Black carbon: Emission sources & prioritization

Transcription

1 Black carbon: Emission sources & prioritization Tami C. Bond University of Illinois at Urbana-Champaign 5 January 29 ICCT Black Carbon Workshop, London, UK This trip by Carbonfund.org

2 Outline 1. Present-day emission sources 2. (Aside: Timing) 3. Future emission sources 4. (Aside: Forcing values) STATE OF KNOWLEDGE Ready for action? What do and don t we know? Does the magnitude of this uncertainty prevent decision?

3 Present-day Major emission sources (2) Power % Industry 11% Open burning 41% Residential: Biofuel 18% Transport: Road 16% Transport: Non-road 9% Residential: Other Residential: 1% Coal 4% 2 energy data; Includes updates in: residential coal (Chen, Zhi meas); residential biofuel (Venkataraman, Roden meas); industrial coal (Zhang meas; Streets technology divs); coal for power generation (new DRI meas posted & discussion with Liousse group); twostroke engines (Volckens meas); shipping (Lack meas); diesel vehicles in developing countries (World Bank DIESEL project)

4 Present-day Inventory uncertainties? Emission estimates ARE quite uncertain Factor 2-1, depending on sector BUT, models are semi-constrained Remote measurements within ~x2 Urban measurements within ~x1 (spatial mismatch problem could be only ~3) D. Koch et al. J. Geophys. Res., 112, doi:1.129/25jd724, 27.

5 Quick assessment of potential reduction Significant emission plus low OC/BC ratio Present-day Industry: Possible Transport: Definite Residential: Maybe Large OC/BC variability Open burning: Doubtful Near-Arctic sources may be exception Open burning Power Res: Biofuel OC/BC ratio Industry Res: Coal * * * * Transport: Road Transport: Non-road Res: Other Power Industry Transp: Road Transport: Non-road Res: Other Res: Coal Res: Biofuel Open burning * Significant sulfate, too

6 e d u t i t a L Near Arctic: Transport, industry, some residential Power Industry Res fossil fuel Res biofuel Transportation Crop waste Open burning BC emissions (Gg/year) N of 4: ~15 Gg Affects warming & snow albedo S of 4: ~65 Gg Affects atmospheric warming May affect Arctic albedo after transport Warms atmosphere? YES MAYBE

7 Present-day Major emission sources Change in major categories highly unlikely Sectoral contribution percentages uncertain by ~5% STATE OF KNOWLEDGE i.e. 2% could be 3% Atmospheric concentrations Do we know enough to work on transportation sources? YES. Significant contribution of BC Inventories, if biased, are probably low OC/BC ratio is variable, but will not produce cooling UNLESS we discover something weird & wild about the indirect effect

8 Present-day Importance of sub-sector contributions E d / f d (.6.5 Large emission from small fraction means: Difficult to quantify an major but elusive element Targeted action can produce significant reductions y c n e u q e r F Emission rate 35% of emissions 7% of emissions 5% of emissions

9 Present-day STATE OF KNOWLEDGE Sub-sector contributions/transport On-road Normal vehicles well known on average Some uncertainty caused by in-use versus laboratory Contribution of superemitters uncertain Both emission rates & quantities unknown Off-road, construction/industry Average is NOT well known Especially in Asia/Africa! All questions above apply Off-road, shipping Normal operators well known on average Corbett s s guesses trump Bond s s (including rail?) BC fraction IS NOT the major uncertainty now Ready to act? Just a minute

10 Priorities beyond standard on-road work Better assessment of emission distribution Can we easily target a sub-set? Collect off-road activity data Initial assessment of off-road emission rates Places to start: U.S. EPA Encourage countries to estimate non-road in addition to on-road

11 Timing Four key time questions (1) Long-lived Short-lived e Action t c Emission atmospheric Concentration i made up don t cite! dt t t direct impact Forcing climate Response t Impact (good or bad)

12 Timing Four key time questions (2) Long-lived Short-lived 4 Horizon/discounting i t THE DISTANT FUTURE NOW Action Emission atmospheric Concentration direct impact Forcing climate Response Impact (good or bad)

13 Timing The problem of timing IF metric is based on convolution of responses (and maybe it should be) THEN timing of emission decrement matters Imposes (messy) requirement: Determine BASELINE not just HOW MUCH, but WHEN.

14 Future emissions Basic rules for projecting future emissions 1. There are two opposing mechanisms 1. DECREASE in emission intensity [pollutant per fuel] 2. INCREASE in fuel consumption Who wins? Matter of faith (and assumptions) 2. Everything that is uncertain today is uncertain in the future Unless it vanishes. In that case, the rate of vanishing causes the uncertainty.

