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Debate: Geoengineering, solar shading

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-===Side-effects: Are there significant environmental side effects from solar shading?=== 
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-*'''Solar shields can be adjusted according to effects.''' [ Russel Dovery. "Supervillainy: Astroengineering Global Warming". Kuro5hin. 8 Apr. 2005]: "The reduction in incoming sunlight would be 0.5 to 1%, enough to neatly stop global warming and keep temperatures stable. It would give us time to stabilise our emissions, then start the long process of filtering greenhouse gases back out of the atmosphere and storing them somewhere. The Lens can of course be adjusted, so as greenhouse gas levels dropped the diffusion effect would be reduced as well, until we reached a point where the Lens was no longer required and could be safely dismantled, or more playfully used to frighten the hell out of everyone in a medium-sized nation with an appropriate orbital insertion to enter the Earth's atmosphere flat-on." 
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-*'''[[Argument: Solar shading would reduce sunlight received by plants| Solar shading would reduce sunlight received by plants]]''' Solar shading would reduce the amount of sun light that hits the surface of the earth. This would reduce the amount of sunlight that plants can use as energy in the process of photosynthesis, which may damage individual plants and have a negative effect on ecosystems. 
-*'''Solar shading will decrease surface evaporation/rain.''' Solar shading will reduce the amount of sunlight that hits bodies of water, which will reduce precipitation in some places.  
-*'''Solar shading may increase Eurasian 'winter warming'.''' This is related to shifts in the wind patterns and is seen in the aftermath of volcanoes. 
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=== Sulfur dioxide: Is injecting sulfur dioxide into the atmosphere a good idea? === === Sulfur dioxide: Is injecting sulfur dioxide into the atmosphere a good idea? ===

Revision as of 21:05, 29 September 2008

Should solar shading be part of plans to reverse global climate change?


Background and Context of Debate:

Use of solar shades is a proposed approach to the mitigation of global warming through planetary engineering. By intentionally changing the Earth's albedo, or reflectivity, scientists propose that we could reflect more heat back out into space, or intercept sunlight before it reaches the Earth through a literal shade built in space. A 0.5% increase in albedo is believed capable of roughly halving the effect of CO2 doubling.

The debate regarding solar shading revolves around numerous questions: Is global warming irreversible, making geoengineering a necessary, last-resort? Even if we are able to cut and even eliminate greenhouse gas emissions, what should be done about the greenhouse gases that are still in the atmosphere? Are these quantities of greenhouse gases sufficient to continue the process of global warming? Does this make solar shading a necessary effort to reduce atmospheric greenhouse gases? Is geoengineering generally consistent with environmental ethics? Are any of the environmental risks worth taking if solar shading has a chance of effectively fighting global warming? What are the specific pros and cons of the various approaches to solar shading: space-shield, sulfur dioxide, space ring, and others?

Global warming crisis: Is solar shading a reasonable solution?


Catherine Brahic. "Solar shield could be quick fix for global warming". New Scientist. 5 June 2007 - "A solar shield that reflects some of the Sun's radiation back into space would cool the climate within a decade and could be a quick-fix solution to climate change, researchers say."
  • Solar shield reverses global warming; emissions reductions do not Robert Roy Britt. "No Stopping it Now: Seas to Rise 4 Inches or More this Century". LiveScience. 17 Mar. 2005 - "Even if all industrial pollution and auto emissions suddenly ceased today, Earth's climate will warm at least 1 degree by the year 2100 and seas will rise 4 inches (11 centimeters), according to a new study...The warming is likely to continue through 2400, another study forecasts...The worst-case scenario projects the global average temperature rising 6.3 degrees Fahrenheit within this century and the sea level climbing a foot or more..."Many people don't realize we are committed right now to a significant amount of global warming and sea level rise because of the greenhouse gases we have already put into the atmosphere," said Gerald Meehl, who led the study out of the National Center for Atmospheric Research (NCAR)."
  • Solar shading need not "replace" clean-energy or dampen efforts. University of Arizona astronomer Roger Angel, who is studying global warming: "The sunshade is no substitute for developing renewable energy, the only permanent solution." In general, only misperceptions can lead to conclusions that sunshades are "replacing" approaches to cutting emissions.
  • Solar shading stops global warming and buys time to cut emissions.


  • Geoengineering is just as likely to damage the environment as help Ken Caldeira at the Carnegie Institution of Washington told New Scientist: "Personally, as a citizen not a scientist, I don't like geo-engineering because of the high environmental risk. It's toying with poorly understood complex systems. I think the Earth's system is so complicated that our interfering with it is very likely to screw things up and very unlikely to improve things. And this is the only planet we have."[1]
  • Solar shading reduces sunlight energy available to solar panels By reducing the amount of sunlight that enters the atmosphere, solar shading decreasing the amount of energy available to solar energy cells. This is cause for concern because solar energy is a major source of 0-emission power, and so a significant solution to the global warming crisis. To diminish this solution is to weaken the fight against global warming.

Geoengineering ethics: Is geoengineering ethical?


