Elements of Sea Level in a Changing Climate

Abstract: 

We survey aspects of global and regional sea level, focusing on physical mechanisms accounting for sea level change in the past century and introducing potential future changes. We start by exploring global mean sea level changes arising from ocean heating (thermosteric sea level rise) and from changes to the ocean mass (barystatic rise). Regional sea level variations can be large relative to the global mean, and are thus a primary concern for sea level impacts on coasts. Examples of regional variations include fluctuations due to natural modes of climate variability (e.g., Pacific Decadal Variability, North Atlantic Oscillation, Atlantic Meridional Overturning Circulation), and from mass redistributions that alter the static equilibrium sea level (i.e., the geoid). Scenarios for future global mean sea level changes typically include an upward trend due to ocean warming, thus continuing the trend seen for much of the 20th century. Less certain is our ability to project changes involving changes to large-scale circulation patterns, such as the Atlantic overturning, as well as changes to ice sheets. We conclude by speculating on mechanisms for ocean-induced ice sheet melt arising from potential changes to the Antarctic Circumpolar Current and the Antarctic coastal current.

This is a joint CCRC/Fluid Dynamics seminar and is suitable for a general audience.