Study Doubts Dumping Iron in Ocean Will Halt Climate Change

A proposal to fight global warming by dumping iron into Antarctic waters to fertilize microscopic algae would fail to do much good, even if done for 100 years, a study suggests.

The plan to boost production of the algae, which would then consume greater amounts of carbon dioxide, would not significantly reduce the atmosphere’s load of the gas, a chief culprit in causing the expected warming, scientists said in today’s issue of the British journal Nature.

Carbon dioxide and other gases in the atmosphere trap energy that radiates away from Earth, the greenhouse effect that keeps the globe warmer than if the energy escaped into space. Many scientists believe that increases in these gases will result in an increase in global warming, disrupting agriculture and causing a destructive increase in sea level.

The new study suggests that, even if the fertilization worked well over a century of continuous Antarctic dumping, the resulting reduction in atmospheric carbon dioxide would be about 10%, give or take 5%.

The basic problem is that too little water would be available for storing more carbon dioxide, said Tsung-Hung Peng of the Oak Ridge National Laboratory in Oak Ridge, Tenn., who did the study with Wallace Broecker of Columbia University’s Lamont-Doherty Geological Observatory in Palisades, N.Y.

The research used computer simulations to determine how much Antarctic water would get a chance to store the gas.

Jorge Sarmiento, a researcher at Princeton University’s Atmospheric and Oceanic Sciences Program, said his simulations suggest the carbon dioxide reductions might be larger. But he agreed that “this is not likely to be a significant contributor to mitigating increases in carbon dioxide.”

The new study came in response to recent work by scientists at Moss Landing Marine Laboratories in Monterey Bay, Calif.