World's leading climate scientist expresses opinion to Kyoto Protocol

The West's approach to fighting global warming, enshrined in the Kyoto protocol, simply will not work, one of the world's leading climate scientists says. The struggle by the developed countries to cut back their emissions of carbon dioxide (CO2), the main greenhouse gas, will always be overtaken by the rising new emissions of the developing nations, led by China and India, which are not parties to the Kyoto treaty, says Professor Wallace Broecker of Columbia University, New York. Only radical new technologies for extracting carbon dioxide directly from the air will be able to halt global warming, says the professor, widely regarded as one of the fathers of climate-change studies. "What you guys are tinkering around with in Kyoto is just a drop in the bucket."

Dr Broecker's criticism of Kyoto centres on the fact that the treaty at present commits only the rich, industrialised countries of the West to cut their carbon emissions. The developing nations, led by China and India, are not yet required to do anything. But their burgeoning economic development is largely powered by burning coal and other fossil fuels, and the soaring CO2 emissions that this will produce will far outweigh the cuts that could be brought about by all the energy conservation and alternative energy schemes of the West, Dr Broecker says. Emerging techniques for extracting CO2 direct from the air, liquefying it and then storing it, he says, offer the only realistic hope of preventing a level of climate change that would be catastrophic for the world. He says it is a practical solution that could be achieved without excessive cost.

The much-lauded Dr Broecker, 73, professor of geology at Colombia's Lamont-Doherty Earth Observatory, is the world's leading interpreter of the Earth's operation as a linked biological, chemical and physical system. In the 1980s he identified the great world-wide "conveyor belt" of ocean currents that plays a key role in regulating the planet's climatic states. In July 1987, he set out his fears in a celebrated paper in Nature, the leading science journal, entitled "Unpleasant Surprises in the Greenhouse?", which was perhaps the first widely noticed sounding of the global warming alarm.

"No one knows what lies in the active chamber of the gun, but I am less optimistic about its contents than many," he says now. Techniques for extracting CO2 directly from the air are being developed by United States researchers, including colleagues of Dr Broecker at Columbia. The problem is not "capturing" CO2 but its eventual storage, as the volumes involved are huge: the size of the world's present yearly CO2 output, when liquefied, would be about 25 cubic kilometres. Dr Broecker thinks this can be stored in exhausted oil wells, saltwater aquifers or even at the bottom of the sea, although his preferred option would be to "mineralise" it, by absorption into silicon-bearing rock. "Alternative energy, and energy conservation, although very valuable, are going to fall far short of stopping the build-up of CO2," he says, "but extracting CO2 direct from the air can do the job."