* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download NASA Air Quality Applied Sciences Team (AQAST)
Climatic Research Unit documents wikipedia , lookup
Media coverage of global warming wikipedia , lookup
General circulation model wikipedia , lookup
Instrumental temperature record wikipedia , lookup
Climate engineering wikipedia , lookup
Climate change and agriculture wikipedia , lookup
German Climate Action Plan 2050 wikipedia , lookup
Climate governance wikipedia , lookup
Economics of global warming wikipedia , lookup
Scientific opinion on climate change wikipedia , lookup
Citizens' Climate Lobby wikipedia , lookup
Climate change mitigation wikipedia , lookup
Economics of climate change mitigation wikipedia , lookup
Public opinion on global warming wikipedia , lookup
Effects of global warming on humans wikipedia , lookup
United Nations Climate Change conference wikipedia , lookup
Climate change, industry and society wikipedia , lookup
2009 United Nations Climate Change Conference wikipedia , lookup
Views on the Kyoto Protocol wikipedia , lookup
Low-carbon economy wikipedia , lookup
Surveys of scientists' views on climate change wikipedia , lookup
Global warming wikipedia , lookup
Attribution of recent climate change wikipedia , lookup
Climate sensitivity wikipedia , lookup
Climate change and poverty wikipedia , lookup
Solar radiation management wikipedia , lookup
Mitigation of global warming in Australia wikipedia , lookup
Effects of global warming on Australia wikipedia , lookup
Politics of global warming wikipedia , lookup
Climate change in New Zealand wikipedia , lookup
Climate change in the United States wikipedia , lookup
United Nations Framework Convention on Climate Change wikipedia , lookup
Business action on climate change wikipedia , lookup
Carbon Pollution Reduction Scheme wikipedia , lookup
US methane emissions and relevance for climate policy Daniel J. Jacob with Alexander J. Turner, J.D. (Bram) Maasakkers Supported by the NASA Carbon Monitoring System “ The Administration is announcing a new goal to cut methane emissions from the oil and gas sector by 40 – 45 percent from 2012 levels by 2025” [President’s Updated Climate Action Plan, 2015] Gorillas and chimpanzees of climate change CO2: the 800-lbs gorilla Methane and black carbon: the chimps Do we care about the chimps? Radiative forcing of climate change Solar flux Fin Terrestrial flux Fout =σ T 4 • Global radiative equilibrium: Fin = Fout • Perturb greenhouse gases or aerosols radiative forcing F = Fin - Fout • Global equilibrium surface temperature response: To ~ F Radiative forcing referenced to emissions, 1750-2011 • Radiative forcing from methane emissions is 0.97 W m-2, compared to 1.68 W m-2 for CO2 • Radiative forcing from black carbon aerosol (BC) is 0.65 W m-2, highly uncertain • Together methane and BC have radiative forcing comparable to CO2 they have made comparable contribution to past climate change • But atmospheric lifetimes of methane (10 years) and BC (~1 week) are shorter than CO2 (> 100 years) • What does that mean for priorities in controlling future emissions? [IPCC, 2014] Climate policy metrics consider the integrated future impact of a pulse unit emission of a radiative forcing agent Inject 1 kg of agent X at time t = 0 Concentration C(t) from pulse time Impact from pulse = f(C(t)) time Discount rate Climate metric = 0 time (impact)(discount rate)dt …usually normalized to CO2 Standard IPCC metric: Global Warming Potential (GWP) Integrated radiative forcing over time horizon [0, H] Radiative forcing F vs. time for pulse unit emission of X at t = 0 CO2 methane BC H AGWP(X) ΔFX (t )dt 0 GWP(X) AGWP(X) AGWP(CO2 ) Discount rate: step function H time IPCC [2014] GWP for methane vs. chosen time horizon: 28 for H = 100 years 1 Tg CH4 = 28 Tg CO2 (eq) GWP is easy to compute, but it does not correspond to any physical impact Towards a temperature-based climate metric Cancun UN Climate Change Conference: hold global surface temperature change to less than 2oC above pre-industrial levels Intent is to avoid catastrophic climate change Global temperature potential (GTP) metric introduced by IPCC AR5 Global mean surface temperature change at t = H CO2 methane BC GTP ( X ) Temperature change vs. time for pulse unit emission at t = 0 ΔTo , X (H ) ΔTo ,CO 2 (H ) Discount rate: Dirac function