Nov. 7, 2006 — Efforts to tackle global warming through politics are falling so pitifully short of what is needed that ideas dismissed just a few years ago as weird science are now getting a serious hearing.
Abandoned by the United States, the world's biggest single polluter, and with China, the No. 2 polluter, exempt from targeted emissions cuts, the U.N.'s Kyoto Protocol in its present shape will not even dent the greenhouse-gas problem.
Years of denial, bickering and nit-picking by interest groups have so delayed and crimped the political response that schemes to stave off climate disaster which previously were written off as mad or dangerous are being given a closer look.
"They are becoming part of the debate, although the reservations about them remain very deep," says one of the world's most respected climatologists, Jean Jouzel of France's National Centre for Scientific Research (CNRS).
One novel idea is for a gigantic sunshade in space.
It comes from Roger Angel, a professor at the University of Arizona and one of the world's top authorities on optics.
His "solar shield" would comprise a spider's web of struts holding six tiltable mirrors that would deflect some of the Sun's rays away from Earth, reducing solar energy reaching our planet by two percent — enough to compensate, at least in part, for the warming effect caused by carbon emissions.
The web, measuring some 1,200 miles across, would be placed at a permanent vantage point called the Earth-Sun L1 Lagrange position, almost 950,000 miles from home.
Those who write off Angel as crazy should also tell NASA, whose Institute for Advanced Concepts (NIAC) last month asked him to flesh out the basic proposal into something more detailed.
Angel estimates the cost at roughly $3 trillion, a sum that many would say is ludicrously beyond reach. He retorts that the bill is just one to two percent of the world's gross national product (GNP), which is surely a fair price when compared with the cost of global warming.
In 2001, for instance, the insurance giant Swiss Re, in a report commissioned by the United Nations, estimated that an increase in natural disasters as a result of global warming could cost the world over $300 billion annually by the year 2050.
A simpler idea for planetary cooling is supported by Dutch 1995 Nobel chemistry prize laureate Paul Crutzen, famous for his work on the ozone hole.
Crutzen suggests releasing sulphur dioxide particles in the upper atmosphere that would reflect sunlight (and thus heat) back into space.
After a few years, the dust would fall to the land or the sea, but while it is being borne around by the stratospheric winds, it would have a cooling effect.
A spur for the particle idea was the discovery that after Mount Pinatubo erupted in the Philippines in 1991, so much volcanic ash was spewed out that over the next couple of years, Earth's surface cooled by up to 0.9 degrees F: a perceptible but not excessive change.
Edouard Bard, a professor at the College de France in Paris, warns though that the Pinatubo phenomenon is complex and poorly understood.
The global average temperature drop after 1991 masked "very significant variations" regionally, with extreme falls in the northwestern Atlantic, in the Middle East and North Africa and paradoxically a prolonged warming in northern Europe, Bard noted.
Such big, quick swings can have a big localized impact on wildlife and the food chain, for instance by encouraging algae proliferation that can choke coral reefs.
