Uncertainty Analysis

Quantification of uncertainty in GHG emission estimates following IPCC guidelines at the 95% confidence interval

FY 2022 Inventory

Overall Inventory Uncertainty (Level)

+/- 8.4%

95% confidence interval

Trend Uncertainty

+/- 4.8%

Year-on-year change

Method

IPCC Approach 1

Propagation of errors

SectorCategoryEmissions (Gg CO2eq)AD Uncertainty (%)EF Uncertainty (%)Combined (%)SensitivityKey?
Energy

Energy Industries - Fuel Combustion

1.A.1

39,180+/- 5+/- 7+/- 8.6
35.2%
Key
Energy

Transport - Road

1.A.3

14,050+/- 8+/- 5+/- 9.4
13.8%
Key
Agriculture

Enteric Fermentation

3.A

11,190+/- 10+/- 30+/- 31.6
18.4%
Key
IPPU

Cement Production

2.A.1

7,770+/- 5+/- 10+/- 11.2
8.5%
Key
LULUCF

Forest Land

4.A

6,660+/- 30+/- 50+/- 58.3
10.1%
Key
Energy

Manufacturing Industries

1.A.2

4,710+/- 5+/- 7+/- 8.6
4.2%
Key
Agriculture

Agricultural Soils (N2O)

3.D

3,510+/- 50+/- 100+/- 111.8
9.2%
Key
Waste

Solid Waste Disposal

5.A

2,220+/- 30+/- 40+/- 50.0
6.5%
-
Energy

Oil & Natural Gas Fugitive

1.B.2

1,660+/- 20+/- 50+/- 53.9
4.7%
-
Agriculture

Rice Cultivation (CH4)

3.C

1,110+/- 20+/- 40+/- 44.7
2.6%
-

Overall Inventory Uncertainty Result

Calculated as: U_total = sqrt( sum( (U_i x E_i / E_total)^2 ) ) for all categories

+/- 8.4%

at 95% confidence

Methodology: IPCC Approach 1 - Propagation of Errors

Uncertainty is estimated using IPCC Approach 1 (error propagation), combining activity data (AD) and emission factor (EF) uncertainties at the 95% confidence interval. The combined uncertainty for each category is calculated using the equation: U_combined = sqrt(U_AD^2 + U_EF^2). The overall inventory uncertainty is then derived by weighting each category's combined uncertainty by its share of total emissions. Sensitivity analysis identifies which categories contribute most to overall uncertainty, guiding improvement priorities. Reference: 2006 IPCC Guidelines, Volume 1, Chapter 3.