1. The Challenge of Projecting Future Sea Levels in the Chesapeake Bay Region Donald F. Boesch February 18, 2014 Severn River Association

2. MVN RSM Program 2008 Climate Change Impact Assessment climatechange.maryland.gov

3. MVN RSM Program Climate Action Plans climatechange.maryland.gov

4. MVN RSM Program Updating SLR Projections climatechange.maryland.gov

5. MVN RSM Program Sea Level Had Been Stable 2000 Years 0.0 0.2 -0.2 0.4 -0.4 meters Kemp et al. 2011. Proc. National Acad. Sci Tide gauges Paleo-reconstruction

6. MVN RSM Program Global Mean Sea Level by Satellite Altimeter sealevel.colorado.edu

7. MVN RSM Program What Causes Sea Level To Change?

8. MVN RSM Program World Ocean is Warming

9. MVN RSM Program 9 9 Velicogna 2009 GRL Polar Ice Sheet Loss

10. MVN RSM Program NRC Global Sea-Level Rise Projections National Research Council. 2012. Sea-Level Rise for the Coasts of California, Oregon and Washington: Past, Present and Future. global mean sea level rise from 2000 best estimates

11. MVN RSM Program Fingerprints of Polar Ice Sheet Melting West Antarctica Greenland

12. MVN RSM Program Do You Have A Sinking Feeling? Florida Maryland New York New England Early Interglacial Late Interglacial The glacial forebulge collapses and land surface subsides

13. MVN RSM Program Slowing of Gulf Stream Raises Sea Level Based on work of Tal Ezer and colleagues, Old Dominion University J. Geophysical Research 118:685 Gulf Stream strength Tide gauge level trends

14. MVN RSM Program How Much Will Sea Level Rise in Maryland?

15. MVN RSM Program Sea-Level Rise Will Not Stop in 2100 Schaeffer et al. 2012 Nature Climate Change 2: 867. ending all emissions in 2016 stabilizing at 2ºC

16. MVN RSM Program Intergovernmental Panel on Climate Change 5 th Assessment It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20 th century. Limiting climate change will require substantial and sustained reductions of greenhouse gas emissions. www.ipcc.ch

17. MVN RSM Program How Much Has It Warmed? www.ipcc.ch about 0.9°C or 1.6°F Global average land and ocean temperature

18. MVN RSM Program How Much Will it Warm? www.ipcc.ch Global average surface temperature 7.2°F 3.6°F It mainly depends on how much greenhouse gases we emit. RCP8.5 = ‘business as usual’ continued growth in emissions RCP2.6 = rapid reductions in GHG emissions to 0 by 2070

19. MVN RSM Program How Much Will the Seas Rise? www.ipcc.ch Unlike temperature, sea level rise does not stabilize during century

20. MVN RSM Program Elicitation of Estimates by Experts

21. MVN RSM Program Expert elicitation Expert elicit. Expert elicitation Unrestrained emissions Drastic reductions 83% 17% 83% 17% 95% 5% 95% 5% IPCC NRC 2012 2100 2050 0.5 1.0 1.5 NRC 2012 0 Global Mean Sea-Level Rise (meters) Unrestrained emissions Drastic reductions

22. MVN RSM Program Maryland 2100 2050 1 2 3 4 5 Maryland Relative Sea-Level Rise (feet) New Jersey Miller et al. 2013. AGU Earth’s Future

23. MVN RSM Program Consequences of Sea-Level Rise Light blue Light blue: salt marshes Greens Greens: < 2 m, suscept- ible to innundation Orange-yellow Orange-yellow: 2-4 m, susceptible to storm surge Greater Bay volume, ocean influence

24. MVN RSM Program Tidal Wetlands and Sea-Level Rise Kirwan & Megonigal 2013. Nature 404:53 Human activities have significant consequences for stability

25. Questions or Comments? boesch@umces.edu www.umces.edu/people/president @DonBoesch