Thursday, April 2, 2009
Scientists have long sought to unravel the combination of physical and biogeochemical processes responsible for the tight coupling between atmospheric carbon dioxide concentrations and Earth’s climate. Researchers suspect that the Southern Ocean may have provided a reservoir for atmospheric carbon dioxide during cold glacial periods, and that release of some of this carbon dioxide could help explain why atmospheric concentrations rose by roughly 50% during each of the last five deglaciations. In a Research Article in the 13 Mar 2009 Science, Anderson et al. reported that vigorous wind-driven upwelling in the Southern Ocean may have coaxed carbon dioxide out of deep waters and into the atmosphere during the last deglaciation, about 17,000 years ago. In a Perspective article, J. R. Toggweiler explains how a poleward shift of the westerly winds, drawing more carbon dioxide- and silica-rich water up to the surface, can account for these results.