TCS Daily


Operation Sunscreen

By Arnold Kling - November 2, 2006 12:00 AM

"Using the results from formal economic models, the Review estimates that if we don't act, the overall costs and risks of climate change will be equivalent to losing at least 5% of global GDP each year, now and forever. If a wider range of risks and impacts is taken into account, the estimates of damage could rise to 20% of GDP or more.

In contrast, the costs of action - reducing greenhouse gas emissions to avoid the worst impacts of climate change - can be limited to around 1% of global GDP each year."
-- Stern Review on the economics of climate change

While somewhat downplayed in the United States -- the Washington Post buried it on page 18 -- the review of the economics of climate change headed by former World Bank economist Nicholas Stern was well publicized in Europe. Government officials in the United Kingdom, for example, are using it as a guide for policy advocacy.

For this essay, I want to take as given the report's assessment of the cost of global warming. Also, I will take as given that the strategy of reducing emissions of carbon dioxide, which I call the de-industrialization strategy, would cost one percent of global GDP each year. I want to suggest exploring an alternative strategy for fighting global warming, which I call the climate engineering strategy.

Climate engineering, or what I call Operation Sunscreen, would mean trying to alter the heat absorption properties of the atmosphere. The goal might be to reduce average temperatures by, say, 2 degrees centigrade.

I have no idea how to reduce heat absorption, but one can imagine a number of possible approaches to climate engineering: putting reflectors out into space; using some physical or chemical process to "wash" carbon out of the atmosphere; or coming up with a way to reduce concentrations of water vapor (the most abundant greenhouse gas) in the atmosphere.

One is a Big Number

When the Stern Review says that the cost of the de-industrialization strategy "can be limited to around 1% of global GDP each year," that makes the cost seem small. The number 1, after all, is a low number.

However, when the cost of de-industrialization is converted to dollars, the number no longer seems trivial. According to World Bank data, total world GDP in 2005 was over $40 trillion dollars. One percent of that would be over $400 billion dollars. What Stern is saying is that we should forego over $400 billion a year to forestall global warming. Of course, his Review estimates that the cost of global warming would be far higher. Again, for the purpose of this essay I am not questioning that. Instead, I want to suggest that at a price of $400 billion a year, it is worth investigating the possibility of alternatives to the de-industrialization strategy.

For example, imagine that Operation Sunscreen could be deployed for a one-time cost of $50 billion, with annual maintenance costs of $2 billion. That would clearly be far less costly to the world than a de-industrialization strategy that costs $400 billion per year.

Another potential advantage of Operation Sunscreen is that we might produce more reliable management of global temperatures. For example, it would be rather a shame to toss away $400 billion dollars a year using the de-industrialization strategy and then discover "Oops, the cause of global warming wasn't carbon-dioxide emissions after all. It must have been something else, because temperatures are still rising, even though we reduced emissions to levels that we thought would stabilize global temperature." Instead, climate engineering could reduce global average temperature regardless of whether global warming is caused by carbon-dioxide emissions or not.

Feasibility Study

I readily concede that I have no idea whether Operation Sunscreen can be carried out or what it might cost. What I would propose at this stage is that the National Science Foundation undertake a feasibility study concerning the climate engineering strategy. This feasibility study would examine various approaches in order to assess their costs, benefits, and risks.

I also will concede that I am not entirely comfortable putting the world's climate in the hands of scientists who attempt to engage in climate engineering. However, that discomfort is nothing compared with my fear of putting our future in the hands of international bureaucrats who are eager to embrace de-industrialization and to engineer a reduction of world GDP of $400 billion a year.

Arnold Kling is author of Learning Economics.


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58 Comments

Great point.
This vaguely reminds me of five years ago when I was working for a time as an engineer at a soon to fail dot com. As things began to go sour, we would have a few MBAs in to sit around the table and tell us their MBA crap while the leaks in the ship continued to grow and the ship began taking on water. I promised myself the day after I quit that before I became another worker bee in another silly startup, I would get an MBA from a good school so I could pull mine out in such situations and tell those people to cut the BS because we had a ship to save.

