Forests cover 31% of the land area on our planet. They help people thrive and survive by, for example, purifying water and air. Many animals also rely on forests. Eighty percent of the world’s land-based species, such as elephants and rhinos, live in forests. Forests also play a critical role in mitigating climate change because they act as a carbon sink—soaking up carbon dioxide that would otherwise be free in the atmosphere and contribute to ongoing changes in climate patterns.
Deforestation is a particular concern in tropical rain forests because these forests are home to much of the world’s biodiversity. For example, in the Amazon around 17% of the forest has been lost in the last 50 years, mostly due to forest conversion for cattle ranching. Deforestation in this region is particularly rampant near more populated areas, roads and rivers, but even remote areas have been encroached upon when valuable mahogany, gold, and oil are discovered.
Deforestation can happen quickly, such as when a fire sweeps through the landscape or the forest is clear-cut to make way for an oil palm plantation. While deforestation appears to be on the decline in some countries, it remains disturbingly high in others—including Brazil and Indonesia—and a grave threat to our world’s most valuable forests still remains.
Over the next 15 years, forest landscapes could be lost to rampant deforestation. If nothing is done, 11 of the world’s most ecologically important forest landscapes including forest homes or orangutans, tigers, and elephants—will account for over 80 percent of forest loss globally by 2030. Up to 420 million acres of forest could be lost before 2030 in these “deforestation fronts” if current trends continue. The hot spots are located in the Amazon, the Atlantic Forest and Gran Chaco, Borneo, the Cerrado, Choco-Darien, the Congo Basin, East Africa, Eastern Australia, Greater Mekong, New Guinea, and Sumatra.
Causes of Deforestation:
CONVERSION TO AGRICULTURE
Expanding agriculture, due to an increased population and shifts in diet, is responsible for most of the world’s deforestation. As the human population continues to grow, there is an obvious need for more food. In addition, agricultural products, such as soy and palm oil, are used in an ever-increasing list of products, from animal feed to lipstick and biofuels. Rising demand has created incentives to convert forests to farmland and ranch land. Once a forest is lost to agriculture, it is usually gone forever—along with many of the plants and animals that once lived there.
Fires are a natural and beneficial element of many forest landscapes, but they are problematic when they occur in the wrong place, at the wrong frequency or at the wrong severity. Each year, millions of acres of forest around the world are destroyed or degraded by fire. The same amount is lost to logging and agriculture combined. Fire is often used as a way to clear land for other uses such as planting crops. These fires not only alter the structure and composition of forests, but they can open up forests to invasive species, threaten biological diversity, alter water cycles and soil fertility, and destroy the livelihoods of the people who live in and around the forests.
Impacts of Deforestation:
About 80% of the world’s documented land-based species can be found in forests. When species lose their forest homes, they are often unable to subsist in the small fragments of forested land left behind. They become more accessible to hunters and poachers, their numbers begin to dwindle and some eventually go extinct. Even localized deforestation can result in extinctions as many unique species exist in small isolated geographic locations in the world.
INCREASED GREENHOUSE GAS EMISSIONS
Forests are carbon sinks and, therefore, help to mitigate the emission of carbon dioxide and other greenhouse gases. Tropical forests alone hold more than 228 to 247 gigatons of carbon, which is more than seven times the amount emitted each year by human activities. But when forests are cut, burned or otherwise removed they emit carbon instead of absorb carbon. Deforestation and forest degradation are responsible for around 15% of all greenhouse gas emissions. These greenhouse gas emissions contribute to rising temperatures, changes in patterns of weather and water, and an increased frequency of extreme weather events. For example, in Sumatra, rain forests on deep peat lands are being cleared, drained and converted to pulp plantations, contributing to Indonesia’s high greenhouse gas emissions. Changes in climate can affect forest-dwelling creatures by altering their habitats and decreasing availability of food and water. Some will be able to adapt by moving to higher elevations or latitudes, but species losses may occur.
DISRUPTION OF WATER CYCLES
Trees play a key role in the local water cycle by helping to keep a balance between the water on land and water in the atmosphere. But when deforestation or degradation occurs, that balance can be thrown off, resulting in changes in precipitation and river flow.
INCREASED SOIL EROSION
Without trees to anchor fertile soil, erosion can occur and sweep the land into rivers. The agricultural plants that often replace the trees cannot hold onto the soil. Many of these plants—such as coffee, cotton, palm oil, soybean and wheat—can actually exacerbate soil erosion. Scientists have estimated that a third of the world’s arable land has been lost through soil erosion and other types of degradation since 1960. And as fertile soil washes away, agricultural producers move on, clearing more forest and continuing the cycle of soil loss.