The Climate Action Monitor 2026

Annex A. Chapter 1

Country GHG emissions estimates

Country-level data are based on emissions inventories reported to the United Nations Framework Convention on Climate Change (UNFCCC). These data are compiled using territory-based and production‑based principles following the Intergovernmental Panel on Climate Change (IPCC) guidelines. The primary data source is the Common Reporting Tables (CRT) submitted by Parties as of 25 June 2026. Since data is not available for all countries or all years, estimates were used to fill gaps. Coverage of official emissions data from CRT is as follows:

• OECD Members: For most OECD countries, official GHG emissions data are available from 1990 to 2023 or 2024. Exceptions include Colombia and Costa Rica, for which official data are available for 1990-2021, not that an updated inventory for Colombia is available but was not considered due to the cutoff date in this publication, and Israel, for which official data are available for 1996, 2000 and 2003-2022. The last year of reported data is 2022 for Chile, Republic of Korea, Mexico and the United States.

• OECD Partners: Significant data gaps remain including major emitters. China has provided official data for seven years (1994, 2005, 2010, 2012 and 2014, 2020-21), while India has presented data for four years (1994, 2000, 2010 and 2016). There are also gaps for Peru (data unavailable from 1990-1999, 2022-24), Saudi Arabia (data available only for 2005, 2020-22), South Africa (data are missing for ten years between 1990 and 1999, as well as for 2023-24) and Indonesia (data are unavailable for 1990-99 and 2023-24). Thailand has reported data only for 1990 and 2000-22. For Argentina and Brazil, the latest year of officially reported data is 2022.

To address these data gaps and provide a more complete and consistent greenhouse gas (GHG) emissions database for the period 1990-2024, the OECD applies a transparent methodology (OECD, Forthcoming[1]). The approach is as follows:

• Official GHG inventory data are prioritised using the most recent submissions (CRT and then other inventories), as set out in Table A A.1. .

• Sector-specific proxy variables are used to estimate missing years. Proxy variables are derived from authoritative international datasets (see Table A A.2. ).

• Estimates are produced using a simple and transparent approach using growth rates from the sector-specific proxy variables (IPCC, 2006[2]).

This represents an evolution in the GHG approach from previous editions of the Climate Action Monitor, which had filled gaps using PRIMAP-hist (Cárdenas Rodríguez et al., 2024[3]).

Table A A.1. Prioritisation of official data sources for compiling GHG emissions time series

Priority	Data source
1	Common Reporting Tables (CRT) submitted to the UNFCCC
2	Non-CRT National Greenhouse Gas Inventory Submissions (only for countries not submitting CRTs)
3	For CO2 LULUCF fluxes the following sources as been used as compiled in the dataset LULUCF data based on National GHG inventories (NGHGI DB) | Zenodo based on the methodology in ESSD - Carbon fluxes from land 2000–2020: bringing clarity to countries' reporting: National Communications (NC) Submissions under the Reducing Emissions from Deforestation and Forest Degradation (REDD+) framework Nationally Determined Contributions (NDC) Biennial Transparency Reports (BTR) Biennial Update Reports (BUR) BTR and BUR were also used in some additional ad-hoc in cases (e.g. CRT submission in irregular format)

Table A A.2. Proxy variables used to estimate missing data by sector

Sector	Proxy variable source
Energy	International Energy Agency (IEA) Greenhouse gas emissions estimates matching the energy module of 2006 IPCC Guideline for CO2, CH4 and N2O (IEA, 2025[4]).
Industrial Processes and Product Use (IPPU)	EDGAR emissions database for CO2, CH4, N2O, fluorinated gases (European Union 2025 and European Commission, 2025[5]).
Agriculture	FAOSTAT “Emission totals–IPCC Agriculture–FAO Tier 1” for CH4 and N2O (FAO, 2023[6]). EDGAR emissions database for CO2 emissions.
Land Use, Land-Use Change and Forestry (LULUCF)	FAOSTAT “Emission totals–LULUCF-Tier 1” for N2O, and CH4 (FAO, 2023[6]).
Waste	EDGAR emissions database for CO2, CH4, N2O (European Union 2025 and European Commission, 2025[5]).

Note: CO₂: Carbon dioxide, CH₄: Methane, N₂O: Nitrous oxide.

GHG emissions have been converted using Global Warming Potentials (GWP) from the fifth IPCC Assessment Report (AR5).

Global GHG emissions estimates

To estimate global GHG emissions, estimates of fuel combustion from international aviation and shipping (collectively referred to as international bunkers) and a LULUCF adjustment are needed. Emissions from international bunkers are sourced from EDGAR. The CO₂ LULUCF bookkeeping component uses data from (Friedlingstein et al., 2025[7]), following the approach used by (Olhoff, 2026[8]).