Arnold... I think if you wanted to save the world, you'd spend 2.5 years and get a Ph.D. in climate science so you could sort through the BS, bring your econ training to bear on identifying reasonably solutions, and then write 100 great essays about it. Having seen Ronald Bailey's "conversion" a little over a year ago, I'm unconvinced... He's really a journalist by trade with an interest in science, not a scientist who can think and write.

Ronald Bailey switches sides:
http://www.reason.com/news/show/34079.html

Space Reflectors
Space reflectors wouldn't be an especially feasible solution. The problem isn't so much the scale of the project, which admittedly would be extreme. The problems:

1. If you provide coverage for any less than the entire Earth, then you change solar energy distribution

2. All that energy that is being prevented from hitting the Earth? It has to go somewhere. Either the sunlight is going to push on the reflector ( thus changing its orbital position ), or be absorbed by the reflector ( heating it up ).

That second one, in particular, pretty much kills the viability of orbital solar reflectors/filters.

Better Economic Advice: Adapt
Since you are talking about sunscreen you have understood the main culprit behind any global warming, the sun.

Do you know why the sun fluctuates? What impact do gamma ray bursts have on the atmosphere?

Don't know? Why do you think any method to screen the sun will have the intended consequence?

The Federal Reserve consistently misses the mark on interest rates weakening the economy.

If any sunscreen proposal misses the mark, better make plans to move south.

The best econnomic advice is to plan for the worst and hope for the best. And if the best happens, keep the savings for the worst.

A reflector....reflects.
If a mirror reflects 97% it must absorb and emit 3%. That which is not reflected onto the earth can be reflected into space.

And we know how to keep satellites in an orbit.

What is 13W/m2 *.03? A mirror might absorb .4 W/m2 and methods can be employed to dissipate that heat.

It's already "engineering"
Great suggestion, and very common sensical. Too often a conversation will crash on the rocks of the supposed CAUSES of global warming. My answer to that is always the same: Who cares?

When Australian aboriginals began annually burning their landscape 50 - 60,000 years ago, they were doing engineering. When someone first had the idea to breed a better goat, or produce better yielding wheat by combining characteristics of different individuals, they were suddenly practising genetic engineeering. And when industrial-sized combustion processes began to vent greenhouse gases into the air in the 19th century, the largest engineering project the world had ever seen was underway. (That it's been a kind of an ongoing experiment is indiputable.)

So how comfortable am I that climate engineering has been in the hands of industrialists ever since then?

There are some very fine scientists and engineers who are working hard at the challenge of carbon sequestration. It will definitely take "bureaucrats" to fund them, as they seek ways to exploit the world's various carbon sinks. My favorite strategy is one that hopes to convert atmospheric carbon into a solid. Others would attempt to pump carbon to the bottom of the ocean.

I noticed that Al Gore, eager to embrace de-industrialization, devoted exactly half a sentence to the matter of carbon sequestration in his film. I found that very disappointing, and very telling.

http://en.wikipedia.org/wiki/Carbon_sequestration

Your government hard at work
Here's the US Department of Energy's address for our "Carbon Sequestration Project Portfolio", for 2006. You'll find some really novel ideas in it.

http://www.netl.doe.gov/publications/carbon_seq/project%20portfolio/project_portfolio2/table_contents.pdf

Highlights from last year's portfolio:

- The Regional Carbon Sequestration Partnerships have progressed to a validation phase in which they will conduct 25 field tests involving the injection of CO2 into underground formations where it will be stored and monitored.

- Pilot-scale tests and modeling of amine-based CO2 capture have shown that operating an amine stripper at vacuum can reduce energy use 5-10 percent per unit of CO2 captured.

- Novel metal organic frameworks have shown significant potential as CO2 sorbents.

Energy Security, not Global Warming, is the Contemporary Challenge
There is no doubt in my mind that Climate Engineering will be developed and deployed in the 21rst century. However, such a project is likely similar in scope to developing a fusion reactor…which means time consuming and very expensive.

