Space mirror (anti-global warming measure)
Encyclopedia
The use of space mirrors as an anti-global warming measure is one of a series of proposals made to the United States
government for reducing global warming
.
At the "Response Options to Rapid or Severe Climate Change" round-table meeting organized by the President's Climate Change Technology Program
in September 2001 to gather ideas for averting climate change, one of the proposals was to station one or more wire-mesh "mirrors" in orbit to deflect sunlight back into space or to filter it. The idea was proposed by Lowell Wood
, a senior staff scientist at Lawrence Livermore National Laboratory
, who calculated that deflecting 1% of sunlight would restore climatic stability, and that that would require either a single mirror 600000 square miles (1,553,992.9 km²) in area or several smaller ones. Wood had been researching the idea for more than ten years but considered it so infeasible that it should only be a back-up plan for solving the global warming problem. In January 2007, The Guardian
reported that the US government was recommending that research on sunlight deflection, including space mirrors, be continued as "insurance" and that the next United Nations Report on Climate Change
advocate such a strategy. In addition to the space mirror, suggested sunlight-reducing techniques included launching thousands of highly reflective balloons and pumping sulphate droplets into the upper atmosphere to emulate volcanic emissions.
Space mirrors were first considered in the 1980s as a way to cool the climate of Venus. James Early, also at Livermore, in 1989 proposed using a "space shade" 2,000 kilometers in diameter orbiting at Lagrangian Point L1
. He estimated the cost at between one and ten trillion US dollars and suggested manufacturing it on the moon using moon rock.
Using space mirrors to reduce the impact of sunlight falls into the category of geoengineering
: deliberately modifying the earth's climate. At a conference on the topic organized by Daniel Schrag
of Harvard University
and David Keith
of the University of Calgary
in November 2007, the consensus was that it was worth studying such ideas further despite their high cost, the doubtful feasibility of some including the space mirror, and the risk of their distracting attention from reduction of greenhouse gas
emissions.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
government for reducing global warming
Global warming
Global warming refers to the rising average temperature of Earth's atmosphere and oceans and its projected continuation. In the last 100 years, Earth's average surface temperature increased by about with about two thirds of the increase occurring over just the last three decades...
.
At the "Response Options to Rapid or Severe Climate Change" round-table meeting organized by the President's Climate Change Technology Program
U.S. Climate Change Technology Program
The United States Climate Change Technology Program or CCTP is a multi-agency planning and coordination entity. Its purpose is to accelerate the development and deployment of technologies that can reduce, avoid, or capture and store greenhouse gas emissions. CCTP was established administratively in...
in September 2001 to gather ideas for averting climate change, one of the proposals was to station one or more wire-mesh "mirrors" in orbit to deflect sunlight back into space or to filter it. The idea was proposed by Lowell Wood
Lowell Wood
Lowell Wood is an American astrophysicist who has been involved with the Strategic Defense Initiative and with geoengineering studies. He has been affiliated with Lawrence Livermore National Laboratory and the Hoover Institution, and chaired the EMP Commission. Wood invented the Mosquito laser.-...
, a senior staff scientist at Lawrence Livermore National Laboratory
Lawrence Livermore National Laboratory
The Lawrence Livermore National Laboratory , just outside Livermore, California, is a Federally Funded Research and Development Center founded by the University of California in 1952...
, who calculated that deflecting 1% of sunlight would restore climatic stability, and that that would require either a single mirror 600000 square miles (1,553,992.9 km²) in area or several smaller ones. Wood had been researching the idea for more than ten years but considered it so infeasible that it should only be a back-up plan for solving the global warming problem. In January 2007, The Guardian
The Guardian
The Guardian, formerly known as The Manchester Guardian , is a British national daily newspaper in the Berliner format...
reported that the US government was recommending that research on sunlight deflection, including space mirrors, be continued as "insurance" and that the next United Nations Report on Climate Change
IPCC Fourth Assessment Report
Climate Change 2007, the Fourth Assessment Report of the United Nations Intergovernmental Panel on Climate Change , is the fourth in a series of reports intended to assess scientific, technical and socio-economic information concerning climate change, its potential effects, and options for...
advocate such a strategy. In addition to the space mirror, suggested sunlight-reducing techniques included launching thousands of highly reflective balloons and pumping sulphate droplets into the upper atmosphere to emulate volcanic emissions.
Space mirrors were first considered in the 1980s as a way to cool the climate of Venus. James Early, also at Livermore, in 1989 proposed using a "space shade" 2,000 kilometers in diameter orbiting at Lagrangian Point L1
Lagrangian point
The Lagrangian points are the five positions in an orbital configuration where a small object affected only by gravity can theoretically be stationary relative to two larger objects...
. He estimated the cost at between one and ten trillion US dollars and suggested manufacturing it on the moon using moon rock.
Using space mirrors to reduce the impact of sunlight falls into the category of geoengineering
Geoengineering
The concept of Geoengineering refers to the deliberate large-scale engineering and manipulation of the planetary environment to combat or counteract anthropogenic changes in atmospheric chemistry The Intergovernmental Panel on Climate Change concluded in 2007 that geoengineering options, such...
: deliberately modifying the earth's climate. At a conference on the topic organized by Daniel Schrag
Daniel P. Schrag
Daniel P. Schrag is Sturgis Hooper Professor of Geology, Professor of Environmental Science and Engineering, Director of the University Center for the Environment, and Director of the Laboratory for Geochemical Oceanography at Harvard University. He is also an external professor at the Santa Fe...
of Harvard University
Harvard University
Harvard University is a private Ivy League university located in Cambridge, Massachusetts, United States, established in 1636 by the Massachusetts legislature. Harvard is the oldest institution of higher learning in the United States and the first corporation chartered in the country...
and David Keith
David Keith (scientist)
David W. Keith is a Canadian environmental scientist. He is the former director of the Institute for Sustainable Energy, Environment and Economy Energy and Environmental Systems Group at the University of Calgary. Keith is noted for his work in carbon dioxide air capture, and has been featured on...
of the University of Calgary
University of Calgary
The University of Calgary is a public research university located in Calgary, Alberta, Canada. Founded in 1966 the U of C is composed of 14 faculties and more than 85 research institutes and centres.More than 25,000 undergraduate and 5,500 graduate students are currently...
in November 2007, the consensus was that it was worth studying such ideas further despite their high cost, the doubtful feasibility of some including the space mirror, and the risk of their distracting attention from reduction of greenhouse gas
Greenhouse gas
A greenhouse gas is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. The primary greenhouse gases in the Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone...
emissions.