Presentation on theme: "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)"— Presentation transcript:
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)
Sources: Petit et al. (1999) Nature 399, and National Oceanic and Atmospheric Administration (NOAA), USA
Source: Labeyrie et al (2003) In: Paleoclimate, Global Change and the Future, Springer. Sea level history over the past 450,000 years
Lambeck et al., 2002, based on tropical & subtropical records TODAY Last interglacial Full Glacial Global Sea Level
Ice from the Ocean makes ice sheets, so sea level drops When Ice sheets melt, sea level goes up.
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 didnt disappear during the Last Interglacial IPCC2001: near 0 Cazenave & Nerem (2004): >0.15 mm/yr Sterns & Hamilton (2007): 0.57 mm/y
Muir Glacier 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. 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 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
Brazil Atlantic City NJ Should I Sell My Shore House?
Overall 10-20cm rise in 20th century 20 th century average rate of sea level rise: 1.7±0.3mm/yr ±0.3mm/yr accelerated to 3.1±0.7 mm/yr Observations (Tide Gauge and Satellite Altimetry Data)
Sea-Level Forecast: IPCC cm (1.25 ft) rise by m (3.3 ft) by 2200 IPCC 2007 error: cm (does not include ice sheet melting) 2007
Recent Global Sea Level Rise Estimates Delta Comm. WBGU Data 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) Slide from Rahmstorf web site Best Estimate = 80 cm of SL Rise by 2100, 1 m is not out of the question
Human stabilized Natural movement 400 m Long Beach Island, NJ Courtesy N. Psuty
Sea Level Rise – like this? No ! Gradual sea level rise and storm events causing this? Highly likely! (from Day After Tomorrow)
The Nile River Delta 1 m SL Rise would impact 6.1 Million people 4500 km 2 cropland