Two of Britain's best known scientists proposed Wednesday to curb global warming by sowing the world's oceans with thousands, perhaps millions, of giant vertical pipes 100-to-200 meters deep. "We need a fundamental cure for the pathology of global heating," wrote James Lovelock and Chris Rapley in a letter to the British journal Nature. "Emergency treatment could come from stimulating the Earth's capacity to cure itself." As the planet's atmosphere heats up, they explained, certain cyclical processes that normally regulate climate are beginning to amplify the process of warming rather than holding it in check. When Arctic sea ice recedes further each year, for example, sunlight falls on heat-absorbing blue water rather than white snow and ice which reflects heat back into space, accelerating the warming process. Lovelock and Rapley suggest that climate change may have already pushed Earth past the "tipping point" beyond which this, and other disrupted cycles, become part of a self-reinforcing, "positive feedback" loop. They look to the world's oceans, which cover more than 70 percent of the planet's surface, for a solution. Free-floating or tethered pipes with one-way flaps some 10 metres in diameter, they conjecture, would increase the mixing of nutrient-rich waters below the surface with the warmer -- and relatively barren -- waters at the ocean's surface. "This upper layer is almost free of algae and of nutrients and is an ocean desert," Lovelock explained in and e-mail to AFP. "We wondered if we could restore algal growth with its capacity to draw down carbon dioxide" -- the major cause of global warming -- "and to emit dimethyl sulphide, the precursor of clouds." As with ice in the Arctic, white clouds reflect back much of the sun's heat. But clouds do not form spontaneously from water vapour -- they require chemical elements called condensation nuclei such as dimethyl sulphide, which plays a critical role in regulating the marine climate.
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