The Warming & Waking of the Polar Ice

1. The Warming & Waking of the Polar Ice Dr. Robert Bindschadler Chief Scientist Hydrospheric and Biospheric Sciences Laboratory NASA Goddard Space Flight Center Robert.A.Bindschadler@nasa.gov

2. Get Ready For: • IPY-How big? • Cryospheric check-up • Ice sheets-the waking giant • Complex interactions • An IPY data set for all

3. Me (Athabasca Glacier, 1970) He’s a future glaciologist?

4. Polar Literacy • Go to the polar regions • beyond the Arctic or Antarctic Circles • Popular documentary films • “March of the Penguins” • Shackleton films or “Scott vs. Amundsen” • Cousteau documentaries • Hollywood Films • “Happy Feet” counts • “The Day After Tomorrow” doesn’t count • Touring Exhibits • Shackleton • A Friend Acting Strangely • Lectures • GVSU IPY lecture series

5. International Polar Year An international program of coordinated research to explore the polar regions, deepen understanding of polar interactions including their role in global climate, expand our ability to detect changes, and extend this knowledge to the public and decision makers.

6. IPY is BIG 50,000 scientists 63 countries $800M new money …and growing

7. IPY for the Public • Educational • Polar regions matter! • Participatory • Projects like Global Snowflake Network allow citizens to contribute to polar science • Exciting and Inspirational • Webcasts and media coverage will give you unprecedented access to the polar regions to meet the scientists, peek over their shoulders and share their discoveries

8. IPY website: www.ipy.org

10. The Cryosphere • Sea Ice • Seasonal Snow • Permafrost • Ice Sheets and Glaciers Roll the DVD! Get your copy after the show! A copy of the video can be found at: http://www.nasa.gov/vision/earth/environment/cryosphere.html

11. Sea ice Primary impact: heat balance (both local and global) Covers an area twice the size of the US

12. Decline of Perennial Arctic Pack Ice 1980 AREA (million km2) 2003 2007 SHATTERED the record for minimum sea-ice extent

13. Decline of Perennial Arctic Pack Ice 2007 SHATTERED the record for minimum sea-ice extent

14. Positive Feedback of Sea Ice Sea ice as a reflector 5X 37% of 2*CO2 global warming caused by ice-albedo feedback

15. Seasonal snow, lake and river ice Snow covers up to 40% of Northern Hemisphere land in winter Primary impact: water resource

16. Decreasing Snow Cover Source: D. Hall 10% decrease in NH winter snow extent since 1966—primarily in springtime Global snow amount remains unknown (+50%)

17. Permafrost Primary impact: infrastructure engineering 20% of surface land mass is permanently frozen

18. Permafrost is Melting "I went to school on the mainland, and when I came back, my house was gone.” (from Nome Nugget Newspaper)

19. Ice sheets and glaciers Primary impact: sea level 10% of Earth’s land area is ice-covered Ice sheets contain ~75% of all fresh water and can raise sea level 75 meters

20. Sea Level has been Rising 2.0 mm/a From Church and White, 2006

21. Ice Sheets and Glaciers matter NOW: B. Richmond, USGS

22. Ice Sheets matter Globally Source: CReSIS and NASA Land area lost by 1-meter rise in sea level

23. Impact of 1-meter sea level rise: From Anthoff et al., 2006 An immediate and significant impact on economies and ecosystems worldwide

24. 59 cm. 22 cm.

25. What Have Glaciers and Ice Sheets been Doing?

26. Worldwide Glacier Retreat • Glaciers in all regions are now retreating • Retreat is accelerating

27. Direct observations tell us: GREENLAND ANTARCTICA  Ice sheets are changing fast

28. Ice Shelf Disintegration 2000 km2 of Larsen Ice Shelf disintegrated in 2 days. Source: T. Scambos Require >10,000 years to form Disintegrate in weeks

29. Consequence of Ice Shelf Loss up to 510% faster in 2 years up to 400% faster in 2 years (Scambos et al., 2004) Formerly buttressed glaciers accelerate

30. Summer Acceleration in Greenland Look in GoogleEarth Position Velocity Total Melt Melt Summer 10% increase in speed =1% increase in annual speed (from Zwally et al., 2002)

31. Accelerating Outlet Glaciers K J K H (Source: I. Joughin)

32. Rapid Retreat Jacobshavns Isbrae 5 years 60 years 40 years 50 years Kangerdlugssuaq Glacier Jacobshavns Isbrae

33. North and South Source: J.Zwally Source: W. Krabill The deepest outlet glaciers exiting into the ocean are responding most.

34. The most sophisticated ice-flow models can’t reproduce these behaviors

35. NO! maximum? “…but..flow rates could increase or decrease in the future.” “Larger values cannot be excluded…” “…understanding of these effects is too limited to assess their likelihood or provide a best estimate or an upper bound for sea level rise.”

36. When Models Don’t Work • Proxies • Analogs • More field work

37. Sea-Level History tells us: • Less ice in warmer climates • Ice sheets shrink faster than they grow • Sea level change is not smooth HIGH SEA LEVEL Less ice More ice LOW TEMPERATURE WARM COLD THEN NOW Time  Ice sheet dynamics matters But we don’t know the details

38. Sea level has gone up much faster • Relatively steady over past 6000 yrs (2 mm/yr.) • Periods of fast rise • Up to 20 times present rate • Can’t be due to melting alone • Ice flow dictates rapid sea level rise

39. Tidewater glaciers are a good analogue to predict ice sheet future Muir Glacier, Alaska 1941 2004 Large outlet glaciers are displaying classic “drastic retreat” traits similar to Alaskan tidewater glaciers 1971

40. Tidewater glaciers are a good analogue Columbia Glacier, Alaska • Tidewater glaciers slowly erode deep fjords • terminus rests on an extended, but shallow submarine moraine • Retreat into deep water initiates intense calving and rapid retreat • Columbia Glacier was last Alaskan tidewater glacier on extended moraine (in 1978) • Retreat began in 1980 • 15 km retreat by 2000 • 40 km retreat expected ?? 2000 1980 Source: USGS Retreat continues until bed rises above sea level

41. Helheim Glacier, Greenland Columbia Glacier, Alaska 2007 image (GoogleEarth) 1996 aerial photograph

42. Central region of Greenland is below sea level • Jacobshavns Isbrae occupies subglacial channel connected to central depression Russel Huff, Univ. of Colorado

43. Antarctica West Ant. East Ant. Nearly all of West Antarctica ice sheet and much of East Antarctica ice sheet rests on bed below sea level

44. Fingerprint of Collapse in Antarctica Pine Island, Thwaites and Smith Glaciers exhibit expected signs of collapsing: • Thinning increasing towards coast (satellite altimetry) • Flow acceleration (InSAR) • Retreat of grounding line (Landsat) • Calving of large icebergs (MODIS) Thinning rate Pine Island Gl. Thwaites Gl. Smith Gl. All observations made by satellite sensors. Most of this area has never been visited by humans.

45. PIG Ice Shelf Photo by C. Leight January 4, 2008

46. Our Hypothesis

47. Southern Ocean Circulation

48. Bringing the Heat (Source: A. Jenkins)

49. Amundsen Sea well suited to CDW upwelling Deep Ocean Continental Shelf Pine Island Gl. Ice Sheet TWG

50. Extreme Sub-Ice-Shelf Melt Rates Melt Rate (Rignot and Jacobs, 2002) Intense melt rates for small ocean vs. ice temperature differences