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)

High-resolution inversion of N American methane emissions using GOSAT satellite observations GOSAT observations, 2009-2011 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]

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 2009-2011 GOSAT anthropogenic Poor representation of source types in EDGAR prevents attribution of inversion results: need gridded version of EPA inventory! Turner et al. [2015]

Difference between inversions of US methane emissions: Interpretation as time series would imply 30% increase in US emissions for 2004-2011 but EPA inventory shows no trend 5.4% a-1 Turner Miller Wecht EPA inventory Turner et al., submitted

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 (2002-2014) 6.0% a-1 (2004-2011) Turner et al., submitted

GOSAT shows rising methane emissions across midwestern US 2010-2014 trend in difference between nadir (land) and glint (Pacific) methane columns; black dots indicate significant (>95%) trends on 4ox4o grid 2010-2014 trend of 7.0% a-1 over CONUS – but source attribution is unclear Turner et al., submitted

Global implications Trend in global atmospheric methane E. Dlugokencky, NOAA Methane trend since 2006 implies an increase in global emissions of 3.4-4.4 Tg a-1 [Kirschke et al., 2013] We find that US emissions during that period grew by 3-7% a-1 or 1.1-2.5 Tg a-1. Rising US emissions could have accounted for 30-60% of the global rise in methane Turner et al., submitted

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]

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.

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.

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

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

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

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.

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.

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.

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.

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.

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.

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.

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

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 2009-2012 emissions uncertainty factor Bloom et al., in prep - see poster!

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 2009-2014 inversion of methane fluxes in N America with GOSAT Use inversion results to improve inventories, working with EPA for US Diagnose and interpret trends