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Tuesday, February 13, 2007 Cooling the PlanetIf we can't adequately reduce or sequester carbon emissions, are more-radical alternatives like orbital mirrors a solution to climate change? By Mark Williams
In the past two decades, various novel planet-cooling technologies have been proposed--improbable, monumental projects such as putting into orbit giant mirrors with thousand-kilometer diameters or clouds of trillions of wafer-thin, butterfly-light lenses. Until recently, such proposals have remained on the fringes of acceptable scientific speculation. Now, with the Intergovernmental Panel on Climate Change (IPCC) claiming in its report of February 3 that there's a 90 percent probability that the last half-century of global warming has been caused by humans, a milestone moment has apparently arrived. Four hours after the IPCC report's release, even the White House (historically extremely hostile to the idea of anthropogenic climate change) had unearthed a 2001 remark by President George W. Bush acknowledging that greenhouse-gas increases were largely created by humans. Consequently, while mainstream acceptance of climate change means that the battles over what humanity should do about it are just beginning, radical planet-cooling technological possibilities are receiving consideration alongside the standard proposals for capping, reducing, or sequestering carbon emissions. The notion of interposing a really big mirror between the Sun and Earth, which exploits the fact that our planet already reflects about 30 percent of incoming sunlight back into space by effectively increasing its reflectivity, dates back to the 1980s. Initially, such mirrors were suggested for cooling Venus as part of a theoretical future effort to terraform that planet. But in 1989, James Early of the Lawrence Livermore National Laboratory noted the harbingers of global warming and proposed deflecting a measure of sunlight with a "space shade" located at Lagrangian Point L1--an orbit 1.5 million kilometers up, where Earth's gravity and that of the Sun are balanced so an object can remain stationary relative to both bodies. How big a shield was Early thinking about? One 2,000 kilometers in diameter and about 10 microns thick, with a weight of about 100 megatons under Earth's gravity. Early's shield would have been either opaque or else transparent in the form of a Fresnel lens (the kind of lens used in lighthouses, in which the amount of material required is reduced from that needed in a conventional spherical lens because the lens is broken into concentric annular sections). Early estimated the cost at $1 to $10 trillion. As for assembling his giant mirror and placing it at L1, Early suggested using moon rock for the materials and a manufacturing plant on the lunar surface, then launching the components by a mass driver from the Moon to L1. Given how arduous even minor assembly work on the International Space Station's exterior has been, and given that NASA will almost certainly be unable to meet its schedule for returning to the Moon by 2020, such a megaconstruction doesn't seem immediately feasible. Last year Roger Angel, University of Arizona Regents Professor and the Steward Observatory Mirror Laboratory's director, offered another plan: to place in orbit at L1 a very great number of small, already assembled objects. Angel presented his concept to the National Academy of Sciences in April 2006, got a NASA grant to fund further research, and then published a detailed paper, "Feasibility of Cooling the Earth with a Cloud of Small Spacecraft near L1."
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Comments
akay on 02/13/2007 at 1:19 AM
4
Each square metre of desert receives sunlight equivalent to 1.5 barrels of oil annually, corresponding to a layer of oil 9 inch deep! The technology to tap this never ebbing well exists and is economically viable:
http://www.ases.org/climatechange/
Solar energy can be converted into electricity with 13 % efficiency by concentrating solar power plants (CSP) at a cost of $ 3-5 per Watt. CSP plants in California have been working reliably for 20 years.
http://www.trec-uk.org.uk/articles/gdn_061127_ber_27_15216508.pdf
With the amount of money spent in the “2nd oil war” (some $ 378 billion) one could trigger the construction of 300 GW of CSP plants, assuming $ 2 invested by private companies for each $ injected by the government. On a desert area of 7500 km2 (1.5% of the Great Basin) these would generate clean electricity equivalent to 3,000,000 barrels of oil per day, more than imported from the entire Persian Gulf region!
http://www.ez2c.de/ml/solar_land_area/
This would not only make us independent from Iraqi oil, but also save us and our children from climate disaster and radioactive waste as long as sun shines on earth. As a valuable by-product concentrated solar power can provide desalinated water to desert regions. Last, not least the construction of millions of mirrors from glass and steel would create countless jobs e.g. in the suffering automobile industry.
The fever of mother earth cannot be remedied by chilling, but only by eliminating its causes! Man has conquered space and landed on the moon. Now we need an Apollo Program for earth, to save our spaceship before its climatisation runs out of control. If America shows the way to go, other countries like China will follow. But who knows, maybe China will show US the way? They are already ahead in the photovoltaic module market:
http://www.renewableenergyaccess.com/rea/news/story?id=44457
http://www.trec-uk.org.uk/index.htm
http://www.energylan.sandia.gov/sunlab/index.html
http://www.solarpaces.org/News/Projects/USA.htm
deejay on 02/13/2007 at 1:52 AM
22
We've messed up the planet, and now instead of addressing the root cause, let's go and mess up space as well, by putting in the 'shadow'.
