President Joe Biden pledged Tuesday to "double" United States (US) contributions towards a goal of mobilizing US$100 billion for countries hardest-hit by global warming, a move hailed as a rare piece of good news in the climate crisis.Experts said the announcement would take the American contribution to the commitment, made by developed countries ahead of the 2015 Paris agreement, to approximately US$11.4 billion annually."This will make the United States a leader in public cli