Climate computer models predict that man-made global warming should cause the temperatures in the world's oceans to rise. Last year, researchers at the Scripps Oceanographic Institute reported that they had found "Clear Evidence of Human-Produced Warming in World's Oceans." Now a new study by National Oceanographic and Atmospheric Administration researchers and colleagues finds "Recent Cooling of the Upper Ocean." They note:
The decrease represents a substantial loss of heat over a 2-year period, amounting to about 21% of the long-term upper-ocean heat gain between 1955 and 2003. . . These findings suggest that the observed decrease in upper ocean heat content from 2003 to 2005 could be the result of a net loss of heat from the Earth to space. Nevertheless, further work will be necessary to determine the exact cause of the cooling.
The researches point out that one of the implications of their findings is:
…this variability is not adequately simulated in the current generation of coupled climate models used to study the impact of anthropogenic influences on climate. Although these models do simulate the long-term rates of ocean warming, this lack of interannual variability represents a shortcoming that may complicate detection and attribution of human-induced climate influences.
Interestingly, lower ocean temperatures should have led to lower sea level rise (heat causes water to expand), but it didn't. The explanation may rest with two papers published in Science last week.
One paper using data from satellite measurements of changes in gravity found that glaciers in Greenland may be melting faster than earlier studies had suggested thus contributing more water to average sea level rise. In addition, another study found that snowfall in Antarctica had not significantly increased as climate computer models suggested would occur as the planet warmed. This is bad news with regard to sea level since the accumulation of extra snow in Antarctica would offset the contribution to sea level rise of glacial melting elsewhere.