AFTER the United States officially withdrew from the 2015 Paris Agreement, officials, analysts and campaigners said the departure dealt a blow to global climate diplomacy and the battle to curb rising planet-heating emissions. But, they noted, many American cities, states and companies continue to lead a push to meet U.S. commitments under the Paris accord, aimed at heading off the worst impacts of wild weather and rising seas by reining in temperature rise. And they said it would be relatively simple for Washington to rejoin the pact should Democratic presidential challenger Joe Biden win the race for the White House,…