Well tuned, the Amazon’s hydrological
engine plays a major role in maintaining the global and regional climate.
Water released by plants into the atmosphere through evapotranspiration
(evaporation and plant transpiration) and to the ocean by the rivers, influences world climate and the circulation of ocean currents
. This works as a feedback mechanism, as the process also sustains the regional climate on which it depends.
What is happening in the Amazon?
But scientists are noticing something disturbing in the Amazon rainforest - the hydrological engine is beginning to fail. Two major factors are at play.
One factor is the El Niño Southern Oscillation (ENSO)
, a climatic phenomenon which influences much of the climatic variability in Latin America. Although ENSO events are a natural occurrence, human-induced climate change is expected to increase their frequency in the future.
ENSO is associated with dry conditions in northeast Brazil, the northern Amazon, the Peruvian-Bolivian Altiplano
, and Pacific coast of Central America. Meanwhile, southern Brazil and northwestern Peru have exhibited unusually wet conditions during ENSO events.
Another factor is deforestation, which in addition to removing forest cover causes a dramatic change in rainfall patterns and distribution. These findings imply that current deforestation in the Amazon has already altered the regional climate. They also support previous reports of increased shallow cloudiness over deforested areas.