A multi-model study to inform the United States' 2035 NDC.

In 2025, countries are expected to submit a third round of nationally determined contributions (NDCs) that outline emission reduction goals for 2035. These new NDCs will be important for global alignment with the Paris Agreement's long-term goals. Setting an ambitious and plausible 2035 NDC in the United States (US) could be crucial in motivating high levels of ambition globally. This study brings together four US modeling teams to show that an expanded set of federal and state policies beyond current policies could achieve economy-wide emissions reductions of 56-67% below 2005 levels by 2035. By contrast, current policies result in 34-44% reductions. These potential policies significantly close the gap relative to the official US pledge. They also imply 2-4 times increase in renewable capacity additions, 73-100% reduction in electricity generation from unabated fossil fuels, and 83-100% share of electric vehicles in new vehicles sales. This study provides a framework for decisionmakers to use modeling as an input to inform ambitious and plausible pledges.