns would mostly confine the deployed particles around the North Pole. An initial experiment could occur north of 70 degrees latitude, over the Arctic Sea and outside national boundaries. "The fact that such an experiment is reversible is just as important as the fact that it's regional," says Benford.

Ben Kalafut writes:

Thanks for the pointer. It's very frustrating, that Mr. Benford is choosing not to discuss this in the peer-reviewed technical literature, instead making an "end-run" around the experts by going straight to the pop. press. I'd still like to know whether or not silicate surfaces would enhance production of free radical chlorine like (also chemically inert) ice, or cold sulfate.

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