What's more, the oceans are already sopping up a net 7 billion tons of the carbon dioxide emitted by human activities each year. The gas seeps from the air directly into the surface waters around the world and is gradually making the upper ocean more acidic. By pumping carbon dioxide directly into the deep sea, nations could reduce the amount inadvertently entering the sunlit waters near the surface, where much of marine life makes its home. There's no perfect solution. And it's going to involve some hard choices eventually.
Carbon dioxide is the uninvited guest that shows up whenever coal, oil, or natural gas burn.
To keep this interloper out of the environment, engineers are exploring strategies to lock up the carbon before it can do any harm. In the past, sequestration strategies have focused on pulling carbon dioxide out of the stream of gases made by burning fossil fuels. In one standard technique, the exhaust bubbles up through an amine solvent, which absorbs the carbon dioxide and lets other gases escape. A newer concept would strip the carbon out of the fossil fuel before combustion, leaving behind an enriched hydrocarbon that could be further transformed into hydrogen. Power plants would burn the hydrogen, like they do natural gas, or hydrogen could provide electrical energy through highly efficient fuel cells.