Mitigating BC

Kristin Rypdal and Terje Berntsen

Based on paper in prep. by Rypdal, Rive, Berntsen and KlimontAll results preliminary

2

Current mitigation efforts

• Targeting PM10, PM2.5 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)

Europe, Russia and N-America

13 %

Africa and L America

22 %

CPA (China)33 %

South Asia19 %

East Asia & Pacific13 %

Cofala et al. (2007)

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CLE-MFR 2030

0

100

200

300

400

500

600

Europ

e

Russia

N Am

erica

L Am

erica

Africa

CPA

East A

sia

South

Asia

Gg

Cofala et al. (2007)

CLE = Current Legislation; MFR = Maximum Feasible Reduction,

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Share of sources (CLE 2030)

EU-17

Industrial Processes

2 %

Transport35 %

Domestic33 %

Residential and Agri Waste

7 %

Open Burning22 %

7

Share of sources (CLE 2030)

CPA (China)

Industrial Processes

11 %

Domestic66 %

Residential and Agri Waste

10 %

Open Burning3 %

Transport8 %

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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

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CLE

MFR

10 % reduction in RF

Incre

asin

g co

sts

Hig

her R

F red

uctio

nRegional costs

Regional forcing

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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

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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

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Regional radiative forcing

Regions GWP direct GWP albedo Total GWP

Europe 384 1210 1594

Russia (RUS) 430 96 526

North America (NAM) 413 244 656

Latin America (LAM) 666 64 730

Asia (China and India) 430 96 526

South Asia (SAS) 612 64 676

Africa (AFR) 691 64 755

Source: Reddy and Boucher (2007)

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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

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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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Black Carbon MAC, EU17 in 2030

0

100000

200000

300000

400000

500000

600000

700000

800000

900000

1000000

0 10000 20000 30000 40000 50000

tBC reduced from CLE

Eur

os p

er tB

C

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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

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Costs (direct GWP only)

0

20

40

60

80

100

120

S1 S2 S3 S4

Bill

ion

Eur

o

10 % RF

5 % RF

GWP only Min costs Ability to pay Health focus

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Regional abatement efforts

050

100150200250300350

CPA(China)

SouthAsia

Europe NorthAmerica

Other

Mg

5 % Direct

5 % Total

5 % Efficacy

10 % Direct

10 % Total

10 % Efficacy

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Sectoral abatement (S2)

0

100

200

300

400

500

600

700

800

Domestic Road/off-road

Industry Industrialprocesses

Othertransport

Mg

5 %

10 %

MFR

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Correction for income

S2 = cost-effective; S3 = corrected for GDP

050

100150200250300350

CPA(China)

SouthAsia

Europe NorthAmerica

Other

Tg

5 % S2

5 % S3

10 % S2

10 % S3

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Health focus

• Ignoring biomass burning increases costs of reducing PM10 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

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Abating BC instead of CO2

• 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 CO2 (20-30 Euro per tonnes)

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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)

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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 PM10 emissions

– Benefits for the Arctic?

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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