From The Atlantic:

For decades environmentalists have fought to save our oceans from the perils of overfishing, climate change, and pollution. All noble efforts -- but what if environmentalists have it backwards? What if the question is not how to save the oceans, but how the oceans can save us?

That is what a growing network of scientists, ocean farmers, and environmentalists around the world is trying to figure out. With nearly 90 percent of large fish stocks threatened by over-fishing and 3.5 billion people dependent on the seas as their primary food source, these ocean farming advocates have concluded that aquaculture is here to stay.

Seaweed is one of the fastest growing plants in the world; kelp, for example, grows up to 9-12 feet long in a mere three months.

Of course, the seaweed grown to mitigate emissions would need to be harvested to produce carbon-neutral biofuels to ensure that the carbon is not simply recycled back into the air as it would be if the seaweed is eaten.

For more, see: The Coming Green Wave: Ocean Farming to Fight Climate Change