1. Sea Level & Ice Sheets
Concern about the Future of Inhabited Coastlines
Presented by
Julie Brigham-Grette
and Beth Caissie
View of ice free world, with sea level at 73 m, new York harbor.
(thanks to Ken Miller, Rutgers, for many of his slides)

2. Sources: Petit et al. (1999) Nature 399, 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. Global Sea Level Last interglacial 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
Satellite elevation data and a variety of geological records are combined to portray the surface topography of the Antarctic Ice Sheet near the Ross Ice Shelf. Above, a digital elevation model derived from satellite data shows the ice sheet today. By synthesizing various geological records, scientists have also estimated how the ice sheet is thought to have looked 20,000 years ago (bottom) at the time of the last maximum extent of glatiation. In West Antarctica, the ice sheet is most vulnerable to future change.Credit: Robert Bindschadler, NASA

9. Ice shelves and sea ice do not contribute to sea level but they can buttress the land ice sheets from rapid retreat.
Hannes Grobe AWI, wiki art

10. West Antarctica can come & go!

11. Should I Sell My Shore House?
How long will it take to achieve Gore World 5 m rise?
= sea level at last major interglacial 125,000 y ago: IPCC2001: years; IPCC yr
New: Greenland surging much sooner, but >>100 yr
Otto-Bleisner et al. (2006) simulation
125,000 y ago last interglacial
The future: IPCC

12. Brazil
Geologist mantra:
If it happened before, it could happen again!
Atlantic City NJ

13. Observations (Tide Gauge and Satellite Altimetry Data)
Overall 10-20cm rise in 20th century
Accepted value of 1.7±0.3mm/yr 20th century
±0.3mm/yr

14. Accelerating Sea Level Rise (1993-2003)
JPL NASA
Rate of sea level rise from accelerated to 3.1±0.7 mm/yr
Sea level rise varies spatially
Western Pacific and Eastern Indian Ocean have seen the largest
fluctuations in sea level due to increased average sea level coupled with
ENSO events

15. Causes of Sea Level Rise
Melting of glaciers, ice caps, ice sheets
Thermal expansion of sea water
Small scale changes due to anthropogenic land water storage (damming rivers, over-pumping of water and fuels, wetland and forest destruction)
Relative changes in sea level due to tectonic movements (land subsidence or rebound)

16. Why Is Global Sea Level Is 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
Melting Glaciers & Ice Caps:
Melting land ice adds to ocean volume, but not sea ice
Alpine
IPCC2001

17. Cartoon x-section of ice sheet

18. Why Is Global Sea Level Is Rising Today?
Melting Mountain Glaciers and Ice Caps:
Alpine glaciers 0.6 mm/yr
Greenland Ice Cap IPCC2001: near 0
Cazenave & Nerem (2004): >0.15 mm/yr
New data: increased from 0.23 mm/y 1996 to 0.57 mm/y 2005 (Sterns & Hamilton 2007) .

19. 2005
2007

20. Greenland Mass Balance Estimates
GRACE - NASA/German Aerospace Center Gravity Recovery and Climate Experiment
SWIPA II -- Snow Water Ice and Permafrost in the Arctic, module 2 from the Arctic Council
SWIPA II, 2009

21. Higher CO2: Predicted Global Warming
IPCC Third Assessment Report: Climate Change Synthesis Report
IPCC Fourth Assessment Report 2007

22. Sea-Level Forecast: IPCC 2001 & 2007
40 cm (1.25 ft) rise by 2100, 1 m (3.3 ft) by IPCC 2001 error estimate: cm
IPCC 2007 error: cm (does not include ice sheet melting)
2001
2007
Check the right diagram

23. We are tracking high end predictions
Thermal expansion greater: ‘93-03 data 1.6 m/myr
Not IPCC ±20 cm
Best estimate 80 cm global; max. 1 m can’t be rules out
Rahmsdorf et al. (2007)
Increase in heat W/m2
Willis et al. (2004)

24. 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.
This graph shows several recent estimates for global sea level rise, presented here relative to the 1990 level.
Please refer to the original publications for the various assumptions underlying these scenarios!
The full references are:
Church, J.A. and N.J. White, 2006: A 20th century acceleration in global sea-level rise. Geophysical Research Letters 33(1): p. L01602.
Rahmstorf, S., 2008: A semi-empirical approach to projecting future sea-level rise. Science 315(5810): p
Vellinga, P. et al. 2008: Exploring high-end climate change scenarios for flood protection of the Netherlands. International Scientific Assessment
Carried out at request of the Delta Committee. See
WBGU - Wissenschaftlicher Beirat Globale Umweltveränderungen, 2006: The Future Oceans - Warming Up, Rising High, Turning Sour. Berlin, 110 pp. Available at
Rahmstorf
Data

25. Sea level rise data from
Guilford, CT
Sea level rise data from around the world

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

27. 80 cm-1m in 100 yrs with subsidence making it worse in some places Insurance Rates?Disaster relief?
Both need forecasting and planning

28. Bangladesh: 17 million displaced 22nd century
Ammerman & McClennen 2000

29. Greenland (= 6 m of sea level) is thinning now But did not disappear during the last Interglacial

30. How a 1 m rise of sea level
will affect the Nile Delta
Would impact
6.1 Millon people
4500 km2 cropland

31. Sea Level Rise a small rise of sea level
across a low lying coastal plain translates
into a significant advance of the sea
or retreat of the shoreline
coastal environments retain their original profile
as they “roll” landward with rising sea level

32. Sea Level Rise – like this? No !
(from Day After Tomorrow)
Sea Level Rise – like this?
No !
Gradual sea level rise and storm events causing this?
Highly likely!

33. Exercise: Rates of Sea Level Change Future projections
Mitigating Risks
CCSP 1.4, US Govt report