H time IPCC [2014] Temperature response to actual 2008 emissions taken as a 1-year pulse Methane as important as CO2 for 10-year horizon, unimportant for 100-year horizon Why does methane cause only a short-term temperature response? Fin Fout To To t<0 t=0 climate equilibrium emission pulse F = 0 F > 0 To + To t = 20 years climate response F < 0 To t = 100 years back to original equilibrium F = 0 Implication of GTP-based policy for near-term climate forcers Aiming to optimize for a maximum temperature change on a 100-year horizon: GTP potential Right now we’ll just worry about CO2. But in 70 years please start acting on methane, and in 95 years go all after black carbon, baby! Sole focus on temperature change over long-term horizon sacrifices immediate climate emergencies No summer Arctic sea ice in 20 years? More hurricane Sandys? Methane and BC should be part of climate policy … but for reasons totally different than CO2 • It addresses climate change on time scales of decades – which we care about • It offers decadal-scale results for accountability of climate policy • It has important air quality co-benefits • It is an alternative to geoengineering by aerosols • Reducing methane emissions makes money • BC has additional regional, hydrological climate impacts Global and US inventories of methane emissions (2012) Other: 30 Global: 540 Tg a-1 Waste: 60 Wetlands: 160 Coal: 50 Fires: 20 Oil/Gas: 70 Livestock: 110 Rice: 40 Contiguous US: 33 Tg a-1 1.1 5.6 5.9 0.1 2.9 9.2 US is second oil/gas source after Russia according to UNFCCC 7.7 0.4 EDGAR4.2 and EPA greenhouse gas inventories Satellite observations of methane Instruments: SCIAMACHY (2002-2005), GOSAT (2009-), TROPOMI (2016 launch) Methane column mixing ratio Turner et al. [2015] Satellite observations of methane Instruments: SCIAMACHY (2002-2005), GOSAT (2009-), TROPOMI (2016 launch) Methane column mixing ratio Turner et al. [2015] “Top-down” constraints on emissions from satellite data Satellite observations of methane concentrations Chemical transport model Prior “bottom-up”inventory (EDGAR + wetlands) Emissions Concentrations Inverse Optimal estimation verification Optimized “top=down” inventory Aircraft and surface observations Correction factors to bottom-up EDGAR inventory • CONUS anthropogenic emission of 40-43 Tg a-1 vs. EPA value of 27 Tg a-1 • Is the underestimate in livestock or oil/gas emissions or both? Turner et al. [2015] Optimized top-down inventory • CONUS anthropogenic emission of 40-43 Tg a-1 vs. EPA value of 27 Tg a-1 • Is the underestimate in livestock or oil/gas emissions or both? Turner et al. [2015] Attribution of emission correction to oil/gas or livestock is complicated by uncertainty in location, spatial overlap • Oil/gas fields and cattle often share quarters • Gas emissions occur at exploration, production, processing, transmission, distribution Eagle Ford Shale, Texas EDGAR inventory oil/gas source pattern likely overemphasizes distribution vs. production Turner et al. [2015] Constructing a gridded version of the EPA national inventory Best process-based knowledge of sources, granular representation of processes, national inventory reported to the UNFCCC Large point sources (oil/gas/coal, waste) reporting emissions to EPA GIS data for location of wells, pipelines, coal mines,… National bottom-up US inventory of methane emissions at 0.1ox0.1o monthly resolution Livestock and rice data at sub-county level Process-level emission factors including seasonal variation J.D. Maasakkers (in prep.) with M. Weitz, T. Wirth, C. Hight, M. DeFiguereido [EPA] New EPA-based gridded emission inventory: natural gas production J.D. Maasakkers (in prep.) Natural gas processing New EPA-based gridded emission inventory: natural gas production + processing J.D. Maasakkers (in prep.) Natural gas transmission New EPA-based gridded emission inventory: natural gas production + processing + transmission J.D. Maasakkers (in prep.) Total EPA-based natural gas:gridded production + processing + transmission + distribution New emission inventory: natural gas production + processing + transmission + distribution J.D. Maasakkers (in prep.) Difference with EDGAR Using the EPA gridded emission inventory as prior will considerably increase The quality of information from inverse modeling estimates J.D. Maasakkers (in prep.)