Treatment of Uncertainties for National Estimates of Greenhouse Gas Emissions



Table 1. Estimated Uncertainties in the Carbon Dioxide Inventory in 1990 and 2010



Source Activity Uncertainty % Emission Factor Uncertainty % Uncertainty in Emission %
Coal 1.2 6 ‡
Coke 6 3 ‡
Petroleum Coke 5 3 ‡
SSF 3 3 ‡
Burning Oil 6 2 ‡
Fuel Oil 4 2 ‡
Gas Oil/Diesel Oil 1.4 2 ‡
Motor Spirit 0.8 2 ‡
Orimulsion 1 2 ‡
Aviation Fuel (Domestic) 50 2 ‡
Natural Gas 2 1 ‡
Colliery Methane 5 5 ‡
LPG 24 3 ‡
OPG 1 3 ‡
Ammonia Production - - 5
Cement 1 2 ‡
Lime 1 5 ‡
Flaring - - 14
Waste Incineration 7 20 ‡
5A Forest biomass change - - 30
5A Timber products change - - 50
5B Forest & Grassland Conversion - - 50
5B Forest & Grassland Conversion - - 60
5C Abandonment - - 50
5D Peat Extraction - - 10
5D Peat Drainage - - 50

Table 2. Carbon Dioxide Emissions/Sinks Due to Land Use Change


IPCC Table Title Process 1990 Uncertainty 2010 Uncertainty2 Comment
5A Sheet 1 Forestry Forest biomass change 30 40 Variation in model parameters
5A Sheet 2 Forestry Timber products change 50 50 Variation in model parameters
5B Sheet 3 Forest/grassland conversion Above ground biomass decay (grassland) 50 50 Expert judgement
5B Sheet 4 Forest/grassland conversion Soil carbon release (grassland) 60 90 Variation in model parameters
5C Sheet 1 Abandonment Set aside 50 50 Variation in model parameters
5D Other Upland peat drainage 50 50 Expert judgement
5D Other Lowland wetland drainage 50 50 Expert judgement
5D Other Peat extraction 10 10 Expert judgement


Table 3. Estimated Uncertainties in the Methane Inventory
Source Source Uncertainty % Reference Density Function Format
Fuel Combustion 50 ‡ truncated normal
Landfill ~39 [15] empirical distribution
Livestock: enteric 20 [16] normal
Livestock: wastes 30 [16] normal
Coal Mining 13 [17] normal
Gas Leakage 17-75 [16] normal or truncated normal depending on category
Offshore 28 ‡23 normal
Sewage Sludge 50 [18] truncated normal

Table 4. Key Parameters Used in Estimation of Uncertainties in Emissions of Nitrous Oxide
  Emission Factor Uncertainty % Activity Rate Uncertainty %
Agricultural Soils log-normal 0
Adipic Acid 15 0.5
Nitric Acid 230 10-20
Power Generation Coal Oil Orimulsion Natural Gas 195 140 140 110 1.2 4 1 2.4
Road Traffic 170 10
Table 5. Key Parameters Used in Estimation of Uncertainties in Emissions of
Halocarbons and Sulphur Hexafluoride

Probabilistic Model Parameters Domestic Fridge Mass Produced Hermetic Refrigeration Supermarket Distributed Systems Small Commercial Distributed Systems Air Conditioning Distributed Systems Industrial Distributed Systems Central Chillers Refrigerated Transport Mobile Air Conditioning Systems Polystyrene Foam Polyurethane Foam PFC Foam
PM factor                        
Mean 0.01 0.01 0.03 0.03 0.03 0.03 0.01 0.01 0.01 0.6 0.1 0.1
Uncertainty 0.5 0.5 0.33 0.33 0.33 0.33 0.5 0.5 0.5 0.33 0.5 0.5
PL factor                        
Mean 0.01 0.01 0.3 0.3 0.3 0.2 0.03 0.15 0.15 0.2 0.01 0.01
Uncertainty 0.5 0.5 0.2 0.2 0.2 0.2 0.33 0.2 0.2 0.2 0.5 0.5
D factor                        
Mean 0.5 0.5 0.1 0.1 0.1 0.1 0.05 0.15 0.25 1 1 1
Uncertainty 0.2 0.2 0.2 0.2 0.2   0.4 0.2 0.2      

Probabilistic Model Parameters Aerosols Fire fighting Electronics 1 (PFC uses) Electronics 2 (SF6 use) Electronics 3 NF3 not included Electronics 4 (HFC uses) Electrical (SF6 use) HCFC22 Manufacture HFC134a Manufacture HFC32 Manufacture PFC Manufacture
PM factor                      
Mean 0.02 0.01 0 0 0 0 0.01 0.04 0.005 0.005 0.005
Uncertainty 0.25 0.5         0.5 0.25 0.4 0.4 0.4
PL factor                      
Mean 1 0.03 0.2 0.2 0.2 0.2 0.005        
Uncertainty   0.33 0.2 0.2 0.2 0.2 0.4        
D factor                      
Mean 0 0.05 0.05 0.05 0.05 0.05 0.02        
Uncertainty     0.4 0.4 0.4 0.4 0.5        
Table 6. Global Warming Potentials (GWP100) Used in Analysis


Species Global warming potential (GWP100) Species Global warming potential (GWP100)1
CO2 1 HFC23 11700
CH4 21 HFC32 650
N2O 310 HFC125 2800
CFC11 3800 HFC134a 1300
CFC12 8100 HFC143a 3800
CFC13 13000 HFC152a 140
CFC113 4800 HFC227ea 2900
CFC114 9300 PFC14 6500
CFC115 6900 PFC116 9200
HCFC22 1500 PFC218 7000
HCFC123 90 PFC318 7000
HCFC124 470 PFC410 7000
HCFC141b 600 SF6 239000
HCFC142b 1800    



Table 7. Significant Rank Order Correlation Coefficients in the Estimates of Greenhouse Gas Inventory

Pollutant Source 1990 2010 % change between 1990 and 2010
HFC HCFC 22 Manufacture 0.99   -0.94
  Supermarket Refrigerators   0.58  
  Polyurethane Foam Manufacture   0.38  
  Air Conditioning Leaks   0.34  
  Polyurethane Foam Leaks during use   0.30  
PFC Manufacture of Aluminium 0.99 0.42 -0.83
  Firefighting   0.78 0.44
SF6 Magnesium Manufacture (cover gas) 0.93 0.91 -0.68
  Electrical Switch Gear (leakage)   0.30