In the near term (between now and the Fusion/Climate Engineering era), there is a strategy that would reduce CO2 concentrations in the atmosphere…I will name it Energy Diversification. Military and economic SECURITY considerations are quite persuasive that gasoline be reduced from current levels of 95%+ to less than 30% of total automotive fuel within the next 20 years. When gasoline consumption is reduced, CO2 emissions will also decline. Fuels such as diesel, ethanol and electricity can be substituted for / partnered with gasoline. A plug-in flex-fuel (PIFF) vehicle running on electricity partnered with diesel/ethanol would use little or no gasoline. These types of vehicles can/are being designed and built today. Oil, gas and coal resources are variably insecure in the short run and definitively finite in the long term. It is simply smart business for both energy producers and consumers to diversify energy sources.

Tyrannical government action is NOT required to achieve results. If the Federal Government supports energy research, education and free markets (in other words, follows the US Constitution), the producers and consumers of energy will make the correct choices in their own self-interest.

At last
"For this essay, I want to take as given the report's assessment of the cost of global warming."

Once you believe global warming will be expensive, you can start comparing the costs of various cures. Many scientists have suggested that the cost of a "clean up" strategy (removing CO2 from the air, increasing albedo using mirrors, etc.) is less than the cost of a strategy that reduces greenhouse gas emmissions.

reflectors
Even when photons are absorbed, they still transfer their momentum to the object doing the absorbing.

By changing the angle of the reflector as it orbits the earth you can balance out the momentums created by reflecting photons. The angle changing can be done with gyroscopes which can be powered by solar cells.

try reading what is written, not what you want to see.
The author did not accept the notion that global warming is real and will be expensive.

In fact, there is no evidence to support such a belief.

http://www.chooseclimate.org/cleng/cleng.html
This link http://www.chooseclimate.org/cleng/cleng.html shows a whole bunch of climate change suggestions.

My favourite is 2.2.2 putting up planeloads of dust into the stratosphere. Partly because it would probably cost less than Kyoto, not the $800 million a day enforcement costs, but the flying of 26,000 assorted bureaucrats to the city to attend the conference, and partly because if it turns out to be counterproductive it can be stopped pretty quickly.

Minor Disagreement
When someone first had the idea to breed a better goat, or produce better yielding wheat by combining characteristics of different individuals, they were suddenly practising genetic engineeering.

Wait a minute? If I recall correctly, selective breeding only favors existing genetic traits. Genetic engineering introduces new genetic instructions that didn't previously exist.

I'm no scientist but as far as I know the difference would be best illustrated by the little science project that produced a mouse with a human ear on its back-that could never be duplicated by selective breeding.

What happens when a big volcano erupts?
?

Your Ignoring a Couple Things
1. Light carries momentum. Any light that is either absorbed by, or reflected off of, the array transmits momentum into the reflector array. For a reflector large enough to matter, this would be a nontrivial accelerating force. Especially since its a nice evenly distributed force, whereas rocket burns to keep it in orbit would be localized to where the rockets are. . . requiring additional complexity and mass, since you'd need alot of them, spread out over the reflector.

2. Heat dissipation is not a simple matter in space. Only radiation works as a means, and for radiation to work, you need radiators. Given your talking about absorbing a nontrivial amount of the energy delivered to the Earth by the sun. . . they need to be damn good radiators. This also adds complexity and mass to the entire reflector project.

Between these two problems, both exacerbated by the fact that the only feasible way any time soon to build something this big is if nearly all of it is a thin reflective film with almost no mass, don't count on this working anytime in your lifetime, if ever. Adding additional particulates to the atmosphere, or screwing with cloud formation, both are simple next to this.

Your going to be changing the angle. . .
. . .of something at least a sizeable fraction, if not equal in size to, the cross sectional area of the Earth? Good luck. I hope you manage to invent a material with unprecedent rigidity, otherwise trying to do this will just tear it into pieces.

Never mind the fact that no matter the relative angle of the reflector, the direction of the momentum gained is always going to include a component in the "away from the sun" direction.

Don't Forget the Lawyers
"Therefore, I suggest a two-step process:

1. Until there is scientific proof that a weather modification technique is both safe and effective, every attempt to use that technique should be part of a scientific research program that is carefully designed, conducted, and analyzed. It is essential that every such program be reported in archival professional journals and books, to share knowledge and to prevent repetition of past mistakes, as well as to provide a basis for public recognition of a technique as safe and effective.

