The United States has officially returned to the Paris climate pact—just 107 days after Donald Trump threw his toys out of the stroller and withdrew from the international accord. President Joe Biden signed an executive order within hours of his inauguration last month that reversed the withdrawal that Trump ordered in 2019, but that only came into effect on Nov. 4 last year. World leaders breathed a sigh of relief as the U.S. rejoined the agreement that promises to achieve net zero carbon emissions by the middle of this century. United Nations Secretary General António Guterres said the official U.S. re-entry “is itself very important” as a symbolic act—but stressed that it must be followed up by action. “We hope they will translate into a very meaningful reduction of emissions and they will be an example for other countries to follow,” Guterres said. More than 120 nations, including the world’s worst emitter—China)—have signed up.