1. Using a climate change story to teach about large lake processes Jay Austin Associate Professor Large Lakes Observatory /Department of Physics University of Minnesota Duluth Teaching Climate Change: Lessons from the Past 20 June, 2012

3. The Past and Present The Past: What sorts of records allow us to reliably look into the past? The Present: How do we understand how Lake Superior is changing right now?

6. Sault Ste. Marie, 1906-2006 (“the past”)

7. SSM, July-September avg.

9. Global AT average

11. Comparing SSM to globe

12. ~0.1C/yr

13. Regional Air Temperature Anomaly ~0.06C/yr

14. NOAA’s NDBC buoys (“The Present”) Three buoys in Lake Superior 1979-Present April-November AT,WT, WS/WD (also buoys in other lakes)

15. 45006 * 45006 * 45001 * 45004

16. NDBC 45001 (Central) Water Temperature, July-Sep ~0.1C/yr

17. NDBC 45001 (Central) Water Temperature ~0.12C/yr (Max. Temperatures)

18. Lakes around the world

19. Freshwater Density

20. Summer stratification Warm water overlies cooler water- surface layer can be relatively thin (~10-30m)

21. Winter Stratification Cool water overlies warmer water- surface layer very deep- often comprises entire water column

23. Start of Stratified season

24. Central Buoy WT, 2006 Slow warming Summer Overturn Rapid warming Max temp., mid August Fall Cooling Buoy recovered

25. Two extremes- 1996 (cold) and 1998 (warm) 1998 1996

26. Ice Cover in Decline

28. Magnuson et al. 2000 Formation dates Breakup dates

29. Magnuson et al., 2000

30. Howk 2008

31. Summer Overturn date depends on last winter’s ice cover

32. Summer Water Temperature depends on last winter’s ice cover (1998)

33. Length of season 12d earlier/century 10d later/century 22d longer/century

34. Acknowledgements!