1. The Sea Level Rise Story Bruno Tremblay McGill University bruno.tremblay@mcgill.ca Slide from Steven Nerem – University of Colorado

2. Annual Global Mean Surface Temperatures [Hansen et al., 2005]

3. Observed Sea Level Rise

4. Observed Sea Level Rise Last 20 Kyr BP

5. Measuring sea level height Tidal gauge Radar altimetry

6. Cause of Sea Level Rise Eustatic: Water mass added. Steric: Salinity or temperature change Isostatic: Change in the level of land (e.g. thermal effect, plate tectonic, compaction effect) Withdrawal of ground water  land subsidence. Cooling of volcanic island  land subsidence.

7. Short Term Changes in Sea Level Diurnal-semidiurnal tides Atmospheric pressure – Winds - Evaporation- precipitations Water density and currents El Niño/southern oscillation Water mass exchange between Arctic, Atlantic, Pacific, Indian Oceans River runoff/floods Seiches Tsunamis Abrupt change in land level

8. Potential Sea Level Rise Glaciers: 0.5 m Greenland: 6m Antarctica West: 6m East: 51m

9. Potential Sea Level Change Contributions Thermal Expansion: ~1 meter Mountain Glaciers: 0.5 meters Greenland Ice Melt: 7 meters Antarctic Ice Melt: 60 meters Land Water Storage: < 0.5 meters

10. Recent contribution to observed sea level rise

12. Rhone Glacier 1900 2008

14. Alaska Mass Change from Grace

15. Ice Sheet Mass Balance 8 mm/yr of precip and calving at equilibrium

16. Greenland Ice Mass Loss from GRACE Credit: Roger Braithwaite 362 Gt = 1 mm GMSL -210 Gt/year = 0.6 mm/year GMSL

18. Antarctic Ice Mass Flux from InSAR SLR 0.4 to 0.6 mm/yr -114 km 3 /yr - 37 ±20 km 3 /yr +33 km 3 /yr -38 km 3 /yr +48 km 3 /yr -2 km 3 / yr +5 km 3 /yr -22 km 3 /yr -3 km 3 /yr +5 km 3 /yr -2 km 3 /yr -56 km 3 /yr -2 km 3 /yr +21 km 3 /yr -4 km 3 /yr -33 km 3 /yr -4 km 3 /yr - 49 ±20 km 3 /yr [Rignot, 2005] GRACE

19. Ice Sheet - Ice Shelf

20. Wilkins Ice Shelf Larsen B Ice Shelf

21. Antarctica Without Ice

22. Recent contribution to observed sea level rise

23. Sea Level Observations versus Predictions [Rahmstorf et al., 2007] Tide Gauge Observations Satellite Observations Climate Model Predictions (IPCC 3rd Assessment, 2001)

24. What to Expect in the Future The IPCC 4th Assessment: 0.28 - 0.59 m by 2100 Recent study suggests higher rates (0.5 - 1.4 m by 2100). [Rahmstorf, 2007] 1.4 ° 5.8 °

25. Greenland Ice Mass Loss Estimates Luthcke et al. [2006] Krabill et al. [2004] Zwally et al. [2005] Rignot et al. [2006] Velicogna and Wahr [2005] Ramillien et al. [2006] Chen et al. [2006] Velicogna and Wahr [2006] [Cazenave, 2006] 362 Gt = 1 mm GMSL

26. Antarctic Ice Mass Loss Estimates Rignot and Thomas [2002] Zwally et al. [2005] Davis et al. [2005] Velicogna and Wahr [2006] Chen et al. [2006] Ramillien et al. [2006] [Cazenave, 2006] 362 Gt = 1 mm GMSL

27. Effects of Sea Level Rise 1 meter 2 meters 4 meters 8 meters GFDL