1. Limits to Adaptation Ocean acidification Congressional Briefing 9 November 2009 Ken Caldeira Carnegie Institution & Stanford University kcaldeira@carnegie.stanford.edu

2. Rain, galoshes, and limits to adaptation To avoid getting wet, you want to bring an umbrella To avoid climate risk, you want to reduce carbon dioxide emissions Kasmira,2009 But to keep your feet dry, you might still need galoshes To diminish damage from the climate change you cant avoid, you want to improve adaptive resilience Just wearing galoshes is not enough emissions reduction adaptation

3. Ischia, Italy Map created by Norman Einstein

4. CO 2 dissolving shells and skeletons Hall-Spencer / BBC High CO 2 = Invasive grasses Low CO 2 = Native shellfish Thanks, Jason Hall-Spencer

5. Chemistry of ocean acidification

6. Formation of calcium carbonate shells and skeletons CO 3 2- C O O O Ca Ca 2+ (dissolved) H H O H2OH2O H C O O O HCO 3 - C O O O CO 3 2-

7. Formation of calcium carbonate shells and skeletons CO 3 2- C O O O Ca Ca 2+ (dissolved) H H O H2OH2O H C O O O HCO 3 - C O O O CO 3 2-

8. Formation of calcium carbonate shells and skeletons CO 3 2- C O O O Ca Ca 2+ (dissolved) H H O H2OH2O H C O O O HCO 3 - C O O O CO 3 2-

9. Formation of calcium carbonate shells and skeletons C O O O Ca CaCO 3 (solid) H H O H2OH2O H C O O O HCO 3 - C O O O CO 3 2-

10. Water, dissolved carbon, and shells and skeletons CaCO 3 (solid) C O O O Ca H H O H2OH2O H C O O O HCO 3 - C O O O CO 3 2-

11. Addition of CO 2 CaCO 3 (solid) C O O O Ca H H O H2OH2O H C O O O HCO 3 - C O O O CO 3 2- C OO CO 2

12. Formation of carbonic acid C O O O Ca H C O O O HCO 3 - C O O O CO 3 2- HH C O O O H 2 CO 3 CaCO 3 (solid)

13. Increasing ocean acidity C O O O Ca H C O O O HCO 3 - C O O O CO 3 2- H C O O O HCO 3 - H H+H+ CaCO 3 (solid)

14. Increasing ocean acidity C O O O Ca H C O O O HCO 3 - C O O O CO 3 2- H C O O O HCO 3 - H H+H+ CaCO 3 (solid)

15. Increasing ocean acidity C O O O Ca H C O O O HCO 3 - C O O O CO 3 2- H C O O O HCO 3 - H H+H+ CaCO 3 (solid)

16. Increasing ocean acidity CaCO 3 (solid) C O O O Ca H C O O O HCO 3 - C O O O CO 3 2- H C O O O HCO 3 - H H+H+

17. Attacking a building block for shells and skeletons C O O O Ca H C O O O HCO 3 - C O O O CO 3 2- H C O O O HCO 3 - H H+H+ CaCO 3 (solid)

18. H Attacking a building block for shells and skeletons C O O O Ca H C O O O HCO 3 - C O O O H C O O O CaCO 3 (solid)

19. H Dissolving shells and skeletons CO 3 2- C O O O H C O O O HCO 3 - C O O O H C O O O Ca Ca 2+ (dissolved)

20. H Dissolving shells and skeletons CO 3 2- C O O O H C O O O HCO 3 - C O O O H C O O O Ca Ca 2+ (dissolved)

21. H Dissolving shells and skeletons CO 3 2- C O O O H C O O O HCO 3 - C O O O H C O O O Ca Ca 2+ (dissolved)

23. Lizard Island Expedition September 2008

24. We measured of coral skeletal growth rates 40% lower than in the late 1970s

25. Distribution of corals and ocean acidification

26. 012345 CorrosiveOptimal Ω Aragonite Carbon dioxide level, Coral reef distribution, and chemical conditions helping drive reef formation Cao and Caldeira, 2008

27. 012345 CorrosiveOptimal Ω Aragonite Cao and Caldeira, 2008 Carbon dioxide level, Coral reef distribution, and chemical conditions helping drive reef formation

28. 012345 CorrosiveOptimal Ω Aragonite Cao and Caldeira, 2008 Carbon dioxide level, Coral reef distribution, and chemical conditions helping drive reef formation

29. 012345 CorrosiveOptimal Ω Aragonite Cao and Caldeira, 2008 Carbon dioxide level, Coral reef distribution, and chemical conditions helping drive reef formation

30. 012345 CorrosiveOptimal Ω Aragonite Cao and Caldeira, 2008 Carbon dioxide level, Coral reef distribution, and chemical conditions helping drive reef formation

31. 012345 CorrosiveOptimal Ω Aragonite Cao and Caldeira, 2008 Carbon dioxide level, Coral reef distribution, and chemical conditions helping drive reef formation

33. Rain, galoshes, and limits to adaptation Kasmira,2009 emissions reduction adaptation Adaptation is important, but it is not a substitute for emissions reduction We need an umbrella and galoshes

34. Main points Few and limited options for adaptation to acidification –Adaptive capacity of ecosystems can be increased by reducing other stresses on our ocean environment (overfishing, land-based pollution, habitat loss, etc) –Management and engineering solutions appear to be feasible only in a few isolated cases To protect our coastal and ocean environments, we need to greatly reduce our CO 2 emissions soon