Historical global GHG emissions are calculated as:

${GHG}_{World}=\mathrm{ }{Country\mathrm{ }GHG}_{\mathrm{ }Including\mathrm{ }LULUCF}+\mathrm{ }{International\mathrm{ }Bunkers}_{}+LULUCF\mathrm{ }Adjustment\mathrm{ }$

Table A A.3. Detailed estimates of current and target GHG emissions levels

Gt CO₂e

	2024	2030	2035	2050
Global emissions if targets achieved	55.3	55 (51-59)*	52 (52-61)*	21.6 (20.5-22.6)
LULUCF adjustment	7.4	7.8	7.8	7.8
? LULUCF bookkeeping (outside inventories)***	4.6	5.0	5.0	5.0
? LULUCF inventories (last 10 years average)	-2.8	-2.8	-2.8	-2.8
International bunkers	1.4	1.0	0.8	0.0
Total countries (in GHG Inventories incl. LULUCF)	46.5	42 (38.1-43.9)	37.4 (35.5-41.2)	13.8 (12.7-14.8)
OECD	12.8	10.2	8.6	2.5 (0.6-5.9)
OECD Partners	23.1	20.8**	19.3**	4.9
1.5°C Consistent*		33 (26-34)	25 (20–27)	8 (5-13)
Below 2°C (66% chance)*		52 (45-58)	45 (28–53)	22 (3-30)

Note: *Sourced from (Olhoff, 2026[8]). The estimate found in (Olhoff, 2026[8]) for projected emissions in 2030 under Unconditional NDCs has been proportionally adjusted to align with the World emissions estimate.

**Excludes Saudi Arabia since its 2030 NDC cannot be quantified.

***Projected values use the average of the last ten years using Global Carbon Budget 2025.

GHG emissions targets

To enable comparison of countries’ NDC emissions targets, the OECD developed a methodology to estimate GHG emissions targets for 2030 and 2035 as physical emissions targets (Pizarro et al., 2024[9]). The methodology is as follows:

• If the country NDC target is defined in physical terms (i.e. tonnes of CO₂e), the target is maintained.

• For targets expressed in other forms (e.g. percentage reduction from a base year), transformations are applied to country-level data to derive 2030 and 2035 emissions levels in physical terms. These include adjustments for GDP, population and other transformations presented in (Pizarro et al., 2024[9]).

Countries' NDC targets are not directly comparable due to differences in coverage of sectors, gases and GWP. To enable comparability, emissions and targets were adjusted to AR5 Global Warming Potential (GWP) and covering all sectors and GHGs as follows:

• Physical targets are adjusted to AR5 GWP by multiplying the original target by the ratio of the total 2025 GHG emissions (AR5) over the GHG emissions within the NDC scope.

• For cases where targets exclude LULUCF, the target reduction is applied to total emissions excluding LULUCF and the country’s 2020-2024 LULUCF value is projected forward to the target year. The five-year average is applied rather than a single year (i.e. 2024) due to high annual variability of the LULUCF sector.

• GHG emissions outside of scope are imputed. This applies to China only as it uniquely covers CO₂ in its NDC. To this end, non-CO2 gases are projected within a range.

• For the United States, 2030 and 2035 physical emissions rely on the country’s NDCs sourced from the UNFCCC registry. Although these targets are no longer in force following the country's withdrawal from the Paris Agreement, they are used as a means of projecting future emissions.

Global emissions under unconditional NDC scenarios for 2030 and 2035 are taken from (Olhoff, 2026[8]) and adjusted proportionally to align with the global emissions estimates derived using the methodology described above.

Emissions in 2050 emissions were projected based on the assumption of countries achieving their net-zero targets as proposed. Emissions for countries without a net-zero target were assumed to be at the same level as 2024, with a range of +/- 10% (e.g. Iran, Azerbaijan and others).

Moreover:

• EU-27 countries were considered as a bloc that reaches climate neutrality by 2050, as per the EU Climate Law; individual countries’ targets differ since some do not have a net-zero target.

• Emissions for countries with a net-zero target later than 2050 are estimated based on a linear trajectory to their target year (e.g. China by 2060 and India by 2070).

• Estimates of residual emissions in 2050 were derived for countries with incomplete net-zero target gas scopes (e.g. CO2-only).

• For the United States, 2050 projected emissions are based on current emissions trends, previous NDC submissions to the UNFCCC (no longer in force) and the country's former net-zero commitment.

• Emissions were adjusted based on differences in LULUCF estimates based on (Olhoff, 2026[8]), and these differences were assumed to remain constant through 2050.

• International aviation and shipping are assumed to reach zero emissions by 2050 as per international agreements by the International Air and Transport Association and the International Maritime Organization. For simplicity, this reduction is assumed to be linear from 2024 to 2050, however, it is important to note that for international shipping per the 2023 IMO GHG Strategy: the current net-zero target by 2050 and the indicative GHG checkpoints for 2030 and 2040 were all modelled and assumed to follow an S-curve trajectory.

• 2030, 2035 and 2050 emissions consistent with 1.5°C and 2°C increase pathways are sourced from (Olhoff, 2026[8]).

Targets monitoring

In this edition, visualisations on distance to target indicators based on (Pizarro et al., 2024[9]) are used to provide insights on whether countries are on track to meet their climate targets over different time horizons: the NDC Delivery Gap and the 2050 Targets Alignment Gap. For these calculations, a base year of 2019 was used, the year when countries were formulating their NDCs, prior to the temporary drop in emissions recorded during the COVID-19 pandemic.

These are calculated as follows:

NDC Delivery Gap:

$t=measurement year$, $T=NDC target year$,

${{ NDC Delivery Gap}_t}^T= {GHG emissions}_t-{{Linear trend to NDC target}_t}^T$

${{ Percentage NDG Delivery Gap}_t}^T= \left(\frac{{{ NDC Delivery Gap}_t}^T}{{{Linear trend to NDC target}_t}^T}\right)\times 100$

2050 Targets Alignment Gap:

${{ 2050 Targets Alignment Gap}_t}^T= {{Linear trend to NDC target}_t}^T-{Linear trend to 2050 target}_t$

${{ Percentage 2050 TAG}_t}^T= \left(\frac{2050{{ TAG}_t}^T}{{ Linear trend 2050 target}_t}\right)\times 100$