2. Where has all the Carbon Gone? Atmospheric oxygen, carbon fluxes and the implications for climate change. Mark Battle (Bowdoin College) Michael Bender (Princeton) Ralph Keeling (Scripps Institute of Oceanography) Pieter Tans (NOAA/CMDL) Jesse Bastide, Carrie Simonds, Blake Sturtevant, Becca Perry Bates College, 12/3/2004 Funding from: NSF, EPA, NOAA GCRP, BP-Amoco, Bowdoin College

3. Organizing Principle: 1 topic superficially

4. Organizing Principle: 1 topic superficially Several topics with vanishing content

5. Outline: Context: –Climate Change –CO 2 as an agent of change Where does the CO 2 go? How does O 2 tell us this? The basic answer A more refined answer Related work in progress

6. Why should we care about climate change? “An increasing body of observations gives a collective picture of a warming world…” “…most of the warming observed over the last 50 years is attributable to human activities.” “ Anthropogenic climate change will persist for many centuries.” “Emissions of greenhouse gases… continue to alter the atmosphere in ways that are expected to affect the climate.” IPCC, 2001

7. Why CO 2 ? IPCC, 2001

8. Why CO 2 ? “ The atmospheric concentration of CO 2 has increased by 31% since 1750. The present CO 2 concentration has not been exceeded during the past 420,000 years and likely not during the past 20 million years. The current rate of increase is unprecedented during at least the past 20,000 years.” IPCC, 2001

9. Where does anthropogenic CO 2 end up?

10. Recap: The planet is warming Human activities are to blame CO 2 is the primary culprit Future buildup depends on Atm vs. Land vs. Ocean Land/Ocean partition is tough to measure

11. The link between O 2 and CO 2  CO 2 = Land biota + Industry + Ocean  O 2 = Land biota + Industry

12. O 2 /N 2 changes are small  O 2 /N 2 per meg  (O 2 /N 2sa – O 2 /N 2st )/(O 2 /N 2st ) x10 6 1 per meg = 0.0001% 1 GtC = 10 9 metric tons C = 10 15 g C 1 GtC from FF  3.2 per meg  O 2 /N 2

13. Graphically…

18. The Princeton cooperative flask sampling network

19. Ships of opportunity

20. Research Vessels

21. Automatic Air Recovery Device Version ARK-5 In use at: Cape Grim Ka’imimoana Samoa Barrow Sable Macquarie Princeton

22. Our measurement technique: IRMS (Finnigan Delta+XL) 32/28 and 40/28 (as well as 44/28 and 29/28) Custom dual-inlet system Indirect comparison with standards For more details: Bender et al., In review

23. Battle et al., Science 2000

24. 1991 – 1997 Land sink = 1.4 ± 0.8 GtC/yr Ocean sink = 2.0 ± 0.6 GtC/yr Battle et al. Science 2000 (2467-2470)

25. Is it really that simple?  O 2 = Land biota + Industry + Ocean  CO 2 = Land biota + Industry + Ocean HeatBiology

28. Longer records from more sites…

29. Longer records from more sites + Solubility correction + Stratification correction  Ocean uptake = 1.7 ± 0.5 Net Land uptake = 1.0 ± 0.6 (1994 – 2002) Bender et al. In review

30. Summary The climate is changing Anthropogenic CO 2 is to blame O 2 can tell us about the fate of CO 2 The O 2 -CO 2 linkage isn’t trivial We find a substantial terrestrial sink (volatile?) But the story doesn’t end here…

31. Measurements of O 2 and CO 2  O 2 = Land biota + Industry  CO 2 = Land biota + Industry + Ocean f land & f ocean > 0 for carbon storage by land and ocean

32. Measurements of O 2 and CO 2  O 2 = Land biota + Industry  CO 2 = Land biota + Industry + Ocean f land & f ocean > 0 for carbon storage by land and ocean

33. Determining the O 2 :CO 2 stoichiometry for the land biota

34. What else might we learn?  O 2 = Land biota + Industry  CO 2 = Land biota + Industry + Ocean f land & f ocean > 0 for carbon storage by land and ocean

35. APO: an ocean-only “tracer” APO  O 2observed + 1.1 CO 2observed (I have ignored units)

36. APO: an ocean-only “tracer” APO  O 2observed + 1.1 CO 2observed (I have ignored units) So what?

37. Ocean biology and circulation

38. fluxes of CO 2 and O 2

39. Ocean biology and circulation fluxes of CO 2 and O 2 atmospheric transport

40. Ocean biology and circulation fluxes of CO 2 and O 2 atmospheric transport atmospheric composition at observing stations

41. fluxes of CO 2 and O 2 atmospheric transport atmospheric composition at observing stations

42. APO measurements + good flux estimates  rigorous test of atmospheric transport

43. Is this different from other models?