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Historical Cropland Expansion Effects on the Short-Lived Climate Forcers

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Historical Cropland Expansion Effects on the Short-Lived Climate Forcers Historical cropland expansion effects on the short-lived climate forcers Nadine Unger Short-lived climate forcers (SLCFs) are important drivers of global climate change Radiative forcing of climate between 1750 and 2005 • Net effect of cooling SLCFs is masking the GHG warming by 50% (Ramanathan and Feng, PNAS, 2008) • Uncertainty in SLCFs compromises understanding of climate sensitivity • Interactions between SLCFs and land-use change poorly understood, not represented here (Forster et al., IPCC AR4, 2007) The real climatic impacts of the economic sectors Sector profiles differ greatly 20-30 year time horizon SLCF effects important relative to CO2 in the near term 500 SLCF effects 400 enhance GHG warming 300 ) -2 Carbon Dioxide 200 Nitrous Oxide warming 100 Methane AIE 0 Organic carbon Black carbon -100 Nitrate -200 Sulfate Ozone Radiative forcing (mWm -300 -400 cooling SLCF effects offset GHG warming -500 Power Industry Shipping Aviation On-road Agriculture Off-road land Waste/landfill Biomass burning Household biofuel Agr. waste burning Animal Husbandry Household fossil fuel increasing net warming (Unger et al., PNAS, 2010) Global public health impacts by economic sector !"#$%%&'()*+,-(%#./()&0,)1(/+2$%&34)+5.1(5/$&1,&60789&&& :;$2%)L) I;1(M'') N/) O&+PP+18) 7Q+;R"1) 783+K#'2#3%) 5/) 5/) ?G@A";()HI;1(J) -/) -/) 71+=;')!#$F;1(34) ./) D"E%3) ./) !"#$%&"'()*+",#%') -./) !"#$%&"'()B"$$+')B#%') C/) ?1@A";() >/) *+"=;$$)*#31) >/) 01(#$234) 7839):;$2%)*#31) 56/) </) (Sarma, Unger, Jack, Kinney, submitted, ERL, 2012) Global health impacts from mobile sources of fine particulate matter emissions in 2000 µgm-3 circle size proportional to mortality rates (per 100,000) attributable to mobile source emissions • 18 percent of early deaths from total outdoor air pollution was associated with mobile emission sources in 2000 • 13 deaths per 100,000 people per year were attributable to mobile emission sources (an estimated 19 deaths per 100,000 people per year are due to road traffic collisions) (Chambliss, Zeinali, Unger, Minjares, EHP, submitted, 2012) Clean the Air, Heat the Planet? Data from (Kloster et al., J. Clim., 2009) (Levy et al., U.S. CCSP, 2008) T(GHGs) T(GHGs) ! full implementation of aerosol control technology (best case for air quality) 100% 20-40% T(Air Pollutants)/ ! • Modeling estimates of climate impact from future air pollution abatement • Large potential impact of future air pollution control strategies on climate • Is accelerated warming due to future air pollution abatement inevitable? • Climate change policies may have to include a pollution safety margin in GHG reduction targets (Arneth, Unger, Kulmala, Andreae, Science, 2009) CO2 emission reduction measures alone are not sufficient to keep global warming below 2°C UNEP/WMO, 2011 Overview of interactions between land ecosystems and SLCFs Photo-oxidation O ! isoprene 2 h ! ! O3! Atmospheric chemistry BVOC emission STRATOSPHERE! 8-18 km! f(plant type, T,PAR,LAI, TROPOSPHERE! h!! NO ! leaf age, soil wetness) 2 NO! O ! h , H O! monoterpenes 3 ! 2 OH! HO2! H2O2! Deposition! CO, VOC! SLCFs O3 deposition O3 ↓ OH = ↑ CH4 lifetime Low NOx↓ Aerosol effects High NOx↑ on radiation, SOA precipitation CH4 NOx AVOCs CO SO2 RF NH3 soot POM Δ Land cover Δ Δ Anthropogenic influence + FEEDBACKS FROM CLIMATE CHANGE (ΔCO2, T, precipitation, hv) Effects of global change drivers on BVOC emissions CO2-inhibition off CO2-inhibition on 2100-PD 2100-PD LGM-PD (Arneth et al., GRL, 2007) Coupling atmospheric chemistry to global carbon cycle in NASA ModelE • Implemented new leaf biophysics model into vegetation canopy scheme • 2 land cover sets available • Standard GISS 8 biome • MODIS 6 PFTs • ModelE GPP = 110PgC/yr (GISS COVER) • FLUXNET GPP = 120PgC/yr (FLUXNET data from M. Jung et al., 2011) (Unger et al., in submission, 2012) Global isoprene emission and the land carbon sink in NASA ModelE • Implemented photosynthesis-dependent isoprene emission following Niinemets et al., 1999 • Accounts for CO2 inhibition • Monoterpene emission 2 options • Temperature-dependent only • Process-based (includes photosynthetic production rate and leaf storage/release) • Global isoprene emission = 400 TgC/yr • Extensive evaluation • Database of 25+ campaign average fluxes • Test seasonal integrity of model from limited # of campaigns [Harvard Forest (1995, 2007; Tapajos (2000, 2001, 2003); Costa Rica (2003); Manaus (2004); Montmeyan (2001); La Verdiere (2000); UMBS (1999-2003, 2005); OP3 Borneo (2008)] (Unger et al., in submission, 2012) Future anthropogenic land cover change impacts on BVOC emissions Δ 2100-2000 RCP2.6 RCP4.5 Afforestation climate policy RCP6.0 RCP8.5 Cropland area expands increasing food demand population = 12 billion (10-12kg/m2/s) Global isoprene source strength sensitivity ±15 % Acknowledgements Thank you for listening Kandice Harper (Yale FES) Xuhui Lee (Yale FES) Almut Arneth (Lund University, Sweden) Guy Schurgers (Lund University, Sweden) Igor Aleinov (NASA GISS) Nancy Kiang (NASA GISS) .
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