A method for sequestering carbon that involves injecting carbon dioxide into the deep ocean has been dismissed too early, says a Commentary online this week in Nature Geoscience. The environmental damage caused by all the options for removing carbon from the atmosphere ― including deep-ocean injection ― should be carefully weighed up against each other and against the impacts of continuing increases in atmospheric carbon dioxide concentrations.

Ralph Keeling argues that tough choices need to be made in combating climate change. He suggests that some negative effects on the environment from human emissions of carbon dioxide are inevitable ― whether or not we decide to sequester carbon dioxide, and no matter which sequestration option we choose. The problem of fighting climate change then becomes one of finding the right balance between the global benefit of reducing anthropogenic greenhouse-gas forcing and the local damage from any of the options for carbon sequestration.