Mitigating BC Kristin Rypdal and Terje Berntsen Based on paper in prep. by Rypdal, Rive, Berntsen and Klimont All results preliminary

2 Current mitigation efforts Targeting PM 10, PM 2.5 or TSP with the objective of reducing health impacts –Will indirectly reduce emissions of BC Europe –LRTAP Convention –EU NEC Directive National policies and regional cooperation in most parts of the world

3 Questions Is mitigation of PM from the perspective of health concerns sufficient to also address the concerns we may have for RF caused by BC? What would be an efficient strategy to reduce radiative forcing caused by BC in terms of minimizing global costs?

4 Regional share of emissions (2030, CLE) Cofala et al. (2007)

5 CLE-MFR 2030 Cofala et al. (2007) CLE = Current Legislation; MFR = Maximum Feasible Reduction,

6 Share of sources (CLE 2030)

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8 Strategy Seek to maximize reductions in global RF from BC –1. Undertake reductions first in regions where the benefits per tonne BC reduced are the largest –2. As 1, but also minimizing global costs –3. As 2, but also considering regional ability to pay for abatement –4. Emphasize sources where PM exposure is large 5, 10 and 20 % in global RF by BC in 2030 MFR constitutes a ceiling to the amount abated

9 CLE MFR 10 % reduction in RF Increasing costsHigher RF reduction Regional costs Regional forcing

10 Open burning and OC When BC is abated OC is abated as well –Counterweight the benefit in terms of reduced RF Mitigating BC from biomass burning has no or little benefit in reducing net RF Open burning very important in Latin America and Africa (more important than contained) Cost estimates hard to define for open burning For simplicity we ignore biomass burning in the analysis shown here

11 Regional radiative properties Use GWP as an approximation –Arbitrary time-horizon Direct effect of BC in air Indirect effect of BC deposited on snow in the Arctic

12 Regional radiative forcing Regions GWP directGWP albedo Total GWP Europe Russia (RUS) North America (NAM) Latin America (LAM) Asia (China and India) South Asia (SAS) Africa (AFR) Source: Reddy and Boucher (2007)

13 Climate efficacies Temperature response of one unit RF of BC deposited on snow is larger than for the direct component Here we have multiplied the indirect GWP value by 3 (Flanner et al. JGR, 2007) Direct GWP; Total GWP; Efficacies

14 Abatement costs Consider cost of end-of pipe abatement Fuel switch is an important option for reducing BC emissions Marginal abatement costs for Europe available from the IIASA RAINS model –Per source, fuel and technology –Consistent with the emission scenarios used

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16 Abatement costs Lack comparable data for other world regions Use intervals of the Europe curve for other regions –Taking on board differences in source and fuel structure Technology assumptions –North-America as EU-17 –Other regions as Former Soviet Union

17 Costs (direct GWP only) GWP onlyMin costsAbility to payHealth focus

18 Regional abatement efforts

19 Sectoral abatement (S2)

20 Correction for income S2 = cost-effective; S3 = corrected for GDP

21 Health focus Ignoring biomass burning increases costs of reducing PM 10 emissions! Giving higher weight to sources and regions where exposure is high For fossil sources and processes emphasis on high-exposure sources does not substantially increase total abatement costs

22 Abating BC instead of CO 2 Complicated question! 100 years time horizon –5 % reduction in RF is inexpensive –10 % reduction in RF is Expensive considering the direct effect only Within the higher range of expected ETS prices considering the total GWP (30-40 Euro per tonnes) Efficacies: In the range of expected CO 2 (20-30 Euro per tonnes)

23 Conclusions Need better data on –regional abatement costs –Regional GWPs or other metric –OC metric? May want: –Higher regional resolution! Improved treatment of biomass burning (open and contained)

24 Conclusions Seeking global cost-effectiveness important to get political acceptance for additional mitigation efforts Primary focus on health concerns may not target sources where RF benefits are the largest Focus on abatement in Asia –Most cost-effective in terms of reducing global RF –Highest co-benefits in terms of reduced PM 10 emissions –Benefits for the Arctic?

25 Conclusions Poorer countries may not be able to pay for the globally most cost-effective reductions –Need a mechanism (“CDM”, fund)? Considering the indirect component of GWP from BC on snow and the climate efficacy should lead to higher abatement efforts in Europe –Does not increase overall cost as less tonnes BC need to be abated –Adds overall justification to abating BC rather than other forcing agents