Humans currently release about 70 million tons of carbon dioxide every day into the atmosphere and about 20 million tons is being absorbed regularly by the oceans, causing the pH to drop. Chris Sabine describes current and projected future impacts of this acidification on marine ecology.
Climate scientist Michael MacCracken explores some of the scientific, legal, and ethical implications of "geo-engineering" options that have been proposed by some people to address global climate change.
The ocean is the largest solar energy collector on Earth. More than 90 percent of the warming that has happened on Earth over the past 50 years has occurred in the ocean. Not all of that heating is detectable at the surface because currents move some of the heat to deeper layers of water, where it can "hide" for years or decades.