On January 20, 2021, newly inaugurated President Joe Biden signed an executive order to rejoin the Paris Agreement, fulfilling a campaign promise to restore U.S. leadership in global climate efforts. The rejoining process was completed on February 19, 2021, marking a renewed commitment by the U.S. to work with other nations to combat climate change and achieve the goals set forth in the agreement.

On November 4, 2020, the United States officially withdrew from the Paris Agreement, completing the process initiated by President Donald Trump in 2017. This marked the first time a country had withdrawn from the accord. The withdrawal was seen as a significant setback for global climate efforts, given the U.S.'s role as a major emitter and its influence in international climate policy.

On June 1, 2017, U.S. President Donald Trump announced that the United States would withdraw from the Paris Agreement, citing concerns about the economic impact of the accord. This decision was met with widespread criticism both domestically and internationally, as the U.S. was the world's second-largest emitter of greenhouse gases at the time. The withdrawal process could not be completed until November 2020, due to the agreement's terms.

The Paris Agreement officially entered into force on November 4, 2016, just 30 days after at least 55 countries, accounting for at least 55% of global greenhouse gas emissions, ratified the agreement. This rapid entry into force was unprecedented for an international agreement of its kind, reflecting the global urgency to address climate change and the widespread support for the agreement's goals.

On April 22, 2016, Earth Day, the Paris Agreement was opened for signature at a ceremony held at the United Nations Headquarters in New York City. A record number of 175 countries signed the agreement on the first day, demonstrating a strong global commitment to addressing climate change. This event underscored the urgency and importance of international cooperation in combating climate change.

The Paris Agreement was adopted on December 12, 2015, during the 21st Conference of the Parties (COP21) to the United Nations Framework Convention on Climate Change (UNFCCC) held in Paris. The agreement marked a historic turning point for global climate action, as it was the first universal, legally binding climate deal. It aimed to limit global warming to well below 2 degrees Celsius above pre-industrial levels, with efforts to limit the temperature increase to 1.5 degrees Celsius.