WASHINGTON (AP) — President Joe Biden is convening a coalition of the willing, the unwilling, the desperate-for-help and the avid-for-money for a two-day summit aimed at rallying the world’s worst polluters to do more to slow climate change. Biden’s first task when his virtual summit opens Thursday is to convince the world that the United States is both willing and able to meet an ambitious new emissions-cutting pledge. Success for Biden in the summit of 40 world leaders will be making his expected promise to halve U.S. coal and petroleum emissions believable enough to persuade other powers to make big changes of their own.