uncertainty in aerosol emissions
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Uncertainty in aerosol emissions. Joyce E. Penner University of Michigan Presented to UNFCC Expert meeting London September 24-26, 2002. Validation of climate attribution models. - PowerPoint PPT PresentationTRANSCRIPT
Uncertainty in aerosol emissions
Joyce E. Penner
University of Michigan
Presented to UNFCC
Expert meeting
London
September 24-26, 2002
Validation of climate attribution models
• Use IPCC recommended methods for deriving direct and indirect forcing from fossil fuel emissions (These have been tested by comparison with present day surface measurements and total optical depth):– SO4
2-
– BC– OC
• Reconstruct historical emissions• Test with change in global or hemispheric surface
temperature
Sources of uncertainty in past aerosol emissions
• Reconstructed historical fuel use by sector
• Assumed historical emission factors by technology development
Example: Coal use by sector for OECD (breakdown not available for non-OECD)
• Hard coal– Energy sector– Transformation– Industry sector– Transport sector
– Other sectors (residential)
• Lignite• Brown coal coke• Coke-oven coke• Gas coke• Hard coal briquettes• Lignite briquettes• Charcoal
Total coal use reconstructed from:
0
500
1000
1500
2000
2500
3000
3500
4000
4500
1950 1960 1970 1980 1990
Year
To
tal c
oal
(10
00 k
g/y
r)
AfricaAsiaLatinEuropeN. AmericaOceaniaTotal
0
500
1000
1500
2000
2500
3000
3500
4000
4500
1950 1960 1970 1980 1990
Year
To
tal c
oal
(10
00 k
g/y
r)
AfricaAsiaLatinEuropeN. AmericaOceaniaTotal
ES, ESAB, ESY, WES (consumption data)
UN Data tapes andFormula based on production, etc.
Total lignite use reconstructed from:
0
200
400
600
800
1000
1200
1400
1950 1960 1970 1980 1990
Year
To
tal l
ign
ite
(100
0 kg
/yr)
AfricaAsiaLatinEuropeN. AmericaOceaniaTotal
0
200
400
600
800
1000
1200
1400
1950 1960 1970 1980 1990
Year
To
tal l
ign
ite
(100
0 kg
/yr)
AfricaAsiaLatinEuropeN. AmericaOceaniaTotal
ES, ESAB, ESY, WES UN Data tapes
Reconstructed sulfur emissions
0
10
20
30
40
50
60
70
80
90
1850 1900 1950 2000
year
sulf
ur
emis
sio
ns
(Mto
n/y
r) LeFohn
Rodhe
Dignon*1.15
Example: Range of estimated emission factors for BC for developing world (g/kg):
• Coal residential
• Lignite residential
• 7 - 12
• 16 - 4.6
Cooke - Bond(quote in Bond)
Estimated emissions of BC (Tg/yr):
• Power generation• Industry• Res. Coal• Residential other• Transport diesel• Transport other
• Total
• 0.12 - 1.54• 0.29 - 1.19• 0.9 - 0.64• 0.18 - 0.50• 0.51 - 2.83• 0.19 - 0.11
• 2.19 - 6.81
Bond Cooke
These new emissions underestimate BC when used in models
BC emissions from fossil fuels (using Cooke emissions factors)
0
1
2
3
4
5
6
7
8
9
1950 1960 1970 1980 1990Year
BC
em
iss
ion
s (
Tg
/yr)
Africa Asia Latin Europe
N. America Oceania Total
Recommend that IPCC should conduct:
• Comparison of fuel reconstruction by:– Ardenne, Liousse, Bond, Penner, LeFohn, Marland,
Smith, Novakov - include regional emissions estimates (Reddy for India)
• Comparison of emission factors• Derivation of recommended historical emissions
and uncertainty range• Continued evaluation of aerosol forcing using
models compared to observations• Open question: Evaluation of forcing by
comparison with hemispheric temperature trends?
Open questions
• Can we use comparison with hemispheric temperature trends to evaluate historical aerosol forcing?
• How well do we need to know the aerosol forcing and ozone forcing to derive the climate sensitivity?
• How do we treat historical biomass burning emissions?