Rainforests and deforestation

Rainforests are complicated tropical ecosystems with extremely high levels of biodiversity. Occupying less than 6 percent of the Earth’s surface in the 2020s, they contain at least 50 percent of the world’s known plant and animal species and produce at least 20 percent of Earth’s oxygen. The rainforests were being destroyed at such an unprecedented rate in the early twenty-first century; however, if the trend continues, no sustainable tropical rainforests will remain by the middle of the twenty-first century.

Background

Tropical rainforests are the most complex ecosystems on Earth, consisting of interacting systems of vegetation and animal species so interdependent that distressing one part can cause unpredictable and often irreversible damage. In 2022, temperatures typically ranged from 21 to 30 degrees Celsius (70 to 85 degrees Fahrenheit), with annual rainfall of about 200 to 1,000 centimeters (80 to 400 inches) and average humidity between 77 and 88 percent. Rainforests contain a wider variety of tree species than any other region of the world, with an estimated 40,000 to 53,000 species populating tropical rainforests with 400 billion trees. Just one hectare (2.5 acres) may contain more than 100 species of tree. Each region is individually diversified, meaning that species found in one area may differ radically from those in another area several kilometers away.

The rainforests surrounding the Amazon basin in South America represent the last great contiguous expanse of tropical rainforest remaining in the world. Containing an estimated 30 percent of all species on Earth, the Amazon began being systematically devastated by human actions around 1960. Brazil held approximately 60 percent of the Amazon in 2023, which totaled around 40 percent of the country’s total land area. However, the rate of deforestation in the Brazilian Amazon experienced large increases and decreases in the twenty-first century. After destruction peaked at 27,772 square kilometers in 2004—the highest annual clearance rate since 1995—it increased again by 16 percent in 2014–15, although it remained at a historical low. In 2019, around 75,000 fires devastated the tree coverage, and in 2022, deforestation reached an all-time record with 1,500 square miles of destruction. While Brazil's Amazon rainforest say over 30 percent less deforestation in 2024 compared to 2023, deforestation remained detrimental.

The environmental, economic, and social consequences of large-scale tropical deforestation are numerous and severe. Rainforests are giant solar-powered engines that pump water, nutrients, and carbon dioxide through the biosphere. Water captured by vegetation is stored in vines and roots, from where it is slowly released to streams and rivers, continuing the evaporation cycle. When large tracts of rainforest are cleared, water cannot be readily stored, leading to alternate periods of drought and floods.

Rainforests consist of lush, abundant growth, but the soil is deficient in nutrients and only marginally fertile. Although organic materials decompose rapidly in warm, humid climates, heavy rains leach nutrients from the root zone. Plant life has adapted by rapidly ingesting the nutrients as they become available; most nutrients are stored in the vegetation itself, not in the soil. When the land is cleared for agriculture or livestock, the necessary crop-sustaining nutrients are depleted within a few growing seasons.

The biodiversity of the tropical rainforest is so immense that less than 1 percent of its millions of species have been studied by scientists for their active constituents and their possible uses. Experts estimated in 2022 that around 137 plant, animal, and insect species are lost every day (approximately 50,000 species per year) because of deforestation. As the rainforest species disappear, so do many possible cures for life-threatening diseases. If deforestation continues at current rates, nearly one-half of the world’s species of plants, animals, and microorganisms will be destroyed or severely threatened by the middle of the twenty-first century.

Rainforest Resources

In the twenty-first century, the Amazon rainforest covered an area of between 6.2 and 7.8 million square kilometers (3 million square miles), including the approximately 6.9 million square kilometers (2.7 million square miles) that make up the Amazon River basin. Almost two-thirds of the Amazon is located in Brazil, with the remainder covering parts of Bolivia, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname, and Venezuela. More than one-half of the world’s estimated 10 million species of plants, animals, and insects live in tropical rainforests; only between 1.4 and 1.8 million of these species had been named by 2024. The Amazon rainforest has the greatest diversity of plant species on Earth. According to National Geographic’s estimates, a 10 square kilometer patch of rainforest may host around 1,500 flowering plants, 750 species of trees, 400 species of birds, and 150 species of butterflies.