2. After there is scientific proof that a weather modification technique is both safe and effective, then that technique may be used in operational programs. However, it would still be a good policy to have a government agency review and approve each operational plan, before granting a permit for operational weather modification."

http://www.rbs2.com/w2.htm

The Same Thing That Always Happens
Average global temperature drops a bit for a couple years.

Maybe we should try triggering eruptions if global warming proves too problematic. . .

planes
I remember reading a suggestion several years ago that the FAA change the altitude at which planes fly every day so as to maximize the number of contrails.

you don't change the angle of the entire thing
You can also have your reflector made up of many individually mounted mirrors. Each mirror can be pivoted, while the entire structure remains still.

Away from the sun doesn't matter, away from the earth does.
At least when you are figuring out how reflected light affects a device in earth orbit.

For example, imagine a divice that is oriented so that it is perpendicular to the sun's rays. It also orbits the earth in such a way that it's orbit is parallel to the plane formed by earth/sun axis. When it is orbiting towards the sun, the photons slow it down. When it is orbiting away from the sun, the photons speed it up. These two components cancel out. When it is between the earth and the sun, the photons neither speed it up, nor slow it down, but they push it towards the earth. When it is behind the earth, the photons don't hit it, so it has no affect. The result of such an orbit is that over time, the orbit will grow more elliptical with perehilon gradually getting closer to the earth.

This can be changed by instead of keeping the mirror facing the sun all of the time, angle the mirrors when the satellite is between the earth and the sun so that the photons are reflected not straight back towards the sun, but partially in a direction opposite the orbital direction. The result is an acceleration in orbital velocity at the same time the satellite is being pushed towards the earth. The actual angle is based on math too complicated to do in my head. At another time, perhaps as the satellite is approaching and leaving the earth's shadow, the mirrors need to be angled so that the reflected photons cancel out the extra momentum gained while passing in front of the earth.

The math is complicated, but getting the orbit to be stable is doable.

mice with human ears
Had nothing to do with genetic manipulation. Aspecial material (I don't remember what it was) was formed into the shape of a human ear and surgically placed under the mouses skin. The mouses body then formed cartelige on the material. When enough cartelidge had formed, the ear was removed and sterilized (Cartelidge itself is not allergenic), and stored. The hope was that the sterilized ear could be used for transplants.

I thought you were going to say we could orbit the lawyers to use as sun screens.
rats.

So the corn crop fails for a few years, big deal?
!

That Introduces Even Worse Problems
Specifically, the fact that the amount of sunlight being blocked is variable with time *and* over the surface of the Earth. Whats more, introducing individual pivot motors for pieces of the reflector would, again, up the mass and complexity well beyond anything reasonably achievable.

Think big, basically. To make a meaningful difference, you'd need something thousands of square kilometers in size, at a minimum. Just unwrapping a mylar film that big in orbit is a task several orders of magnitude greater than anything currently ever attempted. Trying to assemble what amounts to a space station that big? If we had the tech to do something that big, climate change would be vaguely irrelevant.

Given that eruptions that size have happened in my lifetime. . .
. . .somehow, I'm not overly worried.

Orbitting the Lawyers First Would Be Necessary for All These Ideas
Any attempted climate engineering would draw lawsuits like honey draws flies. Its NIMBY, except with the entire world's backyard.

( Doesn't that mean we should be able to sue over the entirely predictable horrible economic consequences of obeyying Kyoto? Hmm. . . )

I never said I was a proponent of the idea.
I was just pointing out that one of your objections was over comeable.

As to the amount of sunlight being blocked being variable. So what? Since the variation is knowable in advance, just put that variation into your equations when designing the system.

Question
The earth presents about 25,000 square miles of surface to the sun. Suppose we could achieve the desired amount of reflection by superposing a disc of 2500 square miles in synchronous orbit in front of the earth.

Any ideas on how to construct a disc of that size? Obviously it would have to be built in place, probably out of superthin Mylar film. But to me it doesn't seem feasible at all.

For one thing, we've never sent anything into solar synchronous orbit. Nor have we sent anything into an earth orbit that is stationary relative to the sun's position-- i.e. that hangs at perpetual high noon over the earth.

