The Amazon rainforest produces more than 20% the world's oxygen supply. The Amazon River pushes so much water into the Atlantic Ocean that, more than one hundred miles at sea off the mouth of the river, one can dip fresh water out of the ocean. The volume of water in the Amazon river is greater than the next eight largest rivers in the world combined and three times the flow of all rivers in the United States.
According to wikipedia "The main sources of deforestation in the Amazon Rainforest are human settlement and development of the land. Between 1991 and 2000, the total area of forest lost in the Amazon Rainforest rose from 415,000 to 587,000 km², an area more than six times the size of Portugal, with most of the lost forest becoming pasture for cattle. In February, 2008, the Brazilian government announced that the rate at which the Amazon rainforest is being cut down has increased significantly over the past few months. During the last five months of 2007, more than 3,200 sq. kilometers (an area equivalent to the size of the state of Rhode Island, in United States) was deforested during a time when deforestation would normally drop...At the current rate, in two decades the Amazon Rainforest will be reduced by 40%..."
Bet you didn't know.