Approximately 80 percent of the developed world’s diet originated in tropical rainforests, including avocados, figs, oranges, lemons, grapefruit, bananas, guavas, pineapples, mangos, and tomatoes. Vegetables originating from the rainforest include corn, potatoes, rice, squash, and yams. Rainforest spices include black pepper, cayenne, cinnamon, cloves, and ginger. Other popular rainforest-derived foods include chocolate, sugarcane, coffee, vanilla, and cashews. At least three thousand different fruits are found in the rainforests; of these, only about two hundred are used in the Western world, while the forests' indigenous peoples make use of more than two thousand. Rainforest plants are rich in secondary metabolites, particularly alkaloids, which protect plants from disease and insect attacks and have medicinal benefits.

Tropical rainforests are important sources of genetic material for improving existing crop plants or breeding new varieties. As the population size of a species shrinks, genetic diversity shrinks in direct proportion, because as a species diminishes in number, genes disappear even if the species survives. A reduction of the gene pool renders a species less adaptable to changing environments and more susceptible to extinction, depriving future generations of potentially useful resources.

Without periodic infusions of new germ plasm, crops bred specifically for humans, such as coffee, bananas, and cocoa, cannot continue to produce high yields at low cost. As the products of generations of selective breeding, these crops continually require the amalgamation of new genetic material to maintain productivity and flavor, to counteract new diseases and insect strains, and to endure environmental stresses such as unusual cold or drought.

Several important crops, including cocoa, coffee, bananas, and sugarcane, have been saved from viruses and other pathogens by being crossbred with wild species that have acquired resistance naturally. Although crop diseases can be contained or eliminated by applying fungicides or pesticides, the cost is prohibitive. It is much less expensive, and more environmentally benign, to find a resistant strain of the same crop in one of the world’s remaining wild habitats.

Future contributions from wild germ plasm, in addition to breeding new disease-resistant varieties of crops, might include the creation of hybrid perennial varieties of annual crops, eliminating annual plowing and sowing. Another possibility may be new varieties of conventional crops that could survive in conditions or environments that are presently unsuitable, extending the plants’ cultivation range. Rainforests also provide opportunities for humans to develop and cultivate entirely new crops. Many of the world’s staples are not necessarily the best possible sources of nutrition and protein; they were merely the crops most easily cultivated by Neolithic humans.

Because the developed world consumes enormous quantities of sugar annually, there is an urgent need for a sweetening agent without the potentially undesirable side effects of synthetic sweeteners. Natural sweeteners found in common fruits are problematic because many people already consume more of these than is healthy. However, a new class of nonfattening natural sweeteners made of protein compounds has been identified. At least one thousand times sweeter than sucrose, and with no known detrimental side effects, these tropical sweeteners are viable replacements for the sucrose commonly added to food items.

Rainforests: Pharmacopeia to the World

There were an estimated ten million indigenous peoples living in the Amazon rainforest five centuries ago; in 2021, the Amazon region was populated by nearly 50 million Portuguese-speaking peoples and 1.5 million indigenous peoples, who occupy 28 percent of the total Amazon basin. As their homelands continue to be destroyed by deforestation, forcing them to leave, the key to finding new medicinal plants declines proportionately. Most shamans, with thousands of years of irreplaceable knowledge about medicinal plants, are at least seventy years old, and few have apprentices. Thus, when a rainforest shaman dies, it is as if a library has burned down; the failure to document this information is a tremendous economic and scientific loss to the industrialized world.

The twenty best selling drugs in the United States were derived from plants, as are around 40 percent of drugs sold in Western world pharmacies. Despite this, very few rainforest regions have been subjected to ethnobotanical analysis to identify and catalog the tropical biota. There are many undiscovered biodynamic compounds with unrealized potential for use in modern medicine residing in the rainforest, but to access the information, species must be preserved and studied. Curare, a plant extract found in various species of tropical vines, and derivatives thereof are used as muscle relaxants to supplement anesthesia during surgery. Quinine, from the cinchona tree, is used to treat malaria. The introduction of two drugs derived from the rosy periwinkle, a wildflower native to Madagascar, dramatically increased the likelihood of remission for a child with leukemia, from 10 percent in 1960 to 95 percent in 1997.

Rainforest plants also contain a plethora of uninvestigated biodynamic compounds with undiscovered potential for use in modern medicine. Future generations can hope to benefit from these substances only if the species containing them are preserved and studied. Of the hundreds of thousands of plant species inhabiting the rainforests, only a small fraction have been identified and studied, and the potentially beneficial pharmacological properties of many of these are yet to be ascertained.

