Amazon Drought Linked to Hurricanes

The worsening drought in the Amazon has forced the Brazilian government to extend emergency warnings across the state.  The combined effects of global warming and deforestation have caused conditions of unprecedented significance.  The military has been activated to distribute supplies and medical aid to tens of thousands who have been impacted by the worst drought in Amazon history.

Fire may pose the biggest threat to the survival of the Amazon ecosystem. The Woods Hole Research Center has found that for every acre cleared and burned in the Amazon for cattle grazing or farming, at least another acre burns in ground fires under the forest canopy and/or is degraded by selective logging.  Deforestation reduces moisture in the air, increasing sunlight penetration onto land. It also prevents land and rivers from holding rain when it comes, causing excessive runoff and preventing the water table from increasing reserves.  Satellite images show that deforestation in the Amazon basin have been underestimated by at least 60%.  About 17% of the Amazon basin has been deforested over the past 30 years contributing to the drought condition.

It hasn't rained in the Amazon since August.  Many scientists believe hurricanes  affect weather in the Amazon because rising air in the north Atlantic, which fuels the storms, causes the air above the Amazon to descend, preventing cloud formation and rainfall.  Some scientists believe that global warming is the cause of the warmer water in the North Atlantic.  Previously droughts have been correlated to El Niños, the warming of waters in the Pacific, but this has not happened this year.

Dan Nepstadt, an ecologist from the Massachusetts-based Woods Hole Research Institute has commented on both of these explanations in several media accounts and has attributed both of them to being possible causes of the drought.

The military has been activated to distribute supplies and medical aid to tens of thousands who have been impacted by the drought. The drought which began in August has caused millions of fish to die in the tributaries that provide water, food and access to towns.  Low river levels have prevented residents from using boats, their only means of transportation, requiring government airlifts for their survival.  Four towns, with a population of 42,000, along with many smaller communities in the state of Amazonas, have been especially hard hit.

Resources:

"Amazon Drought Could Speed Climate Change", PeopleandPlanet.net, October 23, 2005
"Amazon Drought: Deforestation and climate change to blame", Environmental Data Interactive, October 21, 2005
"From Forest Fires to Field: How Forest Fires are Transforming the Amazon", NASA
"Amazon Drought Worst in Decades", Tech News, October 10, 2005
"Brazil Declares Disaster Areas in Amazon", CNN, October 10, 2005

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