The G20 emission projections to 2030 improved since the Paris Agreement, but only slightly

Abstract

Many years passed since the adoption of the Paris Agreement, which invites countries to determine their own contributions to climate change mitigation efforts. The Agreement does not offer a standard to measure progress but relies on a process of periodic stocktakes to inform ambition-raising cycles. To contribute to this process, we compare 2021 greenhouse gas emission projections up to 2030 against equivalent projections prepared back in 2015. Both sets of projections were prepared using the same bottom-up modelling approach that accounts for adopted policies at the time. We find that 2021 projections for the G20 as a group are almost 15% lower (approximately 6 GtCO₂eq) in 2030 than projected in 2015. Annual emissions grow 1% slower in the coming decade than projected in 2015. This slower growth mostly stems from the adoption of new policies and updated expectations on technology uptake and economic growth. However, around one-quarter of these changes are explained by the effects of the COVID-19 pandemic on short-term emissions and economic forecasts. These factors combined result in substantially lower emission projections for India, the European Union plus the UK (EU27 + UK), the Unites States, Russia, Saudi Arabia, and South Africa. We observe a remarkable change in South African projections that changed from a substantial increase to now a decline, driven in part by the planned phase-out of most of its coal-based power. Emissions in India are projected to grow slower than in 2015 and in Indonesia faster, but emissions per capita in both countries remain below 5 tCO₂eq in 2030, while those in the EU27 + UK decline faster than expected in 2015 and probably cross the 5 tCO₂eq threshold before 2030. Projected emissions per capita in Australia, Canada, Saudi Arabia, and the United States are now lower than projected in 2015 but remain above 15 tCO₂eq in 2030. Although emission projections for the G20 improved since 2015, collectively they still slightly increase until 2030 and remain insufficient to meet the Paris Agreement temperature goals. The G20 must urgently and drastically improve adopted policies and actions to limit the end-of-century warming to 1.5 °C.

Supplementary information: The online version contains supplementary material available at 10.1007/s11027-022-10018-5.

Keywords: Adopted policy scenario; Climate change mitigation; Climate policy; Greenhouse gas emissions; Paris Agreement; Stocktake.

Fig. 1

Approach to calculate change in 2030 absolute emissions per country between projections developed in 2015 (GHG₂₀₁₅) and 2021 (GHG₂₀₂₁) and estimate the contribution of COVID-19 to the change observed

Fig. 2

Change in 2030 absolute emission projections. Negative values indicate that projections developed in 2021 are lower than those from 2015. Values based on the middle of the projection range

Fig. 3

Emission trajectories developed in 2015 (orange) and 2021 (blue) for the G20. Mind the y-axis for each country graph. Emissions exclude LULUCF and are reported in AR4 GWP-100

Fig. 4

Emissions per capita trajectories developed in 2015 (orange) and 2021 (blue) for the G20 countries. Countries are sorted by emissions per capita levels in 2030. Emissions exclude LULUCF and are reported in AR4 GWP-100

Fig. 5

Emissions in 2030 compared to 2015 levels. The bars indicate the range of emissions for each set of projections. Positive numbers indicate an increase compared to 2015

Fig. 6

Average yearly change rate in GHG emission projections between 2021 and 2030. Emissions are expected to grow faster in most recent projections for Indonesia, Mexico, and Argentina