• Energy Research
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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.

This article reviews climate change mitigation policies implemented in five major emitting economies: China, the European Union, India, Japan and the United States. It analyses their historical performance in terms of energy system and greenhouse gas emissions indicators. In cases where policies aim to reduce future emissions, their target performance levels are assessed. The review centres on the sectors of electricity generation, passenger vehicles, freight transport, forestry, industry, buildings, agriculture, and oil and gas production. Most focus countries have implemented successful policies for renewable energy, fuel efficiency, electrification of passenger vehicles, and forestry. For other sectors, information is limited or very heterogeneous (e.g. buildings, appliances, agriculture) or there are few comprehensive policies in place (e.g. industry). The article further presents an explorative emissions scenario developed under the assumption that all countries will replicate both the observed trends in sector-level indicators and the trends that policies for future emissions reductions aspire to achieve. It shows that the global replication of sector progress would reduce greenhouse gas emissions by 2030 by about 20% compared to a current policies scenario. All countries analysed would overachieve the emissions reduction targets in their post-2020 climate targets. However, the resulting reduction in global emissions by 2030 would still not be sufficient to keep the world on track for a global cost-effective pathway that keeps temperature increase below 2°C. The findings of this study emphasise the need for transformative policies to keep the Paris Agreement temperature limit within reach.

Under the Paris Agreement, countries committed to a variety of climate actions, including post-2020 greenhouse gas (GHG) emissions reduction targets. This study compares projected GHG emissions in the G20 economies under current climate policies to those under the GHG targets outlined in the nationally determined contributions (NDCs). It is based on an assessment of official governmental estimates and independent national and global studies. The study concludes that six G20 members (China, India, Indonesia, Japan, Russia and Turkey) are projected to meet their unconditional NDC targets with current policies. Eight members (Argentina, Australia, Canada, the European Union, Republic of Korea, South Africa and the United States) require further action to achieve their targets. Insufficient information is available for Saudi Arabia, and emission projections for Brazil and Mexico are subject to considerable uncertainty. The study also presents high-level decarbonisation indicators to better understand the current progress towards meeting the NDCs – Saudi Arabia and South Africa were found to continue increasing both emission intensity per unit GDP and emissions per capita under current policies by 2030 from 2015 levels.