How would you approach those problems?

Heh, What Equation?
While variance in total solar energy input is something known and dealt with in climate modelling, I don't think anyone has even touched the idea of variable energy exposure outside the atmosphere. Closest I can think is clouds effecting solar energy retention, and other albedo variants. . . except here, the energy is never getting to the Earth in the first place.

Actually radiative cooling works quite well in space
The temperature of a planar black body at the Earth's orbit is only 394 Kelvin or about 120 C (if I did my sums correctly). Any increase in albedo (reflection) above zero and the temperature goes down. That's because the black body is radiating heat into space which has a temperature of about 3 Kelvin, or barely above absolute zero, and there's no atmosphere to complicate things. There are no radiators on the solar panels for the Hubble telescope or the International Space Station, for example, and they work pretty well. Removing heat from the body of the telescope and the station itself is another matter, but that's irrelevant to a sun shield. You seem to be confusing radiative cooling with something like a car radiator which is actually a device to transfer heat from the engine coolant to the air.

Add some solar panels to the shield to power small ion engines and the light pressure problem goes away. This doesn't mean that I think a sun shield is a practical solution, just that your arguments against it are not very good.

Clouds go away!
IMO "screwing with cloud formation" might not be such a good idea.

For one thing, we don't get enough rain as it is. It is pretty widely recognized that one of the main limits to growth is going to be the availability of enough clean, fresh water to irrigate the crops that we will need to feed nine billion expected earth passengers. Plus, of course, the needs of lawns and golf courses. I think if anything we're going to want to see if we can screw with cloud formation the other way, to see whether we can't bring rain to the arid regions we'll be needing for cropland.

And for another thing, cloud cover only reflects light off to space during the day time, when the sun is out. During the other twelve hours, clouds insulate the earth with their heat retaining blanket.

Try to dissipate them? Let's not do that.

Particulates, on the other hand, are an approach worth studying. It already appears that our rate of heating has been greatly attenuated by manmade aerosols that absorb solar energy. We should see what the consequences are of polluting the skies even more than we are now.

What to do?
The problem with learning to adapt is the adverse nature of the changes in a runaway greenhouse earth. Arnold in the article puts these costs at 20% or more of global GDP each and every year. Which seems about right. For one thing you'd have to start moving all the world's coastal cities inland. Real estate markets would be in for a bit of a jolt.

But the big problem coming down the pike with that approach is that every nation on earth is going to want to move somewhere else. It will either be too hot, too dry, too wet or some other problem where they are. And they'll be feeding many more mouths than currently exist. So anticipate global wars of resource sequestration, as people set out to conquer a more viable territory in which to live.

One problem that may drive the gravity of the matter home for you is that the concept of private property in a radically changing earth is going to be in for some serious, unavoidable revision.

For me a better course would be to see whether we can't come up with schemes to mitigate global emissions while at the same time expanding energy production. A tall order, but something that will be on center stage anyway in the world of tomorrow.

Never heard of SOHO?
"For one thing, we've never sent anything into solar synchronous orbit. Nor have we sent anything into an earth orbit that is stationary relative to the sun's position-- i.e. that hangs at perpetual high noon over the earth."

Wrong again Roy. The solar high noon synchronous orbit point in question is known as L1 (for Lagrange point 1) and is currently occupied by the Solar and Heliospheric Observatory Satellite. See here: http://map.gsfc.nasa.gov/m_mm/ob_techorbit1.html

The L1 (and L2) points are not stable, unlike L4 and L5 the proposed locations of space habitats, on a time scale of 23 days and SOHO requires course corrections to maintain position. The L1 point is also rather a long way away from Earth so a screen built there would have to be VERY large. So you are correct that it isn't practical, just wrong about that particular reason why.

Corrected
As I remembered it, they played with DNA. Must be gettin' old, used to be able to recall such detail with perfect accuracy.

Last I heard, contrails caused warming
Please correct me if you can cite a counter argument.

That's what sovereign immunity is for.
However, any program like this should be based on a model that can incorporate global warming here, duplicating the historical data that we have, and account for the fact that the Martian ice caps are melting also. Hasn't been done yet.