  • Humans already changed climate; geoengineering is not new/wrong. Bryan Wassh. "6. Geoengineering". Time, What's Next in 2008: "the truth is, we're already performing an unauthorized experiment on our climate by adding billions of tons of man-made carbon dioxide to the atmosphere. Unless the geopolitics of global warming change soon, the Hail Mary pass of geoengineering might become our best shot." �
  • Irreversible climate change makes geoengineering unavoidable. It is impossible for humans to avoid geoengineering in the future. The earth's climate has always shifted dramatically throughout its history. The Earth will, for instance, enter another ice age fairly soon. Should we, then, just allow this to happen? No, particularly if it means sacrificing millions of human lives and civilization as we know it. We should make the world work for us, not allow it to obliterate us. And, if we assume geoengineering is enevitable, then there is no moral boundary to doing it now, when global warming poses the threat that does to human civilization.
  • Arguments against geoengineering/solar-shading are too illusive. Ken Caldeira at the Carnegie Institution of Washington: "We have been trying to pinpoint the one really bad thing that argues against geoengineering the climate. But it is really hard to find."[3]


  • It is unethical to change planet without universal approval (impossible). Richard Somerville, a climate researcher at Scripps Institution of Oceanography in California: "I should say right up front, I am not at all in favour of geoengineering. I think it's inherently unethical. I don't see how you decide on the basis of all humanity how to change the planet."[4]
  • Private control of geoengineering projects has great risks. Alan Robock. "20 reasons why geoengineering may be a bad idea". Bulletin of the Atomic Scientist. 2008: "15. Commercial control of technology. Who would end up controlling geoengineering systems? Governments? Private companies holding patents on proprietary technology? And whose benefit would they have at heart? These systems could pose issues analogous to those raised by pharmaceutical companies and energy conglomerates whose products ostensibly serve the public, but who often value shareholder profits over the public good."

Space shield: Is a space-based sun-shield a good idea?


  • Sunshield costs are reasonable in face of global warming Russel Dovery. "Supervillainy: Astroengineering Global Warming". Kuro5hin. 8 Apr. 2005 - "Dr Benford, while doing most of the work himself, has exploited his friends at NASA to confirm that the engineering is viable, and the results were astounding: The whole project could be achieved with today's technology at a cost of $10 billion US dollars up-front, and another ten for maintenance over the decades of designed lifespan. That's a lot of money, but it's still about two-fifths of the initial appropriation from Congress for the Iraq war. Benford proposes an international collaboration between wealthy nations to spread the load, and I would also suggest commercial sponsors. This would make the project almost indecently viable, considering the return each nation would get from being able to ignore Kyoto and its successors for as long as they feel like."
  • A space shield does not affect Earth's ozone like particle shading. Shading the earth through sulfur particles has the very negative consequence of damaging the Earth's atmosphere. A space shield does not have this consequence, as it acts outside of the the Earth's atmosphere, in space, to block a small percentage of the sun's rays.


  • There are better ways to fight global warming than geoengineering. Mike MacCracken, chief scientist for climate change projects at the Climate Institute in Washington DC, said in 2006: "If I'm going to put satellites in orbit, why not put energy generating satellites that capture solar energy and beam it down to Earth?. Rather than blasting sulphur into the stratosphere, why not invest in other kinds of energy systems, such as wind energy or ocean energy, that don't cause these kinds of problems? There's a lot to do well before you get to geoengineering."[5]
Roger Angel, a University of Arizona Regents' Professor - "It seems feasible that it could be developed and deployed in about 25 years at a cost of a few trillion dollars. With care, the solar shade should last about 50 years. So the average cost is about $100 billion a year, or about two-tenths of one percent of the global domestic product."
This stands at odds to those that have proposed that a solar shade would cost 10 billion. Many would argue that $100 billions per year for 25 years would be too expensive, compared to the alternatives.[7]

Sulfur dioxide: Is injecting sulfur dioxide into the atmosphere a good idea?


Bryan Wassh. "6. Geoengineering". Time, What's Next in 2008.: "the price tag: somewhere between a few hundred million dollars and a couple of billion dollars a year, compared with the unknowable cost of decarbonizing the entire world."
  • Sulfur dioxide solar shielding has gained scientific credibility. idea gained significant credibility in 2006, when Nobel Prize—winning atmospheric scientist Paul Crutzen published an editorial examining the possibility of releasing vast amounts of sulfurous debris into the atmosphere to create a haze that would keep the planet cool.
  • Volcanoes perform solar shading; why is it wrong for humans to do so? Volcanoes have erupted for centuries, sending thousands of megatons of sulfates and other chemicals into the atmosphere, which have had a cooling effect on the climate. Why then is it wrong for humans to do the same, for the purpose of maintaining a stable climate and global environment?


  • Injecting sulphates into the atmosphere would destroy the ozone Ken Caldeira, from the Carnegie Institution Department of Global Ecology at Stanford University in California, said in 2006: "I don't think we can get it right. One of the problems of putting sulphate particles in the stratosphere is that it would destroy the ozone layer; so you might solve the global warming problem, but then we'd all die of that."[8]
  • Volcanic clouds do great damage, don't justify solar shading Natural volcanic explosions and clouds have been used as an analogy and justification for geoengineering. Yet, it is important to recognize that volcanic clouds have been highly damaging to the environment. They are, therefore, a poor basis for justifying solar shading.
  • Solar shading may warm the tropopause and lower stratosphere.
  • Sulphate solar shading may increase acid rain.[10] Injecting sulphate into the atmosphere will increase the acidity of clouds and rain.

Space ring: Is a space ring around the earth a good idea?


  • A solar ring would protect hottest areas on Earth. A solar ring "shades the tropics primarily, providing maximum effectiveness in cooling the warmest parts of our planet," according to Jerome Pearson, president of Star Technology and Research Inc.[11]


  • A space ring would be far to expensive. "Space Ring Latest Implausible Warming Solution". "The journal Acta Astronautica has published what is probably the most outlandish suggestion yet to stop global warming on Earth - a planet-girdling ring of small particles or micro-spacecraft with reflective umbrellas...The price tag? Oh, about $6 trillion to $200 trillion for the particle solution. Much less for spacecraft."

Pro/con sources



See also

External links

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