Can smoke and mirrors ease global warming?

The London Convention, part of the International Maritime Organisation, will review ocean fertilization at a meeting this week. Among those hoping for approval for tests is Margaret Leinin, chief science officer of California-based Climos, a company that is looking at ways to use oceans to soak up greenhouse gases. “The world has not been able to get carbon emissions under control,” Leinin said. “We should look at other options.” Climos is seeking to raise money to test adding iron dust to the southern ocean to spur growth of algae that grow by absorbing heat-trapping carbon dioxide from the air. When algae die, they fall to the seabed and remove carbon.

Other short-cut ideas include spraying a smoke of tiny particles of pollutants into the sky to dim sunlight, or even deploying a vast thin metallic barrier in space, with 100 space shuttle flights, to deflect the sun’s rays. The UN Climate Panel said world greenhouse gas emissions from human activities rose 70 per cent between 1970 and 2004. But it said that fertilising the oceans or dimming the sun “remain largely speculative and unproven, and with the risk of unknown side-effects.” “More evidence has been coming in since then, but it’s far from making a reliable case for geo-engineering,” said Terry Barker, head of the Cambridge Center for Climate Change Mitigation Research and one of the leading authors of the UN panel report. The seas are already suffering enough from a “chemical soup” of pollution from humans, he said. “There’s no need to add to the mess.”

With fears of recession and amid the deepest financial crisis since the 1930s, some governments may find cheap geo-engineering attractive compared with reducing carbon emissions. “It would be shortsighted,” Baker said.

Last year, the London Convention said that “knowledge about the effectiveness and potential environmental impacts of ocean iron fertilization currently was insufficient to justify large-scale operations.” Those doubts were “still valid,” the Convention’s Coenen said. Firms like Australia’s Ocean Nourishment, Atmocean in New Mexico and Climos are working on sea-based projects. Another start-up, Planktos, indefinitely suspended operations in February after failing to raise cash.

Some like Climos hope that sucking carbon into the ocean, if it works, could qualify for credits as carbon trading. “It is possible to design experiments to avoid harm to the oceans,” said Leinin. Climos wants to test iron fertilization in the southern ocean, in January 2010 in a test that could $15-20 million, she said. If it works, Leinin said it could be one of the cheapest ways to combat global warming. Among objections are that carbon makes water more acidic and could undermine the ability of shellfish, crabs or lobsters to build shells. That in turn could disrupt the marine food chain.

Backers of geo-engineering say the risks are slight compared to far bigger disruptions from climate change, stoked by human emissions of greenhouse gases, which could lead to heatwaves, floods, droughts, more disease or rising seas. “We are already bludgeoning nature,” said Victor Smetacek, a professor at the Alfred Wegener Institute in Germany, who is planning an iron sulphate fertilization experiment off Antarctica in early 2009. His institute will cooperate with India to disperse 20 tonnes of iron sulphate near South Georgia over 300 sq kms. “Iron has a very positive effect. Added to the ocean it’s like water in the desert,” he said.

“We don’t have space to store the carbon we are producing on land,” he said of proposals including planting more forests.