New field of climate engineering offers quick fixes but there are risks
Michael Wilner, Straits Times 4 Jul 09;
SCIENTISTS are now toying with a grand idea - harnessing technology to alter the earth's climate and combat global warming. They are working in a field of science still in its infancy known as climate engineering or geoengineering.
Among the more modest, but ambitious, proposals being put forward is to populate the earth with 'synthetic trees', essentially high-tech towers armed with special absorbents that scrub and store carbon dioxide from air particles.
Professor Klaus Lackner, a geophysicist at Columbia University who came up with the idea, told The New York Times that such synthetic trees could be 'planted' within two years. He admitted their cost would be high but said this could potentially be offset by the stored carbon dioxide, which could be sold commercially.
Prof Lackner is among those who have cautioned that the earth's climate may be past the point of no return, and that small, individual efforts to prevent climate change may be too little, too late. These scientists believe geoengineering may provide a quick fix for an immediate environmental crisis.
'The idea is that you want to ready some option that you'll have available if you have some sort of emergency, and you learn you need to respond quickly,' Professor David Victor, of the University of California at San Diego and an adjunct senior fellow for science and technology for the Council on Foreign Relations, told The Straits Times.
Climate manipulation may come in many forms, though experts differ on which are most effective or beneficial.
Solar radiation management, a theory that Prof Victor considers the most prominent, would reduce warming of the planet by reflecting Earth-bound sunlight back into space. Scientists say this could be achieved by launching billions of aluminium balloons to act as orbital mirrors, or by injecting the stratosphere with sulphur aerosols, which also reflect sunlight.
Another geoengineering method is cloud brightening, a process by which salt water from the sea is sprayed thousands of metres in the air to produce thicker, more reflective clouds.
All of these methods, in theory, would reduce Earth's radiation intake from the sun. But none have been tested, and all could be risky. Dangers could include typical seasonal pattern disruption, drought and famine threats to Europe and Africa, and deterioration of the ozone layer.
Along with the risks of research and deployment come two moral quandaries: whether deliberate climate manipulation is ethical, and who gets to decide whether or not to move forward.
Governance was a key topic at a recent conference held by the United States National Academy of the Sciences. Professor Alan Robock, a climatologist at Rutgers University, said a major point of debate was how to define 'planetary emergency' - and who, ultimately, identifies the tipping point.