Your not too worried about farmers going out of business or
starving indigent farmers in third world countries?

roy loves to trot out disproven canards
The claim that aerosols have attenuated the expected heating from CO2 has been shot down so many times it's getting motion sickness.

How the heck is an additional 0.1C degrees heat going to cost us 20% of GDP?
That's the most we are likely to see from another doubling of CO2. Not that CO2 is going to double anyway.

It may have been something to do with tuning down the mouses immune reaction.
...

Frankly, No
If it didn't happen when Pinatuba(sic?) blew, its not going to happen sans an asteroid.

And third world farmers have vastly more problematic reasons to starve, namely, local politics.

The Hubble Isn't Designed to Absorb a Significant Fraction of Incoming Solar Radiation
And unless its a perfect reflector, thats exactly what this project would end up doing.

( I'm also skeptical of your claim about the space station, as the shuttle most definitely does have radiators. Will have to check )

In addition, you act like adding solar panels and ion engines to the orbital reflector is a trivial undertaking. Remember, any engine, even ion engines, will exert an uneven force on the reflector material, greatest around the points where the engine is attached. Thus, the material has to be strong enough to withstand this uneven force. This directly contradicts the desire that the reflector be as lightweight as even vaguely possible, in order to keep the construction difficulties within the vaguely possible.

I didn't say it was a good idea; I said it'd be easier than trying to build a meaningful reflector s
(nt)

cut and paste
I did not make up the line. I copied it by cut and paste. I was surprised to read it. What he was accepting was: "Using the results from formal economic models, the Review estimates that if we don't act, the overall costs and risks of climate change will be equivalent to losing at least 5% of global GDP each year, now and forever." (again by cut and paste)

If you have a beef, it's with Arnold Kling, not me.

The plan of dumping sulfur
From what I read, dumping sulphur into the atm would have at least a two year affect.

The day after sulfur is dumped, a large volcano erupts and the sun dims. Ice Age?

I was talking about the solar panels, not the station itself.
Solar panels are a much better analogy to a sun shield.

The station and the Hubble are also covered with highly reflective gold coated foil, IIRC. And I'm sure they have radiators, which work quite effectively in vacuum in the shade. Temperature in the shade of 3 K remember? Radiated power = 0.0000000567*(temperature in degrees Kelvin to the fourth power) or about 450 watts/sq. m. at 298 K or 25 C. Radiators don't have to be very big, do they. That's not corrected for the Cosmic Microwave background, so it's actually slightly less than that, but not much.

Besides, if you look at my response to roy

http://www.tcsdaily.com/discussionForum.aspx?fldIdTopic=8728&fldIdMsg=49031

I really don't think a sun shield is even close to practical. Look how far away L1 is and how big a screen would have to be at that distance to reduce the solar irradiance by even a few tenths of a percent.

(sarcasm on) As far as stiffness, you could build the film supports from the same magical carbon nanotubes that you use to build a space elevator. (sarcasm off)

my beef is with your inability to read what you cut and paste.
It is quite clear that he is not accepting the number as true, he is just willing to use it as an absurd worst case, which still proves his point.

I didn't do my solar panel sums correctly
I forgot about the area of the back side. The black body temperature of a solar panel is actually 332 K or about 60 C. A lot of CPU's run at about that temperature.

could be embarassing
What would happen though if it turns out the the present slight GW is actually caused by something like solar flares, or the earth's uneven tilting, etc? Won't it be hugely humiliating for the people who thought it was human caused? These people might lose some precious self-esteem and not be able to figure out all the forms for their cushy research grants.

Still Not a Very Good Comparison
Functional solar panels are almost certainly a good deal more massive, physically, than any viable material for building a multithousand square mile filter. That means greater heat capacity than a thin plastic film. And all that needs to happen to cause problems is for the equilibrium temperature to be great enough to start causing breakdown in the filter. . .

Only If. . .
. . .you consider a two degree, rather than one degree, average temp change an "ice age."

Odd, that people have so much concern about vaguely possible threats, like volcanic eruptions disrupting a climate engineering effort. . .

. . .and yet no concern about the absolutely certain threat of trying to follow Kyoto.

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