15 Future emissions Normal cars LD diesel only WEur SAsia World Fuel (Mtonne) BC (Gg) SUPER 12EUROVI EUROV 1 EUROIV 8EUROIII EUROII 6EUROI OPAC 4 NONE SUPER 7 EUROVI 6EUROV 5 EUROIV EUROIII 4EUROII 3 EUROI OPAC 2NONE SUPER EUROVI EUROV EUROIV EUROIII EUROII EUROI OPAC NONE SUPER EUROVI EUROV EUROIV EUROIII EUROII EUROI OPAC NONE Japan Oceania South East Asia East Asia South Asia Middle East Former USSR Eastern Europe OECD Europe Southern Aftrica Eastern Africa Western Africa Northern Africa South America Central America USA Canada Japan Oceania South East Asia East Asia South Asia Middle East Former USSR Eastern Europe OECD Europe Southern Aftrica Eastern Africa Western Africa Northern Africa South America Central America USA Canada

16 Future emissions LD Diesel with superemitters WEur SAsia World Fuel (Mtonne) BC (Gg) SUPER SUPER 12 EUROVI EUROVI 14 EUROV EUROV 1 12 EUROIV EUROIV 1 EUROIII 8 EUROIII EUROII EUROII 8 EUROI 6 EUROI 6 OPAC OPAC 4 4 NONE NONE SUPER SUPER EUROVI EUROVI 2 EUROV EUROV 15EUROIV EUROIV 15 EUROIII EUROIII EUROII EUROII 1EUROI 1 EUROI OPAC OPAC NONE 5 5 NONE Japan Oceania South East Asia East Asia South Asia Middle East Former USSR Eastern Europe OECD Europe Southern Aftrica Eastern Africa Western Africa Northern Africa South America Central America USA Canada Japan Oceania South East Asia East Asia South Asia Middle East Former USSR Eastern Europe OECD Europe Southern Aftrica Eastern Africa Western Africa Northern Africa South America Central America USA Canada

17 Future emissions It s the economy, stupid World b1 (previous slides) World a1b Fuel (Mtonne) BC (Gg) Japan Oceania South East Asia East Asia South Asia Middle East Former USSR Eastern Europe OECD Europe Southern Aftrica Eastern Africa Western Africa Northern Africa South America Central America USA Canada Japan Oceania South East Asia East Asia South Asia Middle East Former USSR Eastern Europe OECD Europe Southern Aftrica Eastern Africa Western Africa Northern Africa South America Central America USA Canada % higher % higher Japan Oceania South East Asia East Asia South Asia Middle East Former USSR Eastern Europe OECD Europe Southern Aftrica Eastern Africa Western Africa Northern Africa South America Central America USA Canada Japan Oceania South East Asia East Asia South Asia Middle East Former USSR Eastern Europe OECD Europe Southern Aftrica Eastern Africa Western Africa Northern Africa South America Central America USA Canada

18 Future emissions STATE OF KNOWLEDGE Future transport emissions (I) On-road relatively well constrained (compared to everything else) We understand how normal vehicles could change Many regulations already underway Sticky baseline question What would have happened anyway? Economics is one of the biggest uncertainties Somewhere between current legislation and max feasible

19 Future emissions STATE OF KNOWLEDGE Future transport emissions (II) Off-road NOT well constrained Average emission rate not well known Affects MAGNITUDE, not total reduction Rebuild frequency & quality To original regs?? to current regs? Regulation drivers no history, how to predict? Action OK, or uncertainty too high? Large potential; low OC/BC ratio On-road: Prove that more than incremental difference is possible Off-road: Almost any action will reduce emissions

20 Future emissions Conundrum for all sectors Regulatory interest Measurement & quantification Reductions are already planned for measured, quantified sources To take advantage of missed opportunities,, need: - a metric that is flexible but unbiased - treatment of uncertainty that is rigorous but not repressive

21 Final note Modeled forcing values used in metrics One model is not enough Even if it is best Everyone should learn from the best models Multiple models are not enough Highlight diversity/uncertainty, BUT agreement can indicate similar assumptions (mistaken or otherwise) Intercomparisons typically done with simple models Observations are not enough Divergence from models must be explained, not adjusted

22 Final note A simple model test Three processes that increase positive forcing: 1. BC mixing with other aerosol 2. Deposition on snow and ice 3. Lofting above clouds Many models do not include these (1 & 2) or corroborate them (2 & 3)

23 Supplemental slides

24 General rule about BC emitters (for energy-related sources) Emitter size More information Reporting requirements more stringent High emissions from small sources with little information Greater efficiency For large actors, poor efficiency = greater financial losses improved technology or controls are relatively more affordable More fuel consumed More emissions per fuel

25 Diesel results - global average l u m i s f o n o i t c a r F Forcing positive: 93% probability >2% of 2-year CO 2 : 7% prob >2% of 1-yr CO 2 forcing: 21% prob Emission rates & composition from DIESEL project Total energy added during lifetime (GJ)

26 Region-specific diesel impacts Same emission rates, same properties Warning: Preliminary! East Asia Global avg South Asia f o n o i t c a r F Total energy added during lifetime (GJ) Fraction in Arctic Fraction in Arctic

27 OC/EC ratio from diesel engines 8% 6% 9 pre-reg LDDV 6 early reg LDDV 3 EURO-I LDDV 13 EURO-II LDDV 33 LDDV Light duty 4% 2% % OC/PM EC/PM Other/PM 8% 6% 1 pre-reg buses 4 early reg buses 12 EURO-I buses 17 EURO-II buses 2 pre-reg trucks 7 early reg trucks 1 EURO-II trucks 7 trucks and buses Heavy duty 4% 2% % OC/PM EC/PM Other/PM