Read Online The Best Australian Science Writing 2013 by Jane McCredie - Free Book Online Page A
Authors: Jane McCredie
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all say, with Darwin, âI thinkâ â and genuinely do so.
Creationism
Modest, not!
Earthmasters: Playing God with the climate
Clive Hamilton
As the effects of global warming begin to frighten us, geoengineering will come to dominate global politics. Scientists and engineers are now investigating methods to manipulate the Earthâs cloud cover, change the oceansâ chemical composition and blanket the planet with a layer of sunlight-reflecting particles. Geoengineering â deliberate, large-scale intervention in the climate system designed to counter global warming or offset some of its effects â is commonly divided into two broad classes. Carbon dioxide removal technologies aim to extract excess carbon dioxide from the atmosphere and store it somewhere less dangerous. This approach is a kind of clean-up operation after we have dumped our waste into the sky. Solar radiation management technologies seek to reduce the amount of sunlight reaching the planet, thereby reducing the amount of energy trapped in the atmosphere of âgreenhouse Earthâ. This is not a clean-up but an attempt to mask one of the effects of dumping waste into the sky, a warming globe.
Diligent contributors to Wikipedia have listed some 45 proposed geoengineering schemes or variations on schemes. Eight or ten of them are receiving serious attention. Some are grand inconception, some are prosaic; some are purely speculative, some are all too feasible; yet all of them tell us something interesting about how the Earth system works. Taken together they reveal a community of scientists who think about the planet on which we live in a way that is alien to the popular understanding. Let me give a few examples.
It is well known that, as the sea ice in the Arctic melts, the Earth loses some of its albedo or reflectivity â white ice is replaced by dark seawater which absorbs more heat. If a large area of the Earthâs surface could be whitened then more of the Sunâs warmth would be reflected back into space rather than absorbed. A number of schemes have been proposed, including painting roofs white, which is unlikely to make any significant difference globally. What might be helpful would be to cut down all of the forests in Siberia and Canada. While it is generally believed that more forests are a good thing because trees absorb carbon, boreal (northern) forests have a downside. Compared to the snow-covered forest floor beneath, the trees are dark and absorb more solar radiation. If they were felled the exposed ground would reflect a significantly greater proportion of incoming solar radiation and the Earth would therefore be cooler. If such a suggestion appears outrageous it is in part because matters are never so simple in the Earth system. Warming would cause the snow on the denuded lands to melt, and the situation would be worse than before the forests were cleared.
More promisingly perhaps, at least at a local scale, is the attempt to rescue Peruvian glaciers, whose disappearance is depriving the adjacent grasslands and their livestock of their water supply. Painting the newly dark mountains with a white slurry of water, sand and lime keeps them cooler and allows ice to form; at least that is the hope. The World Bank is funding research.
Another idea is to create a particle cloud between the Earthand the Sun from dust mined on the moon and scattered in the optimal place. This is reminiscent of the US militaryâs âblack cloud experimentâ of 1973, which simulated the effect on the Earthâs climate of reducing incoming solar radiation by a few per cent. Consistent with the long history of military interest in climate control, the study was commissioned by the Defense Advanced Research Projects Agency, the Pentagonâs technology research arm, and carried out by the RAND Corporation, the secretive think tank described as âa key institutional building block of the Cold War American
Creationism
Modest, not!
Earthmasters: Playing God with the climate
Clive Hamilton
As the effects of global warming begin to frighten us, geoengineering will come to dominate global politics. Scientists and engineers are now investigating methods to manipulate the Earthâs cloud cover, change the oceansâ chemical composition and blanket the planet with a layer of sunlight-reflecting particles. Geoengineering â deliberate, large-scale intervention in the climate system designed to counter global warming or offset some of its effects â is commonly divided into two broad classes. Carbon dioxide removal technologies aim to extract excess carbon dioxide from the atmosphere and store it somewhere less dangerous. This approach is a kind of clean-up operation after we have dumped our waste into the sky. Solar radiation management technologies seek to reduce the amount of sunlight reaching the planet, thereby reducing the amount of energy trapped in the atmosphere of âgreenhouse Earthâ. This is not a clean-up but an attempt to mask one of the effects of dumping waste into the sky, a warming globe.
Diligent contributors to Wikipedia have listed some 45 proposed geoengineering schemes or variations on schemes. Eight or ten of them are receiving serious attention. Some are grand inconception, some are prosaic; some are purely speculative, some are all too feasible; yet all of them tell us something interesting about how the Earth system works. Taken together they reveal a community of scientists who think about the planet on which we live in a way that is alien to the popular understanding. Let me give a few examples.
It is well known that, as the sea ice in the Arctic melts, the Earth loses some of its albedo or reflectivity â white ice is replaced by dark seawater which absorbs more heat. If a large area of the Earthâs surface could be whitened then more of the Sunâs warmth would be reflected back into space rather than absorbed. A number of schemes have been proposed, including painting roofs white, which is unlikely to make any significant difference globally. What might be helpful would be to cut down all of the forests in Siberia and Canada. While it is generally believed that more forests are a good thing because trees absorb carbon, boreal (northern) forests have a downside. Compared to the snow-covered forest floor beneath, the trees are dark and absorb more solar radiation. If they were felled the exposed ground would reflect a significantly greater proportion of incoming solar radiation and the Earth would therefore be cooler. If such a suggestion appears outrageous it is in part because matters are never so simple in the Earth system. Warming would cause the snow on the denuded lands to melt, and the situation would be worse than before the forests were cleared.
More promisingly perhaps, at least at a local scale, is the attempt to rescue Peruvian glaciers, whose disappearance is depriving the adjacent grasslands and their livestock of their water supply. Painting the newly dark mountains with a white slurry of water, sand and lime keeps them cooler and allows ice to form; at least that is the hope. The World Bank is funding research.
Another idea is to create a particle cloud between the Earthand the Sun from dust mined on the moon and scattered in the optimal place. This is reminiscent of the US militaryâs âblack cloud experimentâ of 1973, which simulated the effect on the Earthâs climate of reducing incoming solar radiation by a few per cent. Consistent with the long history of military interest in climate control, the study was commissioned by the Defense Advanced Research Projects Agency, the Pentagonâs technology research arm, and carried out by the RAND Corporation, the secretive think tank described as âa key institutional building block of the Cold War American
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