The world’s tropical rain forest is located in South and Central America, Africa, Asia and Australia. It is the home for about half of all animal and plant species in the world. Also over a quarter of all modern medicine come from plants found in this type of forest. It is often called “the world’s largest pharmacy”. Vast amounts of the worlds carbon dioxide is stored in these forests. Therefore deforestation would lead to the release of this carbon into the atmosphere accelerating global warming.
The biggest threat to tropical rain forest is deforestation. Deforestation is currently affecting all types of forests but it is affecting tropical rain forests the most because of the demand for tropical timber and developing countries, such as Brazil clearing land for agricultural use. It is said that about half of the total amount of tropical rain forest that once covered the Earth is remaining. It is estimated that by 2030 only 10 percent will be remaining.
http://earthobservatory.nasa.gov/Library/Deforestation/deforestation_update5.html