Researchers have speculated about several processes that could regulate ocean temperatures. As surface waters warm, more water evaporates, which can increase cloud cover and winds that cool the surface. In some areas, warming alters ocean currents in ways that bring in cooler waters. In addition, the very process of evaporation removes heat.
"This year, 2008, is the International Year of the Reef, and we need to go beyond the dire predictions for coral reefs and find ways to conserve them," Kleypas says. "Warming waters are just one part of the picture, but they are an important part. As we evaluate how and where to protect reefs, we need to determine whether the ocean thermostat offers some protection against coral bleaching."
Kleypas and her co-authors say more research needs to be conducted on the thermostat. In particular, scientists are uncertain whether global warming may alter it, raising the upper limit for sea-surface temperatures. Computer model simulations tend to capture the slow rate of warming in the western Pacific over the last few decades, but they show the warm pool heating rapidly in the future.
"Computer models of Earth's climate show that sea-surface temperatures will rise substantially this century," says NCAR scientist Gokhan Danabasoglu, a co-author of the study. "Unfortunately, these future simulations show the Western Pacific Warm Pool warming at a similar rate as the surrounding areas instead of being constrained by a thermostat. We don't know if the models are simply not capturing the processes that cause the thermostat, or if global warming is happening so rapidly that it will overwhelm the thermostat."
|Contact: David Hosansky|
National Center for Atmospheric Research/University Corporation for Atmospheric Research