1. Predicted change in global secondary organic aerosol concentrations in response to future climate, emissions, and land-use change Colette L. Heald NOAA Climate and Global Change Postdoctoral Fellow University of California, Berkeley (heald@atmos.berkeley.edu) Daven Henze, Larry Horowitz, Johannes Feddema, Jean-Francois Lamarque, Alex Guenther, Peter Hess, Francis Vitt, Allen Goldstein, Inez Fung, John Seinfeld International Union of Geodesy and Geophysics July 9, 2007

2. ORGANIC CARBON AEROSOL Semi- Volatiles Oxidation by OH, O 3, NO 3 Direct Emission Fossil Fuel Biomass Burning Monoterpenes Sesquiterpenes Partitioning (non-linear) Aromatics ANTHROPOGENIC SOURCESBIOGENIC SOURCES Isoprene S econdary O rganic A erosol P rimary O rganic A erosol

3. WHY WE SHOULDN’T FOCUS EXCLUSIVELY ON SULFATE… Organic carbon aerosol is the green part of the pie  globally more than sulfate [Zhang et al., in press] Sulfate Organics

4. MODELING FRAMEWORK Community Land Model (CLM3) Datasets: Lawrence and Chase [2007] Feddema et al. [2007] LAI (MODIS) Plant Functional Types Soil moisture Vegetation Temperature BVOC Algorithms [Guenther et al., 1995; 2006] Monterpenes: GEIA Isoprene: MEGAN Community Atmospheric Model (CAM3) Chemistry Transport Radiation BVOC Emissions Vegetation Meteorology Radiation Precipitation SOA production 2-product model from oxidation of: 1. Monoterpenes [Chung and Seinfeld, 2002] 2. Isoprene [Henze and Seinfeld, 2006] 3. Aromatics [Henze et al., 2007] Anthropogenic Emissions, GHG concentrations, SST

5. PRESENT-DAY (2000) SOA Isoprene is the largest SOA source in this simulation, and also the longest lived  dominates burden

6. PRESENT/PROJECTED BIOGENIC EMISSIONS 496 TgC/yr 2100: 607 TgC/yr 43 TgC/yr 2100: 51 TgC/yr 22% increase primarily driven by global temperature increases (1.8°C)

7. PRESENT/PROJECTED ANTHROPOGENIC EMISSIONS 45 TgC/yr 16 TgC/yr 2100: A1B: 20 TgC/yr A2: 35 TgC/yr 2100: A1B: 72 TgC/yr A2: 96 TgC/yr Large increases predicted, especially over Asia

8. CHANGES IN TOTAL SOA CONCENTRATIONS IN 2100 (A1B) FROM PRESENT-DAY Surface SOA Zonal SOA Δ Anthropogenic Emissions Δ Biogenic Emissions Δ Climate +7% Global Burden +26% +6%

9. CHANGES IN SOA CONCENTRATIONS IN 2100 FROM PRESENT-DAY DUE TO LAND-USE CHANGE (A2) SOA (TOTAL) BVOC emissions Feddema et al. [2007] Projections Expansion of croplands (low BVOC emitters) at the expense of broadleaf trees OVERALL SOA BURDEN: -14% Isoprene Monoterpenes

10. TOTAL EFFECT OF EMISSIONS & CLIMATE ON SOA Climate and Emission: +36% Anthropogenic Land-use: -14% Natural Vegetation: ?? TOTAL SOA

11. SOA SENSITIVITY SIMULATIONS: REGIONAL SOA SOURCES South America is the largest SOA source in present-day but significant growth expected for Asia by 2100 (and may overtake South America as the largest SOA source region under an A2 scenario).

12. CHANGES TO SOA PRODUCTION EFFICIENCY SOA production efficiency likely increase in EU and NA due to NOx ↓ but will decrease in urban regions of SH/tropics. 2000 2100-2000 SOA production is less efficient under high NOx conditions. Surface NO/HO 2

13. INCREASING SOA: CLIMATE IMPLICATIONS? Present-Day Burden: 0.5-0.7 TgS 1 Projection:↓ by > 50% by 2100? SULFATE SOA 1 [Koch et al., 1999; Barth et al., 2000; Takemura et al., 2000] Present-Day Burden: 0.59 TgC Projection: 36%↑ SOA Burden Andreae et al. [2005] suggest ↓ sulfate will accelerate greenhouse gas warming, but SOA may compensate