Oceans key to global climate
MOST OF the debate on climate change focuses on greenhouse gases released into the atmosphere. But it has emerged that ocean circulation has an equally important role. It was believed that the severe cooling the earth underwent 2.7 million years ago was caused by changes in carbon dioxide (CO ) levels.
2 But analyses of ocean sediments (2.5 millionto 3.3 million-year-old) suggest the cooling happened due to the emergence of subsurface ocean currents. These currents absorb heat and CO from winds blowing close to the
2 ocean surface in the Atlantic and release them in the Pacific. Science, October 23 (online)