MIT OpenCourseWare http://ocw.mit.edu 15.023J / 12.848J / ESD.128J Global Climate Change: Economics, Science,and Policy Spring 2008 For information about citing these materials or our Terms of Use, visit: http://ocw.mit.edu/terms.Sea-level Rise Science and Impacts Travis Franck 15.023 / 12.848 / ESD.128 16 April 2008 Agenda • Discussion of IPCC reports and SLR estimates • Scientific controversy and the long tail • Social coastal-zone trends and impactsSLR HotspotsMotivation: Millions live near the coast Courtesy of the Socioeconomic Data and Applications Center, Columbia University. Used with permission. The World: Population Density, 2000. Center for International Earth Science Information Network (CIESIN),Columbia University; and Centro Internacional de Agricultura Tropical (CIAT). 2005. Gridded Population ofthe World Version 3 (GPWv3). Palisades, NY: Socioeconomic Data and Applications Center (SEDAC),Columbia University. Available at http://sedac.ciesin.columbia.edu/gpw.SLR Map of FloridaSLR Map BangladeshUS SLR TrendsCauses and Projections • Causes are thermal expansion, glacial melt, subsidence or uplift => Relative SLR • Historic: • Sea level rose at an average rate of about 1.8 mm/year during the years 1961-2003. The rise in sea level during 1993-2003 was at an average rate of 3.1 mm/year. It is not clear whether this is a long-term trend or just variability. • Projections • 9 to 88cm by 2100 (IPCC TAR, 2001) • 18 to 58cm, plus 10-20cm for polar glaciers (IPCC AR4, 2007) Source: http://www.epa.gov/climatechange/science/recentslc.htmlJoint Program SLR Estimates Sea Level Rise 2000-2100 (m) (thermal expansion + small glacial melt) 0.0 0.2 0.4 0.6 0.8 1.0 Probability Density0 1 2 3 4 5 6 7 No Policy CCSP 750 CCSP 550 Joint Program SLR Odds Sea Level Rise > 0.3mSea Level Rise > 0.6mNo Policy19 in 203 in 20Stabilize at 75017 in 201 in 25Stabilize at 65015 in 201 in 50Stabilize at 55011 in 20<1 in 400Stabilize at 4501 in 4< 1 in 400Large Ice Sheets and Dams • The IPCC and MIT ranges don’t include SLR because of Antarctica and Greenland • Two studies estimate much higher ranges (~0.8m to 1.5m) by 2100 • Chao et al. (2008) estimate that reservoirs and other inland water impoundments have held large amounts of mountain glacial melt • Historical sea-level estimate would be biased low Photograph of melting ice sheetremoved due to copyright restrictions. Economic and Social Trends • Historically, coasts have been important for commerce and travel • Vast amounts of trade enters the US via ship • Recent decades: population and capital investment along the coast has grown faster than the national average • Costs of tropical storms have increased dramatically in recent historyTotal losses per year from Atlantic tropical cyclones in 2005 dollars (11-year centered average) Billions 125100 Losses (US 2005 dollars) 75 50 25 0 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000Year Figure by MIT OpenCourseWare, adapted from Pielke Jr. et al., Natural Hazards Review, 2008. Economic and Social SLR Studies • Titus (1988) gave economic estimates of flooded US land value • Yohe et al (1996) show that information could lower costs dramatically if the markets could react accordingly • Gibbons and Nicholls (2006) show that people might make different choices than purely rational assumptions would dictate • Highlight: • Non-linearities in the social response • Limited foresight, bounded rationality • Value of information (econ)Coastal Zone Managers Perceptions • Recent Federal Studies: • NAS - “Potential Impacts of Climate Change on U.S. Transportation” • CCSP 4.1 - “Coastal Sensitivity to Sea Level Rise” • Coastal managers are not planning for future sea-level rise • New infrastructure projects could be at risk • Zoning and building codes could be refined or improved to reduce risk • If they have considered SLR, confusion over what values to consider Coastal Zone Issues • Fast economic growth • Large amount of critical infrastructure • Value natural ecosystems • Beaches for tourism and coastal protection • Wetlands for habitat, coastal protection, fishing • Non-climate environmental issues, including river runoff and sedimentation • How to manage coastal zones? • Benefit/cost? • Cost effectiveness? • Role of science?Questions? (Remember no class
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