This will assist us in doubling the amount of carbon dioxide, so that we can simply suffocate!! JKust tink about it, this will definitely solve the problem since, as Mr Bush says, its just us humans who caused it.
mkogrady on 02/13/2007 at 11:50 AM
64
rluna on 02/15/2007 at 12:32 PM
8
dmorton on 02/13/2007 at 2:01 AM
1
What we really need is a microbe that turns the oil in oilfields into something much less usefull and accessible. Either that, or a sustained bombing program on energy infrastructure.
You tree-spikers out there better put your noggins to use spiking oilfields instead.
rluna on 02/15/2007 at 12:40 PM
8
Layne on 03/01/2007 at 3:08 AM
2
In this case, that means the evil consumers of oil and meat (which is causing more greenhouse gas effect than petrol).
(Sorry, I'm a newbie here, and not sure how serious or tongue-in-cheek the previous answers were. Mine's serious.)
Innovator-FS on 02/13/2007 at 5:05 AM
1
Why not cool the planet with water: abundantly available.
Use sunlight to desalinate water. Huge amounts to be pumped into the desert zones of the planet:
1. transfer sunlight into sweet water instead of reflection into the atmosphere
2. tap water that comes anyway available from melting icecaps and glaciers (reduce rising of the sealevel?)
3. develop plantlife in hughe areas to adsorb CO2
4. help the people to extend the agricultural areal
5. evaporation creates more clouds which reflect sunlight
All necessary technology is freely available, we can start immediately at large and small scale.
There are no still unknown risks to the planet and people when the system fails or hampers somewhere. (I rather not breath nanoparticles from the sky).
rluna on 02/15/2007 at 12:47 PM
8
gabrielg01 on 02/13/2007 at 5:58 AM
270
B) If you are still obsessed with mirrors, then you don't necessarily need a very large one. The further away you put it, the larger the shade will be - just make sure it is really a high quality mirror, so it reflects the energy and it does not get melted. And if you're still at it, then deflect that energy toward a cold planet, to aid in terraforming - Mars should do. Give Mars a 2nd Sun.
concerned1 on 02/13/2007 at 8:20 AM
2
Check this out: http://www.news.cornell.edu/stories/Feb06/AAAS.terra.preta.ssl.html
nekote on 02/13/2007 at 8:43 AM
98
A man-made non-radioactive version of the feared Nuclear winter?
Tiny particles in the atmosphere are usually called pollution.
And aren't very helpful when breathed into the lungs.
Any likely effects on LEO satellites or space launches / re-entries?
chipengineer on 02/18/2007 at 11:32 AM
2
>Any likely effects on LEO satellites or space launches / re-entries?
No effect on LEO satellites; the particles are not that high.
I'm not as sure about re-entries, but the particle density is very small. More certainly, no manned re-entries are even done at the proposed high latitudes.
mbmurphy777 on 02/13/2007 at 10:45 AM
14
Injecting sulfur based microparticles into the stratosphere
http://ergosphere.blogspot.com/2006/04/braking-before-environment-crash.html#links
http://www.springer-sbm.com/index.php?id=291&backPID=132&L=0&tx_tnc_news=2646
It'd be hard to get agreement on this type of intervention, but it is worth looking into.
Using sulfur based microparticulates delivered into the stratosphere could mitigate much of the expected warming, until there is a technological breakthrough in energy generation.
Of course, playing with a complex system like climate can be dangerous (which is why agreement on even a pilot study will be difficult).
abcarterjr on 02/13/2007 at 3:40 PM
45
influence Atlantic Hurricanes by heating the ocean
water in the bight of Africa with reflected solar
radiation from an orbiting mirror.I say when not used
for hurricane modulation the mirror could keep an
isolated part of the Atlantic Ocean warm enough
to grow floating carbon sequestering biologicals
or botanicals.
kitk on 02/14/2007 at 2:17 AM
50
We do not have anywhere near the knowledge to safely engineer planet-wide systems that fluctuate in natural cycles we always think are our own doing. Be a Geologist, and think very long-term.
If you want to cut human CO2 emissions, advocate (and practice) self-control, self-education, less sex and the better raising of the kids we have now. Otherwise, you will just keep handing them all the mess you have made--again.
Space mirrors are the stuff of Star Trek--at least 100 years down the road and sure to cause huge weather and crop problems if they actually work. So will high-altitude aerosols, along with possible cancer and asthma. Don't play Russian Roulette with the whole planet!
mbmurphy777 on 02/14/2007 at 11:29 AM
14
Sure, any intervention will have risks, but the risks of runaway climate change are non-negligable.
Expecting the world to adopt ascetic puritanical conservation is simply unrealistic. Banking on that strategy in isolation to solve the GHG problems is foolish.
Of course, the mirrors solution is unworkable, not just from a cost standpoint, but the solar wind would accellerate them out of position almost immediately... they'd essentially just be a huge solar sail afterall.
Combined with CO2 removal (see terra preta post above), stratospheric aerosols might be reasonable temporizing measures until other breakthroughs are available.
