Regional Climates and a Changing World

The Amazon basin hosts the largest expanse of tropical rainforest climate on the planet, sustained by the near-constant presence of the ITCZ and by intense year-round heating and rainfall. Remarkably, the Amazon generates a substantial portion of its own precipitation: enormous volumes of water evaporate and transpire from the forest canopy and are carried westward by the trade winds as vast plumes of atmospheric moisture, sometimes called flying rivers, which condense and fall again as rain further inland, in a cycle that repeats several times before the air mass reaches the Andes. This self-reinforcing water cycle also means that large-scale deforestation threatens not only local biodiversity but the region's own rainfall generation, with implications for both regional climate stability and the global carbon cycle, given the enormous carbon stock held in Amazonian vegetation and soils.