The United States can achieve a 65% cut in emissions by 2035 if it adopts ambitious climate policies in its next Nationally Determined Contribution (NDC), concludes a new study that points to high-impact possibilities in electricity generation, transportation, and buildings.
Countries are due to update their NDCs—the climate action plans they submit as part of their obligations under the Paris Agreement—over the next year. The recent study assesses how far the U.S., as the world’s largest economy and second-largest greenhouse gas (GHG) emitter, can push its emissions reduction if it adopts more ambitious policies.
The focus of the analysis—published with open access by the leading journal Nature—is to chart “a plausible, high-ambition emissions reduction pathway,” the researchers state.
“Despite limitations, our analysis provides valuable information on the magnitude and variety of actions needed to set a U.S. 2035 NDC target that will be both sufficiently ambitious and, though likely challenging, also plausible to achieve.”
The researchers did their analysis using an integrated assessment model that projects the outcome of emissions reduction policies at state and national levels, including key legislation like the Biden administration’s Inflation Reduction Act (IRA). They projected emissions under both a “current policies scenario” and a “high-ambition scenario.”
While current policies were found to be on track to cut 40% of U.S. emissions by 2030 and 44% by 2035. The high-ambition scenario delivered reductions of 53% by 2030 and 65% by 2035.
Additional measures that made up the difference include:
• A full phaseout of unabated coal-fired electricity generation by 2030;
• Accelerated zero-emission vehicles (ZEV) adoption for light-duty vehicles, buses, and freight trucks;
• Zero-emission appliance standards;
• A methane fee that covers all sectors;
• Extensions of the existing IRA tax credits.
In both scenarios, the electricity sector accounted for the largest emission reductions and the transportation sector the second-largest. Significant reductions were also noted in the buildings sector.
The study also assessed emissions cuts from two carbon dioxide removal (CDR) technologies, including direct air capture (DAC) and biomass energy with carbon capture and storage (BECCS).
But while the study finds that CDR technologies “will almost certainly be required to offset residual emissions to reach net zero by 2050,” the authors also caution about unrealistic estimates of CDR levels that “can risk inadequate near-term mitigation and lead to large temperature overshoots.”
They say their study includes deploying “non-trivial amounts of CO2 removals from DAC and BECCS, which will require significant scale-up from today’s levels, though our numbers are conservative compared to estimates from other studies.”
They add that the research couldn’t incorporate different political, social, and behavioural factors that could “create uncertainties around uptake of our modeled policies,” such as “governance structures, lack of public support, and industry and interest group opposition could hinder efforts to enact robust climate policies.”
