The United States formally exits the Paris climate accord
The world's second-largest emitter became the only nation to leave the landmark agreement, though the move would prove short-lived.
The United States formally withdrew from the Paris climate agreement this November, becoming the only country in the world to leave the landmark 2015 accord, in a move that dismayed climate advocates and allies even as its practical effect proved short-lived.
The withdrawal, which had been announced years earlier and took effect after a mandatory waiting period, removed the world's largest historical emitter and second-largest current emitter from the global pact under which nearly every nation had pledged to limit its greenhouse gas emissions.
The exit was widely criticised as a abdication of leadership on one of the defining challenges of the age, and it complicated international efforts by removing the diplomatic and financial weight of the United States from the collective endeavour.
Yet the move's timing rendered it largely symbolic. It took effect just as a presidential election was being decided, and the incoming administration had pledged to rejoin the accord immediately upon taking office, meaning the formal absence would last only months.
In the interim, many American states, cities and businesses had pledged to continue pursuing the goals of the agreement regardless of federal policy, under coalitions declaring "we are still in." The episode underscored the vulnerability of long-term climate commitments to the shifting winds of domestic politics, and the resilience of action at other levels of government and in the private sector even when national leadership faltered.