Sea Level Rise: How the Oceans Respond to a Warming World

Josh Willis Scientist Jet Propulsion Laboratory Pasadena, CA As the planet heats up, over 80 percent of the excess heat goes toward warming the oceans. In essence, the oceans are the Earth's heat capacitors, absorbing the heat from global warming and setting the time scale for climate change. As they warm, ocean waters expand, causing sea level rise. Rising ocean levels are one of the most serious and visible consequences of global warming. However, projections of future sea level rise remain very crude and have so far underestimated the actual rate of rise. To accurately project sea level rise, it is important to understand its causes. Since 2003, two new global ocean observing systems have begun to address this issue. The Argo array of profiling floats now provides nearly global observations of temperature and salinity in the upper ocean, and the Gravity Recovery and Climate Experiment (GRACE) satellites provide monthly estimates of the ocean's total mass. Using data from these and other instruments, the first attempts to explain the causes of present data sea level rise have been made. Results suggest that although warming and thermal expansion played a large role in sea level rise during the 1990s, the melting of glaciers and ice sheets is accelerating and may have become the dominate source in recent years.

Location: Seaver Science Library, Rm 150

Audiences: Everyone Is Invited

Contact: April Mundy