The Amazon basin (equatorial) - the effects on tropical climate.
The Amazon basin in South America, vegetated by tropical rainforest, lies within the equatorial climate zone and covers an area of some 8,235,430 km 2 mainly in Brazil. The Amazon River flows through the basin from its source high in the Andes towards its mouth in the Atlantic Ocean, and is the largest single source of freshwater runoff on Earth, representing 15-20% of global river discharge. At present the amazon rainforest acts as a carbon sink. It absorbs around 35% of the world’s annual carbon dioxide emissions and produces more than 20% of the world’s oxygen. It contains the greatest biodiversity on Earth, providing a habitat for more than half the worlds estimated 10 million species of plants animals and insects. Predicted impacts on climate change on this region include: An increase in temperature of 2-3 C by 2050 which is likely to result in increased rates of evapotranspiration and a more vigorous hydrological cycle. Sea temperatures are also expected to warm, particularly in the Pacific Ocean. This will have a knock on effect on the El Nino Southern Oscillation (ENSO), which is likely to occur more frequently.
A decrease in precipitation during the dry season (which can last up to 4 months of the year) is expected. Reduced rainfall and prolonged drought are features of an El Nino year and these will be experiences more frequently. It is possible that more intense rainfall will be experiences during the wet season.
Up to 40% of plant species may no longer be viable in the Amazon rainforest by 2080 if predicted climate changes occur. Large areas of the evergreen tropical rainforest may be succeeded by mixed forest and savannah grassland vegetation.
As the dry season lengthens trees will have more time to dry out so there is likely to be an increased incidence of...
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