Planning for 'Sustainable Retreat'

"Here, in its oversimplified essence, is Lovelock's doomsday scenario: Rising heat means more ice melting at the poles, which means more open water and land. That, in turn, increases the heat (ice reflects sunlight; open land and water absorb it), causing more ice to melt. The seas rise. More heat leads to more intense rainfall in some places, droughts in others. The Amazon rain forests and the great northern boreal forests --the belt of pine and spruce that covers Alaska, Canada and Siberia --undergo a growth spurt, then wither away. The permafrost in northern latitudes thaws, releasing methane, a greenhouse gas that is twenty times more potent than CO2 -- and on and on it goes.

In a functioning Gaian world, these positive feedbacks would be modulated by negative feedbacks, the largest of which is the Earth's ability to radiate heat into space. But at a certain point, the regulatory system breaks down and the planet's climate makes the jump -- as it has many times in the past -- to a new, hotter state. Not the end of the world, but certainly the end of the world as we know it.

In Lovelock's view, modest cuts in greenhouse-gas emissions won't help us -- it's too late to stop global warming by swapping our SUVs for hybrids. What about capturing carbon-dioxide pollution from coal plants and pumping it underground? "We can't possibly bury enough to make any difference." Biofuels? "A monumentally stupid idea." Renewables? "Nice, but won't make a dent." To Lovelock, the whole idea of sustainable development is wrongheaded: "We should be thinking about sustainable retreat."

Retreat, in his view, means it's time to start talking about changing where we live and how we get our food; about making plans for the migration of millions of people from low-lying regions like Bangladesh into Europe; about admitting that New Orleans is a goner and moving the people to cities better positioned for the future.

For water, the answer is pretty straightforward: desalination plants, which can turn ocean water into drinking water. Food supply is tougher: Heat and drought will devastate many of today's food-growing regions. It will also push people north, where they will cluster in cities. In these areas, there will be no room for backyard gardens. As a result, Lovelock believes, we will have to synthesize food -- to grow it in vats from tissue cultures of meats and vegetables. It sounds far out and deeply unappetizing, but from a technological standpoint, it wouldn't be hard to do.

As a last resort, to keep the planet even marginally habitable, Lovelock believes that humans may be forced to manipulate the Earth's climate by erecting solar shades in space or building devices to strip huge quantities of CO2 out of the atmosphere."