1. What do Paleoclimate. records tell us about. WAIS stability? What Do West Antarctic Ice Cores Say About Rapid Ice Flow? Ken Taylor Richard Alley Ed Brook Howard Conway Jeff Severinghaus Paul Mayewski Jim White

2. Byrd vs SDM White & Brook Warmer Colder

3. Byrd vs SDM White & Brook Warmer Colder

4. Byrd vs SDM White & Brook 15 ka 22 ka Warmer Colder

5. Byrd vs SDM White & Brook Warmer Colder

6. Gas records kkks Must be local change at Siple Dome because: 1) Change does not show up at Byrd 2) Proxies of distant climate (D excess and chemistry) do not show significant changes Siple Dome Records

7. Gas records kkks Must be local change at Siple Dome because: 1) Change does not show up at Byrd 2) Proxies of distant climate (D excess and chemistry) do not show significant changes Siple Dome Records Disrupted stratigraphy

8. Regional Climate Change: Would see something at Byrd and in other climate proxies from SDM.

9. Regional Climate Change: Would see something at Byrd and in other climate proxies from SDM. Mishandling of Core: Gas record/Deuterium record offset is correct

10. Regional Climate Change: Would see something at Byrd and in other climate proxies from SDM. Mishandling of Core: Gas record/Deuterium record offset is correct Folded Stratigraphy: No suitable ice to fold into record

11. Regional Climate Change: Would see something at Byrd and in other climate proxies from SDM. Mishandling of Core: Gas record/Deuterium record offset is correct Folded Stratigraphy: No suitable ice to fold into record Ice Flow Overrode Siple Dome Change in record is too abrupt No other ice with right characterisitics

12. Regional Climate Change: Would see something at Byrd and in other climate proxies from SDM. Mishandling of Core: Gas record/Deuterium record offset is correct Folded Stratigraphy: No suitable ice to fold into record Ice Flow Overrode Siple Dome Change in record is too abrupt

13. Interpretation 1: Elevation of Siple Dome Changed  Lapse Rate 22 ka B.P. 6 o C warming, ~200 years 600 m elevation decrease at SDM 15 ka B.P. 3.5 o C warming < 1,000? years 350 m elevation decrease at SDM Ice Flow Modeling: Rapid 350 m decrease of Siple Dome at 15 ka ( Price et. al., 2007) Atmospheric Modeling: Elevation of ice streams has large influence on temperature at Summit of Siple Dome (Monaghan & Bromwich, 2006)

14. Interpretation 1: Elevation of Siple Dome Changed  Lapse Rate 22 ka B.P. 6 o C warming, ~200 years 600 m elevation decrease at SDM 15 ka B.P. 3.5 o C warming < 1,000? years 350 m elevation decrease at SDM Ice Flow Modeling: Rapid 350 m decrease of Siple Dome at 15 ka ( Price et. al., 2007) Atmospheric Modeling: Elevation of ice streams has large influence on temperature at Summit of Siple Dome (Monaghan & Bromwich, 2006)

15. Interpretation 2: Elevation of Ice Streams Changed  Air Flow Changed Atmospheric Modeling: Elevation of ice streams has large influence on temperature at Summit of Siple Dome (Monaghan & Bromwich, 2006) Ice Sheet Model: Siple Dome was a bump (Dave Pollard) SDM BYRD Current situation Paleo situation

16. Some combination of: 1) Changes in SDM surface elevation. (lapse rate) 2) Changes in ice stream elevation. (air flow patterns/katabatic winds) At 15 ka and 22 ka there were large and rapid drawn downs of ice on the Siple Coast.

17. What caused ice draw down? Sea level rise Sub-ice flood Ice shelf collapse Ice stream internal dynamics

18. ocean Explaination Siple: White et al Sea Level 12 m Yokoyama 16 m Hanebuth The Siple Dome events precede the step increases in sea level.

19. What caused ice draw down ? Sea level rise Sub-ice flood Ice shelf collapse Ice stream internal dynamics

20. ` Eastern Ross Sea Mosola & Anderson, 2006 Slope Gullies Sub-ice water system

21. What caused ice draw down? Sea level rise Sub-ice flood Ice shelf collapse Ice stream internal dynamics

22. MAP SHOWING Tdome, SDM, BYRD, Moulton, OCEAM COres Roosevelt Island BYRD Ross Ice Shelf Siple Dome http://lima.usgs.gov/access.php

23. MAP SHOWING Tdome, SDM, BYRD, Moulton, OCEAM COres Roosevelt Island BYRD Ross Ice Shelf Siple Dome http://lima.usgs.gov/access.php

24. Water Temperature Ice Shelf Thickness Bathymetry Siple and Shirase Coasts are most vulnerable David Holland

25. Water Temperature Ice Shelf Thickness Bathymetry Siple and Shirase Coasts are most vulnerable David Holland

26. Water Temperature Ice Shelf Thickness Bathymetry Siple and Shirase Coasts are most vulnerable David Holland

27. Water Temperature Ice Shelf Thickness Bathymetry Siple and Shirase Coasts are most vulnerable David Holland

28. ` Eastern Ross Sea Mosola & Anderson, 2006 Iceberg furrows at 650 m No sub-ice shelf deposits Rapid retreat of grounded ice

29. MAP SHOWING Tdome, SDM, BYRD, Moulton, OCEAM COres Roosevelt Island BYRD Ross Ice Shelf Siple Dome http://lima.usgs.gov/access.php

30. What caused ice draw down? Sea level rise Sub-ice flood Ice shelf collapse Ice stream internal dynamics

31. Siple Coast ice had large and rapid changes at 15 ka and 22 ka Basal flooding Break up of a portion of the Ross Ice Shelf Ice stream internal dynamics

33. Amanda Mosola & John Anderson Andy Monaghan, Dave Brom

34. * Ignore this age; the simulation is for 15 ka From dave pollard pollard@essc.psu.edu