On June 1, 2017, President Donald Trump announced that the United States would be leaving the Paris Agreement. In accordance with Article 28 of the agreement, member states cannot give notice of withdrawal until three years after the agreement’s start date in that country. On November 4, 2019, the earliest possible date, the administration submitted its formal intention to withdraw. A year later, on November 4, 2020, the withdrawal went into effect, and the United States, which has cumulatively emitted more carbon into the atmosphere than any other country, became the first and only member state to withdraw from the Paris Agreement.

Despite the year-long waiting period to withdraw from the agreement, the process of returning to it is far more expedited. President Elect Joseph Biden has expressed his intent to immediately rejoin the agreement as soon as he is in office. Once the United States notifies the UN Framework Convention on Climate Change (UNFCCC) of its intention to rejoin, it will formally become a party to the agreement once again 30 days later. However, this does not mean that the U.S. can pick up where it left off in 2016 in the agreement. Negotiations and commitments have continued without significant U.S. involvement, and the Biden administration will need to set new emissions commitments for 2030, as well as rebuild credibility that has been lost in the last four years.

In November of 2021, the member states to the Paris Agreement will meet in Glasgow for COP26, the annual meeting of the UNFCCC which has been postponed by one year due to the ongoing COVID-19 pandemic. This meeting will include the first “global stocktake” outlined in the Paris Agreement. Under the original agreement, member states submitted “Intended Nationally Determined Contributions” (NDCs) outlining their commitments to reduce carbon emissions compared to a “business as usual” scenario. In five-year cycles, countries are supposed to assess their progress toward their goals and re-commit, ideally strengthening their commitments every five years. The first global stocktake, at the end of the first five-year cycle, was supposed to happen at COP26 in Glasgow in 2020. Now, due to the meeting’s postponement, it will happen in November of 2021. The ambition that the world shows in its renewed, strengthened commitments will indicate the trajectory of international climate action for years to come.

Under the Obama administration, the U.S. made a commitment to reduce carbon emissions by 26-28% of 2005 levels by 2025, a target that the country is not on pace to achieve. Biden has not yet announced his administration’s planned commitment to be made in Glasgow. However, he has announced an ambitious domestic climate platform, through which he plans to commit $1.7 trillion of federal investment in climate action over the next decade, and has expressed a goal of achieving a 100% clean energy economy and net-zero emissions by 2050.

A strong NDC from the Biden administration has the potential to leverage increased commitments from other big polluters, including China and India. Convincing these countries to increase their ambition is a focus of the Biden platform. In his first 100 days in office, he has expressed an intent to convene a global summit of the world’s major carbon-emitting nations. The goal of this summit will be to persuade these countries to join the United States in strengthening their national pledges. However, this may be a more difficult task if the U.S. itself has not yet announced its increased commitments.