Still possible to limit global temperature rise to 1.5°C
Associate Professor Mikael Karlsson, senior lecturer in climate leadership at Uppsala University and co-author of the study. Photo: Tobias Sterner
It is still possible to limit global warming to the Paris Agreement goal of 1.5°C above pre-industrial levels – assuming that certain countries shoulder greater responsibility for climate efforts. This is demonstrated by a group of researchers from Uppsala University, Stockholm University and Chalmers University of Technology in a new study published in Nature Communications.
“Our study gives hope prior to the UN’s climate conference, COP29 in Baku. It is possible to achieve international climate goals, but we demonstrate that the EU and 17 countries need to upgrade their goals and policy instruments and, not least, increase their funding for climate initiatives,” says Associate Professor Mikael Karlsson, senior lecturer in climate leadership at Uppsala University and co-author of the study.
The study proposes a new indicator, additional carbon accountability, to quantify each country’s responsibility to mitigate or remove CO2 in addition to achieving its own targets.
Based on national shares
The indicator is calculated based on each country’s equal cumulative per capita share of the global carbon budget for limiting the global temperature rise to 1.5°C above pre-industrial levels. Generally speaking, high-income countries have a large historical carbon debt, while several upper-middle-income countries will have higher emissions in the future.
Based on the new indicator, 18 high-income countries (with the EU treated as an aggregate unit) and upper-middle-income countries should be accountable for increasing their ambitions. Four of 18 countries with additional carbon accountability should theoretically be able to fulfil their entire additional carbon accountability with stricter domestic emission reductions, while 14 have greater accountability than their planned future emissions, meaning that they would need to contribute to reducing emissions or increasing carbon capture in other countries.
The US and China have the largest additional carbon accountability
The United States and China have by far the largest additional carbon accountability. The United Arab Emirates, Russia, Saudi Arabia and the US have the largest per capita accountability.
The European Union needs to both achieve its own targets for reduced emissions by 2030 and net-zero emissions by 2050 and implement further major reductions in emissions and increased carbon capture both within the EU and elsewhere.
“It is high time for the EU to upgrade both its goals and its climate policy instruments, while at the same time increasing funding for measures in other countries. This is the key message that the EU should be promoting at COP29,” says study co-author Mikael Karlsson of Uppsala University.
Publication
Hahn, T., Morfeldt, J., Höglund, R., Karlsson, M., & Fetzer, I. (2024). Estimating countries’ additional carbon accountability for closing the mitigation gap based on past and future emissions. Nature Communications 15, 9707.