Comment & Debate
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.
Sharon Begley. “The ‘Geo-Engineering’ Scenario”. Newsweek. Nov 23, 2007 – The physics of geo-engineering is not in dispute. Studies of volcanoes established what amount of particles produces how much cooling, as well as how the particles spread and how long they remain aloft (a year or two). Knowing this, it should be possible to roll back the global warming projected for 2100 enough to return the planet to its climate of 1900, Damon Matthews and Ken Caldeira of the Carnegie Institution reported in June.
James Early. “Space-based solar shield to offset greenhouse effect”. British Interplanetary Society, Journal (ISSN 0007-084X), vol. 42, Dec. 1989, p. 567-569. – Abstract. The construction of a thin glass shield is proposed to offset the greenhouse effects caused by CO2 buildup in the earth’s atmosphere. It is suggested that the shield could be built from lunar materials and should be located near the first Lagrange point of the earth-sun system. Consideration is given to the photon thrust of the shield, the shield size, effective blockage, and possibilities for shield design.
“The Solution to Global Warming. A $10 Billion Sun shield for planet Earth”. Android World.com. Retrieved 19 Sept. 2008 – The proposal is to build a very large orbiting shield which will intercept sunlight before it reaches the Earth and reflect it back into space. The shield will consist of a very thin metal foil covering a sparse matrix of ribs. In order to minimize the cost, the materials needed for this shield will come from the Moon. The shield will be built robotically both to save cost and because humans are not suited to working in space. How large a shield will be necessary? Our initial estimate is 6 percent of the cross-sectional area of the Earth. Since the cross-sectional area of Earth is about 50 million square miles, the shield will need to be about 3 million square miles (roughly the size or area of Australia). Since the shield will orbit the Earth, it will only intercept sunlight when it is on the sunny side of the Earth. Thus the effect of the shield will be to reduce incident radiation from the Sun by about 3%. How long will it take to build this shield? Suppose that we could build one square mile in the first year of assembly. By doubling the effort each year thereafter (through the expansion of our Lunar manufacturing facilities), we could complete the shield in about 22 years. Including three years of startup, the entire project could be completed in 25 years. One additional year would double the size of the shield to 6 million square miles and give a reduction of 6% in the incident sunlight (if this were deemed necessary).
David Adam and Liz Minchin. “US urges scientists to block out sun”. Sydney Morning Herald. 29 Jan. 2007 – THE US wants the world’s scientists to develop technology to block sunlight as a last-ditch way to halt global warming.
It says research into techniques such as giant mirrors in space or reflective dust pumped into the atmosphere would be “important insurance” against rising emissions, and has lobbied for such a strategy to be recommended by a UN report on climate change, the first part of which is due out on Friday).
…The US response [to a 2007 IPCC report] says the idea of interfering with sunlight should be included in the summary for policymakers, the prominent chapter at the front of each panel report. It says: “Modifying solar radiance may be an important strategy if mitigation of emissions fails. Doing the R&D to estimate the consequences of applying such a strategy is important insurance that should be taken out. This is a very important possibility that should be considered.”
Jerome Pearson, president of Star Technology and Research, Inc. – “Reducing solar insolation by 1.6 percent should overcome a 1.75 K [3 degrees Fahrenheit] temperature rise. This might be accomplished by a variety of terrestrial or space systems.”[1]