The United States must implement all its currently proposed climate policies, along with additional measures, in order to meet its emissions reduction pledges as part of the Paris Agreement, reports a paper published online this week in Nature Climate Change.

President Barack Obama formally entered the United States into the Paris Agreement earlier this month. It commits the United States to reducing emissions by 26-28 % of 2005 levels by 2025, as part of its intended nationally determined contribution (INDC).

Jeffrey Greenblatt and Max Wei analysed whether the United States’ current range of proposed and implemented policies and laws (spanning the energy, transport agriculture and building sectors) were enough to meet the goal. They find that the United States will miss its INDC target by 551 to 1,805 million tons of CO2 equivalent (MtCO2e) if it continues only with its already-implemented policies and by 340 to 1,586 MtCO2e if it also implements its proposed policies. If the United States implements all possible policies in the pipeline (including those that have only been announced or yet to be formalized), there is a chance it will hit the INDC goal, but the authors note that this relies on favourable future policymaking conditions. As such, additional measures will likely be required to ensure US greenhouse gas emissions meet the 2025 INDC target.