By the twenty-first century, the US National Cancer Institute identified thousands of plants that have anticancer properties, of which the majority are found in the rainforest. As much as 25 percent of the active ingredients in cancer-fighting drugs come from organisms found only in the Amazon. The rainforest and its immense undiscovered hold the key to unlocking tomorrow’s cures for devastating diseases. Almost 90 percent of people in developing countries still rely on traditional medicine, based largely on different species of plants and animals, for their primary health care. In the Western world, 25 percent of modern medicines contain active ingredients that are extracted or derived from plants. Still more drugs are derived from animals and microorganisms. In the thousands of species of rainforest plants that have not been analyzed are many thousands of unknown plant chemicals that may well be useful in the continuing struggle against constantly evolving pathogens becoming resistant to mainstream drugs. If a cure for cancer or AIDS is found, it will probably originate in the rainforest.

Destruction of the South American Rainforest

Once covering about 14 percent of Earth’s land surface, rainforests have been reduced to only 6 percent because of human activities. If this rate of extinction continues unabated, the last remaining rainforests could be gone by the middle of the twenty-first century. Every day, scores of plant, animal, and insect species become extinct; as these species disappear, possible cures for life-threatening diseases also vanish.

According to the Rainforest Foundation US, about one acre (0.4 hectare) of rainforest disappears every second, in large part because shortsighted governments and landowners believe only harvested timber or land cleared for ranching and farming has value. Another important contributor to the destruction of the Amazon rainforest is the production and transportation of oil. The fragile rainforest environment is easily contaminated by leaks, spills, and the ejection of effluents during pumping operations. Of even greater environmental impact is the destruction resulting from the oil companies’ practice of building roads from inhabited areas to well sites. Pipelines are built along the roads to carry the oil out of the rainforest, but unemployed urban residents often follow the roads into the forest and become squatters on adjoining land. They clear a small section of rainforest, using the slash-and-burn method, to eke out a living as subsistence farmers. However, the land cannot sustain crops for long; when the rainforest is gone, so are most of the nutrients needed for agriculture. The farmers then must move on and destroy more of the forest, regardless of the effects on it or its native species. The tens of thousands of squatters engaging in this destructive practice contribute to the rapid rate of rainforest destruction.

Although aware of the problem, the governments of most South American oil-exporting countries have a strong incentive for underplaying or ignoring the negative impact of oil production in their rainforests; their economies depend on oil, which is one of the continent's largest exports. Ultimately, the demand for oil, driven by high rates in industrialized nations, particularly the United States, was one of the factors causing rainforest destruction.

Too often, environmentally unsustainable practices are subsidized as a means of reducing national debt. In the tropics, governments own or control nearly 80 percent of the rainforest, leaving it vulnerable to administrative policy. In addition to offering tax incentives and credit subsidies that guarantee large profits to private investors who convert forests to pastures and farms, governments allow private concessionaires to log the national forests on terms inherently destructive to the environment. This made beef production the number one source of rainforest deforestation in the 2020s, followed closely by other livestock and soybean production. In addition, massive public expenditures on highways, dams, plantations, and farms, financed by multilateral development lending, destroy, or convert large areas of forest for projects of questionable economic worth.

Solutions

The rainforest is being destroyed for short-term economic gain. Therefore, a viable solution must offer economic incentives to governments and companies. If landowners, governments, and those dwelling in the rainforest were offered practical economic reasons for not razing the rainforest, it could be saved. It has been demonstrated that if medicinal plants, fruits, nuts, rubber, and chocolate are harvested sustainably, the land has greater economic value and will provide more long-term profits in the future. Rainforest land converted to cattle operations yields the landowner only a fraction per hectare of the dollars gained from logging the timber on that land. However, when sustainable resources are harvested, the land yields much more—and this annual income can continue indefinitely if sustainable practices are implemented. The true value of the rainforest is in sustainable resources, not the trees or grazing land. To harvest this wealth effectively, local people and indigenous tribes must be included, providing employment as well as an economic incentive for these people to protect and preserve the forests for future generations.

To save the rainforest, it is necessary that its inhabitants see that there is a consumer demand for sustainable rainforest products, markets that provide the economic incentive to protect their resources for long-term profits rather than short-term gain. When timber is harvested for short-term profits, the medicinal plants and other important sustainable resources that thrive in this delicate are destroyed.

Creating a new source of income by harvesting medicinal plants and other sustainable resources renders rainforests more valuable than when cut and burned and provides an improved standard of living for the local population. This solution can have a real and lasting impact; if every person in the industrialized world were to purchase only renewable and sustainable rainforest products and demand that the resources be harvested by local peoples, consumer demand alone would help ensure preservation.

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