Black Carbon and Agriculture - Source and Impacts

Transcription

1 Black Carbon and Agriculture - Source and Impacts M. Maione 1,2 F. Graziosi 1, J. Arduini 1, F. Furlani 1, U. Giostra 1, A. Marinoni 2, R. Duchi 2 1 University of Urbino, Italy 2 ISAC-CNR Italy michela.maione@uniurb.it WMO-IMD International Conference Atmospheric Chemistry and Agricultural Meteorology 2-4 November 2015 Pune

2 Outline Agricultural related BC emissions Impacts of BC on agriculture Use of observation data The policy framework

3 What is black carbon (BC)? BC aerosol particles result from the incomplete combustion of fossil fuels, wood and other biomass; BC is emitted directly into the atmosphere in form of fine particles (primary PM 2.5 ); BC can be defined as the carbonaceous component of PM that strongly absorb light at all visible wavelengths; Per unit of mass in the atmosphere, BC can absorb a million times more energy than CO 2.

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5 Global bottom-up emission (in 2000) 7500 Gg BC yr- 1 (2000 to 29,000 Gg yr -1 ) About 4800 Gg are from energy-related burning, about 2800 Gg are from open biomass burning Asian and African main sources are residential coal and biomass burning In EU and America are on-road and non-road diesel engines

6 Emission sources rapidly changing: bottom-up inventories indicate that Asian emissions may have increased by 30% between 2000 and 2005 India contribution is estimated between 7 to 14% of global emissions. BC emission inventories for India. a) ECLIPSE v5 + GFED v3; b) ECLIPSE-RETRO; c) ECLIPSE-SAFAR India

7 Emission from the agricultural sector Difficult to estimate, poorly quantified; Only large agricultural fires can be detected with remote sensing; The practice of agricultural waste burning has strong regional and crop-specific differences and large seasonal variations.

8 Emission rates of BC in 2000 by source categories Bond at al, JGR, 2012

9 Direct effects of BC on vegetation Changes in surface air temperature; BC absorbs light decrease solar radiation reaching the surface and changes in the direct-to-diffuse radiation ratio; Increasing amounts of scattering aerosols enhance the diffuse component: plants are overall more efficient under diffuse radiation conditions; increasing concentrations of absorbing aerosols have the opposite effect.

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11 BC is a SLCP radiative forcing is regional Annual mean direct radiative forcing by BC from1850 to present day

12 BC induced climate effects on agriculture Impacts through the effect on temperatures, cloudiness, rainfall and river flow (via glacier melting); In regions affected by the ABCs 1, surface warming due to GHGs and BC would decrease rice productivity, amplified by a decrease in monsoon rainfall; of the total effect on agriculture of ABCs, 70% could be due to BC and OC Estimated losses of ABCs on rice harvest: 4 % (1966 to 1984) and 11 % (1985 to 1998) (Auffhammer et al., 2006) CLOUDS 1 ATMOSPHERIC BROWN

13 Increased vulnerability of agriculture to BC Agricultural production will be affected by changes in regional climate especially through alterations in precipitation reliability and timing increased frequency and severity of flooding or droughts warmer temperatures increase demand for irrigation and yields reduction.

14 USE OF OBSERVATION DATA

15 Observations: Mt Cimone (Italy) 2160 asl Trend: ± 0.8 % year -1 Station Climatology DTEs Conclusions Perspectives Equivalent BC

16 Constraining emissions from observations Understanding the sources of BC and their geographical distribution is important to improve climate modelling and support the developing of policies exploring climate cobenefits of BC controlling sources. Bottom-up emissions estimates: multiplying emission factors by activity data Top-down emission estimates: combining models with observations

17 Emission of BC though a Bayesian Inversion 1 x1 wind fields (ECMWF data); backward particle release, every 3 h to derive the source-receptor relationship (SRR); Wet and dry deposition have been taken into account; The FLEXPART model does not simulate chemical reactions nor microphysics, so BC is treated in a simplified way; The SRR is multiplied by an a priori emission field (ECLIPSE data base v4, 2010 scenario); Compared with observations from 11 stations in Europe.

18 European a posteriori emissions (2011) BC European emissions apriori posteriori

19 Tibet Nepal India N 27 57' E 86 48' 5079 m asl NEPAL CLIMATE OBSERVATORY N-COP Indian Ocean

20 The Nepal Climate Observatory-Pyramid N, E, 5079 m a.s.l ng m PRE-MONSOON MONSOON POST-MONSOON DRY 0 0:00 2:00 4:00 6:00 8:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 0:00 UTC + 4:45

21 Time series (daily averages) of BC (black) relative humidity (green) and acute pollution events (red dots) at NCO-P from March 2006 to December Based on BC measurements at NCO-P, Yasunari et al. (2010) estimated that the dry deposition of BC in snow could result in a 2.0% to 5.2%, albedo reduction. Great importance in a region where future evolution of glacier and water resources is key to food security and hence political stability.

22 NCO-P source-receptor relationship

23 POLICY RECOMMENDATIONS

24 BC mitigation: a win-win policy option 2011 UNEP-WMO Assessment on O 3 and BC was aimed at understanding the extent to which addressing emissions could contribute to reducing the rate of warming and what health and ecosystem (including crop yields) benefits would be delivered

25 Assessment Objectives To assess the extent by which carefully identified measures using existing technology to address BC and ozone can help protect near-term global and regional climate change Determine the co-benefits of the selected measures on health and crops Identify how the selected measures can be widely implemented with reference to case studies

26 BC Measures that reduce emissions of black carbon and coemissions (e.g. OC, CO) Diesel vehicles (particle filters+) Coal briquettes replacing coal in residential stoves Pellet stoves & boilers replacing residential wood burning in industrialized countries Clean-burning cookstoves in developing countries Modern brick kilns Modern coke ovens Ban of open burning of agricultural waste

27 O 3 -BC and CO 2 measures are complementary not mutually exclusive

28 As well as climate benefits there are also major benefits for health and food security

29 BC in the EU legislation The new EU AQ package includes a revised National Emission Ceiling Directives (NECD); The NECD adopts the revised Gothenburg Protocol agreed in May 2012 in the CLRTAP within the UNECE; The revised Protocol includes an emission ceiling for primary PM2.5 and requires reducing source with high proportions of BC in achieving the PM2.5 ceilings; The revised NECD also includes emission reduction obligations for CH 4 (O 3 precursor); The inclusion of climate forcers such as BC, CH 4 and O 3 establishes the first legislative link between air quality issues and global warming.

30 Final remarks Agriculture is an important source of BC BC can affect crop yields through its effects on radiation and regional climate The effect of BC deposition on glaciers is a relevant issue in South and East Asia Policies addressing BC will produce beneficial effects on climate and crop yields (as well as human health)