Panel Regarding Sea- -Level Rise Level Rise Panel Regarding Sea - PowerPoint PPT Presentation

Panel Regarding Sea- -Level Rise Level Rise Panel Regarding Sea Public Policy Forum March 10, 2010 Donald F. Boesch

Sea- -Level Rise Panel Level Rise Panel Sea Don Boesch Don Boesch – Univ. Maryland Center for Environmental Science Craig Fulthorpe Craig Fulthorpe – University of Texas Institute for Geophysics Tim McGee Tim McGee – RADM US Navy (retired) Dave Jansen Dave Jansen– House Natural Resources Committee Staff MVN RSM Program MVN RSM Program

Gauges Measure Relative Sea- -Level Level Gauges Measure Relative Sea Measured by tide gauges MVN RSM Program MVN RSM Program

Relative Sea- -Level Trends Level Trends Relative Sea Sea level (m) relative to 2000 0.6 0.4 Global ocean mean 0.18 Sitka, AK -2.1 0.2 Los Angeles 0.8 0 Pensacola 2.1 San Fran. 2.0 -0.2 Galveston 6.4 Charleston 3.2 Baltimore 3.1 -0.4 Grand Isle, LA 9.2 -0.6 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Sea level rise rates over the periods of record indicated in mm/yr MVN RSM Program MVN RSM Program http://tidesandcurrents.noaa.gov/sltrends/sltrends.shtml

th Century Sea Post 19 th Century Sea- -Level Rise Level Rise Post 19 3.2 +/- 0.4 mm/yr (1993-present) Church et al. 2008 MVN RSM Program MVN RSM Program

Global Sea- -Level Rise Level Rise Global Sea Satellite altimeter MVN RSM Program MVN RSM Program http://sealevel.colorado.edu/

Sea- -Level Rise Is Not Uniform Level Rise Is Not Uniform Sea MVN RSM Program MVN RSM Program

Accelerated Loss of Land Ice Accelerated Loss of Land Ice Cumulative mean annual mass balance Continental Glaciers GRACE gravity field reference glaciers measurements all glaciers 1980 1985 1990 1995 2000 2005 2010 MVN RSM Program MVN RSM Program Velicogna 2009

Closing the SLR Budget Closing the SLR Budget Murphy et al. 2009 ARGO Cazenave & Llovel 2010 JASON-2 GRACE MVN RSM Program MVN RSM Program

Semi- -Empirical Projection of SLR Empirical Projection of SLR Semi Vermeer & Rahmstorf (2009) method IPCC (2007) projections r y / m m 2 . 3 @ n o t i c e j o r p r a e n i L MVN RSM Program MVN RSM Program

New Findings Since IPCC AR4 New Findings Since IPCC AR4 Altimeter trends (>3 mm/yr) vary with climate but continue. Contribution of polar ice sheets and glaciers is increasing. Regional variability due to non-uniform thermal expansion. Kinematic constraints on polar glaciers likely constrain SLR to 2 m during this century, more likely around 0.8 m. Submarine melting important in ice sheet mass loss. Empirical models based on temperature projections suggest 20 th century SLR at least twice that of IPCC. 6 m or more of SLR over several centuries likely to be locked in as a result of 21 st century warming. MVN RSM Program MVN RSM Program

Vulnerable Coastal Landscapes Vulnerable Coastal Landscapes NJ North Carolina MD DE DC VA MVN RSM Program MVN RSM Program

Some Critical Needs Some Critical Needs Sustained ocean observing system, particularly in areas influencing ice sheets. Models capable of reliable projections of land-ice melting and thermal expansion. Coastal system models capable of projecting inundation, tidal exchange, storm surge, estuarine ecosystem dynamics, and wetland and landform responses. Socioeconomic decision-making tools to inform adaptation decisions. MVN RSM Program MVN RSM Program

“Science is a way of trying not to fool yourself. Science is a way of trying not to fool yourself.” ” “ Richard Feynman Richard Feynman boesch@umces.edu www.umces.edu/president/