Sea Level & Ice Sheets Concern about the Future of Inhabited Coastlines

1. Sea Level & Ice Sheets Concern about the Future of Inhabited Coastlines Presented by Beth Caissie (thanks to Ken Miller, Rutgers, for many of his slides)

2. Sources: Petit et al. (1999) Nature 399, 429-436 and National Oceanic and Atmospheric Administration (NOAA), USA

3. Sea level history over the past 450,000 years Source: Labeyrie et al (2003) In: Paleoclimate, Global Change and the Future, Springer.

4. Last interglacial Global Sea Level TODAY Full Glacial Lambeck et al., 2002, based on tropical & subtropical records

6. Ice from the Ocean makes ice sheets, so sea level drops • When Ice sheets melt, sea level goes up.

7. Antarctica West East

8. Why Is Global Sea Level Rising Today? • Melting Ice Caps and Glaciers: • Melting land ice adds to ocean volume (sea ice does not) • Greenland is thinning today, but didn’t disappear during the Last Interglacial . • IPCC2001: near 0 • Cazenave & Nerem (2004): >0.15 mm/yr • Sterns & Hamilton (2007): 0.57 mm/y

9. Why Is Global Sea Level Rising Today? Muir Glacier • Glacial Retreat • Most glaciers world-wide are in retreat • Alpine glaciers contribute 0.6 mm/yr to sea level rise • Why are some advancing? • Increased snow 1941, William Field 2004, Bruce Molnia From the Glacier photograph collection. Boulder, Colorado USA: National Snow and Ice Data Center/World Data Center for Glaciology. http://nsidc.org/data/glacier_photo/repeat_photography.html

10. Why Is Global Sea Level Rising Today? • Thermal Expansion: • ocean has gained heat • Warmer water less dense global 20th century warming ~0.6°C • 1.6 mm/yr sea-level rise

11. Should I Sell My Shore House? Brazil Atlantic City NJ

12. Observations(Tide Gauge and Satellite Altimetry Data) • Overall 10-20cm rise in 20th century • 20th century average rate of sea level rise: 1.7±0.3mm/yr • 1950-2000 1.8±0.3mm/yr • 1993-2003 accelerated to 3.1±0.7 mm/yr

13. Sea-Level Forecast: IPCC 2007 40 cm (1.25 ft) rise by 2100 1 m (3.3 ft) by 2200 IPCC 2007 error: 20-60 cm (does not include ice sheet melting) 2007 http://www.realclimate.org/images/sealevel_1.jpg

14. Recent Global Sea Level Rise Estimates Slide from Rahmstorf web site Data: Church and White (2006) Scenarios 2100: 50 – 140 cm (Rahmstorf 2007) 55 – 110 cm (“high end”, Delta Committee 2008) Scenarios 2200: 150 – 350 cm (“high end”, Delta Committee 2008) Scenarios 2300: 250 – 510 cm (German Advisory Council on Global Change, WBGU, 2006) WBGU Delta Comm. Rahmstorf Data Best Estimate = 80 cm of SL Rise by 2100, 1 m is not out of the question

15. Long Beach Island, NJ Human stabilized 400 m Natural movement Courtesy N. Psuty

16. (from Day After Tomorrow) Sea Level Rise – like this? No ! Gradual sea level rise and storm events causing this? Highly likely! http://www.learnnc.org/lp/editions/cede_smsandvol/323

17. The Nile River Delta 1 m SL Rise would impact 6.1 Million people 4500 km2 cropland

19. Boston http://www.geo.umass.edu/stategeologist/frame_maps.htm