1. Geophysical Fluid Dynamics Laboratory Review June 30 - July 2, 2009 Geophysical Fluid Dynamics Laboratory Review June 30 - July 2, 2009

2. Geophysical Fluid Dynamics Laboratory Review June 30 - July 2, 2009 Climate and Air Quality Presented by Arlene Fiore Presented by Arlene Fiore

3. 3 ~25% of global anthropogenic emissions at cost-savings / low-cost IEA [2003] for 5 industrial sectors 10% of anth. emissions 20% of anth. emissions 020406080100120 Methane emission reduction potential (Mton CH 4 yr -1 ) (industrialized nations) (West and Fiore, 2005) Cost-saving Cost-effective All identified METHANE CONTROL OPTIONS Addressing air quality and climate via methane emission controls: A viable option?

4. 4  Robust result across models Range across 18 models (Results from TF HTAP model intercomparison; Fiore et al., 2009) N. Amer. Europe E. Asia S. Asia  Intercontinental emission controls: CH 4 ≈ NO x +NMVOC+CO  Domestic emission controls: NO x +NMVOC+CO more effective -20% Foreign Anthrop. Emissions -20% Domestic Anthrop. Emissions Decreasing methane lowers global surface O 3 background

5. 5 BASE OZONE METHANE Net Forcing CH 4 =700 ppb (W m -2 ) CH 4 CONTROL Cost-effective controls prevent increase in O 3 > 70 ppbv in 2030 relative to 2005 in Europe Percentage of model grid-cell days where surface ozone (MDA8) > 70 ppbv (Fiore et al., 2008) BASE 2005 BASE 2030 CH 4 CONTROL CH 4 =700 ppb CLIMATEAIR QUALITY Methane emission reductions are applied to BASE emission scenario (2005 to 2030 full-chemistry transient simulations in MOZART-2) Benefits from CH 4 controls to climate and air quality: Decreased radiative forcing and high-O 3 events

6. 6 6 OBSERVED BASE (constant emis.) ANTH (time-varying) ANTH+BIO (time-varying) (Fiore et al., 2006) Global mean surface methane (ppb)  T(+0.3K) +=  OH(+1.2%) BASE Contributions to change in methane lifetime from 1991-1995 to 2000-2004 in BASE Decrease in methane lifetime (years) Climate sensitivity: Small increases in temp. and OH shorten the methane lifetime

7. 7 CLIMATE AND AIR QUALITY BENEFITS FROM CH 4 CONTROL Decreased hemispheric background O 3 (robust across models) Complementary to NO x, NMVOC controls Independent of reduction location (but depends on NO x ) IMPACT OF CHANGING CLIMATE ON METHANE TRENDS ? 1990 to 2004 model trend driven by increasing T, OH Trends in global lightning activity? Other potential climate feedbacks (on sources and sinks) (Fiore et al., 2002, 2006; West and Fiore, 2005; Fiore et al., 2008, 2009) Summary: Connecting climate and air quality via O 3 & CH 4

8. 8 20-year AM3 simulations with annually-invariant emissions of ozone and aerosol precursors (except for lightning NOx), to isolate role of climate change 1. Present Day Simulation (“1990s”): observed SSTs and sea ice (1981-2000 mean) 2. Future Simulation (“A1B 2090s”): observed SSTs and sea ice + average 2081-2100 changes from 19 IPCC AR-4 models CHANGES IN SUMMER (JJA) MEAN DAILY MAX 8-HOUR OZONE NEW DIRECTION: Impact of Future Changes in Climate on Air Quality

9. Geophysical Fluid Dynamics Laboratory Review June 30 - July 2, 2009 Geophysical Fluid Dynamics Laboratory Review June 30 - July 2, 2009