How is man affecting the rainforest?

Answer 1

Often described as the Earth's lungs, only in reverse, the tropicalrainforest's take in vast quantities of carbon dioxide (a poisonous gas which mammals exhale) and through the process of photosynthesis, converts it into clean, breathable air. In fact, the tropical rain forests are the single greatest terrestrial source of air that we breathe.
What's truly amazing, however, is that while the tropical rainforests cover just 2% of the Earth's land surface, they are home to two-thirds of all the living species on the planet. Additionally, "nearly half the medicinal compounds we use every day come from plants endemic to the tropical rainforest." If a cure for cancer or AIDS is to be found, it'll almost certainly come from the tropical rainforests.
Norman Myers, in his book, The Primary Source, writes that "tropical rainforests are the Earth's oldest continuous ecosystems. Fossil records show that the forests of Southeast Asia have existed in more or less their present form for 70 to 100 million years. The intensity of life forms is extraordinary: on the order of 1,000 species per square kilometer. By comparison, here in North America, we might only find 100 species in the same space." (2)
The largest rainforests are found in the Amazon Basin of South America, in Western African countries that skirt the equator, as well as South Pacific countries such as Indonesia and the Philippines. Smaller tracts of rainforests exist throughout Central America, parts of Mexico and Hawaii, as well as other islands of the Pacific and Caribbean.
Circling the Earth's equator like a belt, the tropical rainforests maintain a near constant temperature of 80 degrees Fahrenheit and receive anywhere from 160 to 400 inches of rain per year. These favorable weather conditions allow all life forms to flourish year- round. Furthermore, by virtue of their location, the tropical rainforests were spared the extreme loss of life that characterized other regions of the globe during the ice ages. These two factors help explain why the tropical rainforests are home to between 50 and 70 million different life forms.
Tragically, the tropical rainforests are being destroyed at an alarming rate. According to Rainforest Action Network, more than an acre-and-a-half is lost every second of every day (refer to the entries below to see, quantitatively, what that translates into). That's an area more than twice the size of Florida that goes up in smoke every year! "If present rates of destruction continue, half our remaining rainforests will be gone by the year 2025, and by 2060 there will be no rainforests remaining."
Every second . . we lose an area the size of two football fields!
Every minute . . we lose an area 29 times the size of the Pentagon!
Every hour . . . we lose an area 684 times larger than the New Orleans Superdome!
Every day . . . we lose an area larger than all five boroughs of New York City!
Every week . . . we lose an area twice the size of Rhode Island!
Every month . . .we lose an area the size of Belize!
Every year . . . we lose an area more than twice the size of Florida!
At the very least, "with the destruction of the tropical rainforests, over half the plant and animal species on earth, as well as numerous indigenous cultures will disappear forever."(2) If strong and decisive action is not taken immediately to reverse the destruction of this vital ecosystem, the consequences will be catastrophic. In fact, many scientists agree that the earth could very well become uninhabitable for virtually every living species, including humans!
We've consulted some knowledgeable experts in the field of tropical rainforest conservation and come up with some sobering facts that will lend credence for taking immediate action to save the last remaining tropical rainforests. And what might happen if we don't.
B I O - D I V E R S I T Y
. . . "a typical four-mile square mile patch of rainforest contains as many as 1,500 species of flowering plants, 750 species of trees, 125 mammal species, 400 species of birds, 100 species of reptiles, 60 species of amphibians, and 150 different species of butterflies."
. . . "there are more fish species in the Amazon river system than in the entire Atlantic Ocean."
. . . "a single rainforest reserve in Peru is home to more species of birds than the entire United States."
. . . "at least 1/3 of the planet's bird species live in the Amazon rainforest."
. . ."the Andean mountain range and the Amazon jungle are home to more than half of the world's species of flora and fauna."
. . . "at least 1,650 rainforest plants can be utilized as alternatives to our present fruit and vegetable staples."
. . . "37% of all medicines prescribed in the US have active ingredients derived from rainforest plants."
. . . "70% of the plant species identified by the US National Cancer Institute as holding anti-cancer properties come from rainforests."
. . . "90% of the rainforest plants used by Amazonian Indians as medicines have not been examined by modern science."
. . . "of the few rainforest plant species that have been studied by modern medicine, treatments have been found for childhood leukemia, breast cancer, high blood pressure, asthma, and scores of other illnesses."
. . . "a hectare (2.471 acres) of rain forest absorbs one ton of carbon dioxide (CO2) per year."
. . . conversely, "the clearing and burning of the world's rain forest accounts for 20-25% of the CO2 emitted into the atmosphere by man. It therefore could play a significant role in any so called "greenhouse effect" underway in our atmosphere."
THE COST OF RAIN FOREST DESTRUCTION
. . . "almost half of the world's original four billion acres of rainforest are now gone. The lost area equals the combined size of Washington, Idaho, California, Nevada and Arizona."
. . . "in 1500, there were an estimated six to nine million indigenous people inhabiting the tropical rainforests of Brazil. By 1900, that number had dropped to a million. Today, there are less than 250,000 indigenous people left in Brazil."
. . . "man has recently increased nature's "normal" extinction rate by 10,000%. Most of this increase is taking place in the rainforests."
. . . "by conservative estimates, 9,000 species are going extinct each year, most of them from the rainforests."
. . . "we are presently experiencing the largest mass extinction since the demise of the dinosaurs 65 million years ago; only this time it's occurring at a much faster rate."

Answer 2

Man is affecting the rainforest through deforestation, primarily for agriculture, logging, and infrastructure development. This leads to loss of biodiversity, habitat destruction for wildlife, and contributes to climate change. Man also impacts the rainforest through mining, hunting, and climate change-induced alterations in rainfall patterns.