1. Methane emission trends in the United States and new bottom-up inventories for flux inversions
Daniel J. Jacob
with
Bram Maasakkers, Jianxiong Sheng, Melissa Sulprizio, Alex Turner (Harvard)
Anthony Bloom, Kevin Bowman (JPL)
Mark DeFigueireido, Mausami Desai, Cate Hight, Leif Hockstad, Bill Irving,
Melissa Weitz, Tom Wirth (EPA)
Steven Hamburg, Robert Harris, Daniel Zavala-Araiza (EDF)

2. High-resolution inversion of N American methane emissions using GOSAT satellite observations
GOSAT observations,
Dynamic
boundary
conditions
Analytical inversion
with 369 Gaussians
Adjoint-based inversion
at 4ox5o resolution
correction factors to EDGAR v4.2 + LPJ prior
Turner et al. [2015]

3. need gridded version of EPA inventory!
Methane emissions in US: comparison to previous studies, attribution to source types
This work
Turner
Ranges from
prior error
assumptions
EPA
EDGAR
EDGAR
Total US
2004
SCIAMACHY
2007
surface,
aircraft
GOSAT
anthropogenic
Poor representation of source types in EDGAR prevents attribution of inversion results:
need gridded version of EPA inventory!
Turner et al. [2015]

4. Difference between inversions of US methane emissions:
Interpretation as time series would imply 30% increase in US emissions for
but EPA inventory shows no trend
5.4% a-1
Turner
Miller
Wecht
EPA
inventory
Turner et al., submitted

5. Long-term NOAA data from Oklahoma show rise vs
Long-term NOAA data from Oklahoma show rise vs. background over past decade
3.6% a-1 ( )
6.0% a-1 ( )
Turner et al., submitted

6. GOSAT shows rising methane emissions across midwestern US
trend in difference between nadir (land) and glint (Pacific) methane columns;
black dots indicate significant (>95%) trends on 4ox4o grid
trend of 7.0% a-1 over CONUS – but source attribution is unclear
Turner et al., submitted

7. Global implications Trend in global atmospheric methane
E. Dlugokencky, NOAA
Methane trend since 2006 implies an increase in global emissions of Tg a-1 [Kirschke et al., 2013]
We find that US emissions during that period grew by 3-7% a-1 or Tg a-1.
Rising US emissions could have accounted for 30-60% of the global rise in methane
Turner et al., submitted

8. EPA national methane emission inventory (Tg a-1, 2012)
EPA inventory reported to UNFCCC includes best process-based knowledge of sources but is only available as national totals by source category
Other 1.4
Waste 5.5
wastewater (0.6)
enteric fermentation (6.7)
landfills (4.9)
Agriculture 9.6
distribution
(1.2)
rice (0.4)
transmission
(2.1)
processing (0.9)
production (2.0)
offshore
(0.6)
onshore
(0.9)
Natural gas 6.2
Coal mines 3.2
Petroleum 1.5
US EPA [2014]

9. Constructing a gridded version of the EPA national inventory
0.1ox0.1o gridded information
Greenhouse Gas Reporting Program: large point sources
(oil/gas/coal, waste)
report emissions to EPA
Additional data for locations
of oil/gas wells, stations, pipelines, coal mines, landfills, wastewater plants…
Data for livestock, manure management, rice at sub-county level (USDA + EPA)
Process-level emission factors including monthly variation
Reconciliation to EPA state/national totals
for each source subcategory
Gridded version of EPA inventory
0.1ox0.1o monthly resolution
detailed breakdown by source types
Includes error characterization
to be hosted/distributed by EPA
Maasakkers et al., in prep.

10. Gridded EPA inventory of US methane emissions: a snapshot of results
2012: Livestock Rice Gas production Coal mines
Inventory includes detailed breakdown by source (sub)categories
Maasakkers et al., in prep.

11. Gridded EPA inventory of methane emissions (2012)
Maasakkers et al., in prep.

12. EDGARv4.2 inventory (2010)
Maasakkers et al., in prep.

13. Difference EPA – EDGARv4.2
Maasakkers et al., in prep.

14. Methane source pattern correlations in South-Central US
Livestock Oil & Gas Waste
EPA
EDGARv4.2
1414
EDGAR O&G is strongly correlated to waste; gas production is aliased to agriculture
EPA has much better source separation – no spatial correlation at any scale
Maasakkers et al., in prep.

15. Gridded version of ICF national inventory
for Canadian oil and gas emissions (2013)
2.32
Tg CH4 a-1
Gas transmission 0.29
Gas distribution 0.05
Gas production
1.46
Oil production 0.52
Sheng et al., in prep.

16. Emissions from gas production & processing
1.46
Tg CH4 a-1
Gas transmission 0.29
Gas distribution 0.05
Gas production
1.46
Oil production 0.52
Sheng et al., in prep.

17. Emissions from oil production
0.52
Tg CH4 a-1
Gas transmission 0.29
Gas distribution 0.05
Gas production
1.46
Oil production 0.52
Sheng et al., in prep.

18. Emissions from gas transmission and LNG import
0.29
Tg CH4 a-1
Gas transmission 0.29
Gas distribution 0.05
Gas production
1.46
Oil production 0.52
Sheng et al., in prep.

19. Methane emissions from gas distribution
0.05
Tg CH4 a-1
Gas transmission 0.29
Gas distribution 0.05
Gas production
1.46
Oil production 0.52
Sheng et al., in prep.

20. Gridded version of Mexican National Emission Inventory for oil and gas (2013)
1.11 Tg CH4 a-1
Gas production
0.28
Oil production
0.57
Gas processing 0.09
Gas transmission 0.06
Gas distribution 0.11
Sheng et al., in prep.

21. Differences with EDGARv4.2
EDGAR largely misses emissions from oil/gas production,
overestimates emissions in urban areas
Sheng et al., in prep.

22. New bottom-up inventory of wetlands emissions including detailed error characterization
Ensemble approach using SWAMPS satellite inundation data,
8 MsTMIP terrestrial carbon models, 3 temperature dependences
emissions uncertainty factor
Bloom et al., in prep - see poster!

23. What now?
Publish and release US, Canadian, Mexican, wetlands inventories
US emissions to be distributed through EPA
Post-2012 emissions are straightforward to generate
Conduct inversion of methane fluxes in N America with GOSAT
Use inversion results to improve inventories, working with EPA for US
Diagnose and interpret trends