1. 1 The Evolution of the Recent Atmospheric Methane Budget Lori Bruhwiler, Ed Dlugokencky, Steve Montzka, Pieter Tans Earth System Research Laboratory Boulder, Colorado Elaine Matthews NASA Goddard Institute for Space Studies New York, NY

2. 2 CarbonTracker - CH 4

3. 3 CarbonTracker-CO 2

4. 4 Fluxes We Estimate: Terrestrial Biosphere Oceans Fluxes We “Know”: Fossil Fuels Photochemistry: None Measurement Sites ~100 Coal Production, Oil/Gas Leaks Animals, Waste, Rice,Wetlands Termites, Oceans,Soils, Others None Reaction with OH (and Cl) <100

5. 5 Co-Located Distributed and Point Sources (Natl. Geographic, June 08)

6. 6 Observed Global Growth Rate Methane could be approaching steady state (Dlugokencky et al., GRL, 2003) even though it is suspected that some sources are increasing. Why is growth slowing? What causes variability? What happened in 2007?

7. 7 Optimized 2001 Emissions: 526Tg/yr (Bergamaschi,2002) Coal30 (TgCH4/yr) Oil/Gas50 Enteric Fermentation/Manure100 Rice59 Biomass Burning32 Waste74 Wetlands174 Wild Animals5 Termites19 Soil-38 Oceans17 Coal30 (TgCH4/yr) Oil/Gas50 Enteric Fermentation/Manure100 Rice59 Biomass Burning32 Waste74 Wetlands174 Wild Animals5 Termites19 Soil-38 Oceans17

8. 88 Interannual Variability From Emission Processes

9. 9 WetlandsWetlands ~175 Tg/yr

10. 10 WetlandsWetlands Area: 5.6x10 6 km 2 (4% Global Land Surface) Boreal Wetlands: 50% of global wetland area, 25% CH 4 global wetland emission Temperature-Regulated Seasonal (Freeze, Thaw) High Organic Matter (Peat) Tropical/Subtropical Wetlands: 40% of global wetland area, 65% CH 4 wetland emission Precipitation-Regulated Seasonal (Flooding, Water Table Rise)

11. 11 Regression calculation used in TM5 :  Flux =   T +   P (  T - GISS Surface Temperature Analysis ) (  P - GPCC Global Precipitation) How well will it agree with atmospheric observations?

12. 12 FireFire ~30Tg/yr

13. 13 Biomass Burning Emissions: Global Fire Emissions Database (GFEDv2) Burned area/fire locations obtained from MODIS Vegetation and soil biomass obtained using the CASA Biosphere model Giglio et al., 2006 Transport the Emissions with TM5

14. 14 Observed CH 4 Growth Rate (ppb/yr) (Figure by K. Masarie)

15. 15 Observed CO Growth Rate (ppb/yr) (data: P. Novelli)

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18. 18 OCOC August 2007 mm/month Wetland Emission Module

19. 19 Tg CH 4 2007 Wetland Emissions(Annual Total) Eurasia: 8Tg N America: 3Tg

20. 20 Modeled and Observed CH 4 Anomalies Wetlands+Biomass Burning

21. 21 PermafrostDegradation?

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23. 2323 Interannual Variability From Chemical Loss Processes

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26. 26 But 2% is still ~10Tg! (Source: S. Montzka, ESRL)

27. 2727 Long-Term Trends

28. 28 Where Did It All Go?

29. 29 Coal Production (Source: BP)

30. 30 Simulated Methane from Coal Production

31. 31 Methane Gradients from Changes in Coal Emissions

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39. 39 Prototype CarbonTracker-CH 4 : Priors Bergamaschi et al. (2002) sources Large region inversion using network obs. Coal, Oil/Gas Enteric Fermentation, Wild Animals, Termites Rice, Wetlands, Biomass Burning Waste Soil Uptake, Oceans Photochemical Loss Repeating Seasonal Cycle, Optimized Using CH 3 CCl 3

40. 40 Prototype CarbonTracker-CH 4 : Inverse 121 parameters (Scalar Multipliers of Fluxes) Land:12 regions x 10 processes Ocean:1 regions Prior Uncertainty75% Sites83 Active sites 57 Surface sites 24 Aircraft profile locations 2 Observatories

41. 41 Coal Wetlands Waste

42. 4242 MLO Obs. Posterior ppb

43. 43 ConclusionsConclusions 1) We need to track the sources/sinks of atmospheric methane because we don’t understand its budget! 2) A prototype of CarbonTracker-CH 4 exists and is being evaluated. 3) Work is proceeding on developing/identifying improved models for prior fluxes. 4) CarbonTracker-CH4 could provide an early indication of methane release from destabilizing Arctic permafrost.