Enhancing Global Ambition for 2035: Assessment of High-Ambition Country Pathways

Cui, R., M., Borrero, C., Bertram, J., Behrendt, A., Rader, M., George, D., Churlyaev, A., Kreis, J., Lou, A., Miller, X., Fu, T., Tibebu, K., O’Keefe, X., Li, M., Zhu, A., Zhao, C., Squire, N., Hultman, J., Snarski, B., Buddi (2024). Enhancing Global Ambition for 2035: Assessment of High-Ambition Country Pathways. Center for Global Sustainability, University of Maryland.

Based on these assessments, the report concludes with the following key findings:

• Globally, the High Ambition country pathways can deliver a 35% reduction in total GHG emissions by 2035 from the 2023 level, compared to a 7% reduction in 2030 with existing country NDCs, and a 12% reduction by 2035 if countries follow the Delayed Transition pathways. 
• Following the High Ambition pathways to net-zero CO2 emissions with targeted non-CO2 abatement leads to a peak temperature of 1.7°C with median likelihood; the additional CO2 emissions from High Ambition to Delayed Transition alone would increase the peak temperature to 1.8°C, even with a very optimistic post-2030 trajectory after the delay to net zero.
• Drawing down the temperature overshoot and returning to 1.5°C is a massive challenge with uncertain feasibility in both technological and geophysical aspects of negative emissions, and adding a tenth of a degree °C makes the return nearly impossible.
• Across sectors, electricity generation contributes to the largest CO2 emissions reductions for most countries through 2035, globally increasing wind and solar capacity by tenfold and more than halving unabated fossil power generation from the 2020 levels. Contributions from industry, transport, buildings, and land sectors vary across countries based on existing emissions profiles.
• Targeted methane abatement in oil and gas, coal, and waste sectors can drive down global methane emissions by 35% from 2020, which accounts for nearly 40% of total GHG reductions between 2020 and 2035 if measured in its 20-year global warming potential.
• Key emitting countries are categorized into three groups, based on current emission trends, existing targets, and the potential to mitigate under the High Ambition pathways. 
  • Group A countries with already decreasing emissions, existing 2030 commitments on absolute reductions from a base year and net-zero emissions by 2050 can deliver about 60 to 70% reduction in total GHG emissions from the NDC base year (or around 50% from 2023) by 2035; 
  • Group B countries with recent or immediate peak emissions before 2025 can deliver 30 to 40% reduction by 2035 from the peak level; and 
  • Group C countries with still growing emissions need to limit the growth and can deliver 10 to 20% reduction by 2035 from the estimated peak in a future year. 
• Moving from the High Ambition pathways to Delayed Transition, majority (nearly 85%) of the increased cumulative emissions between 2023 and net-zero occur in Group B and Group C countries; with further delay of emissions reductions in Group B countries and emissions peak in Group C countries beyond 2030, even larger peak temperatures exceeding 1.8°C would become inevitable. 
• Despite different climate governance and institutional structures across countries, subnational actors have large potential and can make important contributions to enhance and deliver national ambition. With policy authorities in key areas (such as land, waste, transportation), subnational actors can innovate and implement solutions and build broader partnerships to drive action and deliver social and economic benefits to the local communities.