ABSTRACT
Tropical rain forests are one of the world's most extensive biomes. There is growing evidence of the potential for major extinctions as a result of global climate change in the humid tropics. Contemporary environmental concerns have focused on the effects of deforestation on biological diversity, climate change, and atmospheric trace gases. F. Lowenstein suggested that tropical indigenous populations do not show any remarkable adaptations to heat stress but enjoy comfortable lives in humid heat because of moderate levels of activity and sensible, low sodium diets. High humidity and high ambient temperatures present a problem to which human populations have responded by regulatory adjustments: thermal sweating, minimal use of clothing, locating settlements on a rise of ground, and scheduling activities appropriately to reduce the heat load. The impacts of climate change on tropical forests are complex, with rising levels of carbon dioxide increasing productivity, while increased temperatures and drought diminish it.
