The impact of policy and model uncertainties on emissions projections of the Paris Agreement pledges
Tracking progress towards the Paris Agreement climate goal requires understanding the 2030 emission levels implied by countries' National Determined Contributions (NDCs). However, key uncertainties and assumptions impact greenhouse gas (GHG) emission projections implied by the NDCs. This study analyses this impact, both globally and for major emitting countries. We find that the assessed uncertainties markedly affect global GHG emission projections. Full achievement of NDC targets is estimated to result in a range of 46–60 GtCO2eq by 2030 (median estimate: 53 GtCO2eq).
The most important contributing factor to the uncertainty in measuring historical emissions, including land-use, is reflected by different datasets. There are two equally important contributing factors globally: socio-economic baseline uncertainty, and uncertainty about the emissions implied by current policies in the case NDCs are less ambitious than the former.
Overall, the impact of policy uncertainty (i.e. uncertainty resulting from conditionality of or ranges in NDC targets and uncertainty in emissions resulting from current policies) is equally as important as model/technical uncertainty (i.e. uncertainty in historical emissions and socio-economic baseline variations).
This new insight is important for decision-makers and researchers because a larger share of the total uncertainty is now attributable to aspects that can be influenced by policy decisions compared to previous analyses of NDC uncertainty.
Authors
Specifications
- Publication title
- The impact of policy and model uncertainties on emissions projections of the Paris Agreement pledges
- Publication date
- 5 May 2023
- Publication type
- Article
- Publication language
- English
- Magazine
- Environmental Research Letters
- Issue
- 18 (2023)
- Product number
- 5219
