The Science of geoengineering- timkering with the environment on a large scale-could offer an alternative strategy to fight global warming William J Broad
In the past few decades, a handful of scientists have come up with big, futuristic ways to fight global warming; Build sunshades in orbit to cool the planet. Tinker with clouds to make them reflect more sunlight back into space. Trick oceans into soaking up more heat-trapping green house gases.
Their proposals were relegated to the fringes of climate science. Environmentalists and main stream scientists said the focus should be on reducing green house gases and preventing global warming in the first place.
But now , in a major reversal, some of the world's most prominent scientists say the proposals deserve a serious look because of growing concerns about global warming.
Worried about a potential planetary crisis, these leaders are calling on governments and scientific groups to study exotic ways to reduce global warming, seeing them as possible fallback positions if the planet eventually needs a dose of emergency cooling. "We should treat these ideas like any other research and get into the mindset of taking them seriously," said Ralph J Cicerone, President of The National Academy of Sciences in Washington.
The plans and proposed studies are part of a controversial field known as geoengineering, which means rearranging the earth's environment on a large scale to suit human needs and promote habitability.
Cicerone, an atmospheric chemist will detail his arguments in favour of geoengineering studies in the August issue of the Journal Climate Change. Practising what he preaches, Cicerone is also encouraging leading scientists to join the the geoengineering frey.
In April, at his invitation, Roger P Angel, a noted astronomer at the University of Arizona, outlined a plan at the Academy's annual meet to put into orbit trillions of small lenses that would bend sunlight away from earth.
In addition, Cicerone recently helped a noble Laureate's geoengineering ideas gain acceptancy for publications. The Laureate, Paul J Crutzen of the Max Planck Institute for Chemistry in Germany, is a star of atmospheric science who won his noble in 1995. His paper newly examines the risks and benefits of trying to cool the planet by injecting Sulphur into the Stratosphere.
Geoengineering is no magic bullet, Cicerone said. But done correctly, he added, it will act like an insurance policy if the world one day faces a crisis of overheating, with repercussions like melting icecaps, droughts, famines, rising sea levels and coastal flooding.
The study of futuristic countermeasures began quietly in the 1960's, as scientists theorised that global warming caused by human-generated emissions might one day pose a serious threat.
Some scientists noted that the earth reflected about 30 percent of incoming sunlight back into space and absorbed the rest. Slight increases of reflectivity , they reasoned, could easily counteract heat-trapping gases, thereby cooling the planet. Dr Broecker of Columbia proposed doing so by lacing the stratosphere with tons of sulphur dioxide, as erupting volcanoes occasionally do. John Latham, an atmospheric physicist at the Center for Atmospheric Research and his colleagues unsuccessfully sought for many years to test whether spraying saltwater mists into low ocean clouds increases their reflectivity. Other plans called for reflective films to be laid over desserts or white plastic islands to be floated on the world's oceans, as ways to reflect more sunlight.
The general reaction to such ideas, said Alvia GasKill, President of a consulting Firm advocating geoengineering, has sometimes been of fear- " Afraid that we don't know what the consequences will be."
But geoengineering's advocates say human kind is already vastly alerting the global environment and simply needs to do so more intelligently-NYT News Service
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