TMLutas on 02/18/2007 at 5:32 PM
1
It seems a rather foolish exercise in "moving the goal posts" to imagine catastrophic global warming in the next decade or two. Even the most alarmist of models do not foresee this level of change that soon. So why aim geoengineering solutions as short-term stopgaps?
rluna on 02/15/2007 at 2:58 PM
8
In my opinion the cheapest and most effective way to stabilize world climate would be to reforest the world. Deforestation is one of the key causes of destitute poverty in the third world. We could kill two birds with one stone. The problem with this approach is that there is no economic incentive to do it. However, using a combination of government regulators, private contractors, tax incentives, and carbon emission credit trading we could definitely create a workable model. This coupled with dissuading the practice of “slash and burn” for a more effective “char and burn” we could offset the effects of global warming. As for fossil fuels, we all know that as prices continue to rise we will see an increase in alternative fuels, and alternative fuel technology. With the help of government sponsored research and tax incentives, and government infrastructure investments we could be well on our way to an alternative fuel future. However, replacing our carbon based energy and automobile infrastructure in timely manner is not economically feasible. The only way to mitigate the effects of CO2 production is to increase the size of the world’s forest.
mbmurphy777 on 02/17/2007 at 8:11 PM
14
http://ergosphere.blogspot.com/2006/11/sustainability-energy-independence-and.html
Pyrolyze biomass... waste as well as some dedicated energy crops (heat in a restricted O2 atmosphere), run the resultant pyrolysis gases (which contain about 1/2 the energy of the biomass) through a solid oxide fuel cell to convert them to electricity at 50% (already better than the standard 30% for steam turbines and rapidly improving) efficiency. The rest of the biomass is converted into charcoal (pure carbon) and ash (minerals); the carbon can then be buried (or run through a direct carbon fuel cell to get more electricity).
If buried, this will have the effect of sequestering the CO2 (charcoal is very stable and non toxic) out of the atmosphere (the biomass pulls it out of the atmosphere and incorporates it into the plant cell wall) allowing us to go carbon negative). This would be about 30% of the biomass by weight. The charcoal can even be blended into soil to improve crop yields (by helping soil to hold on to water and nutrients), thus replenishing lost top soil:
http://www.eprida.com/home/index.php4
As noted in this essay, the CO2 given off by the SOFC exhaust could be sequestered by algae, creating biodiesel and starch (which can be converted into ethanol). This could then be used as transportation fuel or heating oil. Alternatively, this could be fed back into the pyrolysis process to capture even more CO2.
The biomass pyrolysis scheme noted above could replace a fair portion of fosil fuel consumption for electrical generation (50%, and that number could go up if SOFC efficiencies continue to climb)... thus displacing tons of CO2 production AND at the same time sequester nearly 1/2 billion tons of carbon (the equivalent of approximately 1.5 billion tons per year of CO2).
It's a good read worth checking out, especially since I think energy independence is as important as GHG emission control!
evaneco on 02/17/2007 at 11:12 PM
1
When we found out FREON was harming the ozone layer (FREON being a substitute for ammonia that was killing people a generation earlier), we found many non-ODS substitutes now contribute to global warming.
So now we gain a rudimentary idea of what are the actual mechanics of climate change and have zero chance of forseeing the potential problems with seeding the upper atmosphere with nanoparticles.
And you want to do what?
chipengineer on 02/18/2007 at 11:45 AM
2
This experiment has been done naturally countless times - with major volcanic eruptions. The effect is clear in the temperature record, and is one of the better understood effects included in the climate models.
TallDave on 02/18/2007 at 5:51 PM
1
We'd best do more looking before leaping. We can always REDUCE solar radiation; increasing it would be vastly more difficult.
thomasjschum on 02/19/2007 at 10:00 PM
1
To get around this we could use wave-action powered pumps to move nutrient-rich deep-ocean water to the surface where the nutrients will support plankton. The plankton removes carbon and revitalizes the lowest layers of the food chain, sort of a double benefit. A PDF drawing of this is the first download on my website.
Website link is http://mysite.verizon.net/vzesfls5/files/
blunney on 02/20/2007 at 12:48 PM
13
Makes building nukes seem sort of Rube Goldberg, doesn't it? All you need is a lot of sand, a lot of energy (to power the crushers and fans), and a pissy attitude - sort of like Iran!
Seriously, the whole problem is economic in nature. Two billion people with access to coal who want food, housing, electricity, modern conveniences and transportation NOW aren't going to worry about the consequences in fifty years.
Today's beach house is tomorrow's beach front. Mass dislocation and migration costs money and is messy. Norway starts looking like a desirable address. Things are going to change - get used to it.
The earth's climate isn't static, even if humans only burn our dinner, live in the grass, and chase wildebeests. Civilization has just recently (like the last 100 years) stopped looking at the ground long enough to see what's happening in the sky. No way are we wise enough to predict the long term trends of the climate, much less our own actions. Neither are we wise enough to admit it.