Joe Biden will become the first sitting U.S. president to set foot in the Amazon rainforest during a brief stop Sunday in the Brazilian city of Manaus, coming as the US is expected to scale back its commitment to combating climate change under the incoming administration of Donald Trump. The massive Amazon it's about the size of Australia stores huge amounts of the world's carbon dioxide, a greenhouse gas driving climate change, even as it's rapidly deforested. Biden is expected to take an aerial tour over part of the world's largest tropical rainforest, meet local and indigenous leaders and visit an Amazonian museum as he looks to highlight his commitment to the preservation of the region. The Biden administration announced plans last year for a $500 million contribution to the Amazon Fund, the most significant international cooperation effort to preserve the rainforest, primarily financed by Norway. So far, the US government said it has provided $50 million, according to a July