THE ATLANTIC OCEAN is the second largest of the worlds oceans, covering 31.7 million sq. mi. (82 million sq. km.) or a fifth of the Earth's surface. The Atlantic's role in global climate is well-studied, and although it is not entirely understood, it is profound. Understanding how the ocean both responds to, and affects, climate change is a challenge, given the Atlantic's expanse, mass, and both short and long term variability in its physical and chemical characteristics. Oceans, including the Atlantic, absorb most of the carbon dioxide emitted by human activity, and, thus, are extremely important for their role in mitigating the effects of increasing greenhouse gases in the atmosphere.

The immediate effects on the Atlantic of increased atmospheric greenhouse gases, most importantly carbon dioxide, include ...