Why are rainforests important?

Rainforest in Malaysian Borneo

Flying over the heart of the Amazon is like flying over an ocean of green: an expanse of trees broken only by rivers. Even more amazing than their size is the role the Amazon and other rainforests around the world play in our everyday lives.

While rainforests may seem like a distant concern, these ecosystems are critically important for our well-being.

Rainforests are often called the lungs of the planet for their role in absorbing carbon dioxide, a greenhouse gas, and increasing local humidity. Rainforests also stabilize climate, house incredible amounts of plants and wildlife, and produce nourishing rainfall all around the planet.

Rainforests:

  • help stabilize the world’s climate;
  • provide a home to many plants and animals;
  • maintain the water cycle
  • protect against flood, drought, and erosion;
  • are a source for medicines and foods;
  • support tribal people; and
  • are an interesting place to visit

Rainforests help stabilize climate

Rainforests help stabilize the world’s climate by absorbing carbon dioxide from the atmosphere. Scientists have shown that excess carbon dioxide in the atmosphere from human activities is contributing to climate change. Therefore, living rainforests have an important role in mitigating climate change. But when rainforests are chopped down and burned, the carbon stored in their wood and leaves is released into the atmosphere, contributing to climate change.

Rainforests also affect local weather conditions by creating rainfall and moderating temperatures.

Rainforests and rainfall

Rainforests contribute to rainfall through transpiration, which is the process of water movement through a plant and its release into the air via leaves, stems, and flowers. Plants release water as a byproduct of photosynthesis.

Water released by plants contribute to local humidity or moisture in the air. Because a forest consists of a large number of trees, the volume of water released via transpiration can contribute to the formation of rain clouds, resulting in rainfall. Very large rainforests, like the Amazon, can drive rainfall over very large areas. By one estimate, the Amazon is reponsible for 70% of rainfall in southern Brazil.

Rainforests and local temperature

Tropical forests can have a localized cooling effect by increasing humidity through transpiration and contributing to wind currents. Additionally, shade from the forest canopy can result in dramatically cooler temperatures relative to areas exposed to direct sunlight. In fact, one of the top complaints from local people following deforestation is about the increase in local temperature.

Rainforests provide a home for plants and wildlife

Rainforests are home to a large number of the world’s plant and animals species, including many endangered species. As forests are cut down, many species are doomed to extinction.

Most rainforest species can survive only in their natural habitat. As their habitat is destroyed, many well-known rainforest species are threatened with extinction, including orangutans, rhinos, tigers, gorillas, elephants, as well as many birds, monkeys, reptiles, and amphibians.

Zoos cannot save all animals.

Rainforests help maintain the water cycle

The role of rainforests in the water cycle is to add water to the atmosphere through the process of transpiration (in which plants release water from their leaves during photosynthesis). This moisture contributes to the formation of rain clouds, which release the water back onto the rainforest. In the Amazon, 50-80 percent of moisture remains in the ecosystem’s water cycle.

When forests are cut down, less moisture goes into the atmosphere and rainfall declines, sometimes leading to drought.

In recent years, the rainforests of Borneo and the Amazon have experienced very severe droughts. These have been made worse by deforestation.

Moisture generated by rainforests travels around the world. Scientists have discovered that rainfall in America’s Midwest is affected by forests in the Congo. Meanwhile, moisture created in the Amazon ends up falling as rain as far away as Texas, and forests in Southeast Asia influence rain patterns in southeastern Europe and China. Distant rainforests are therefore important to farmers everywhere.

Rainforests reduce erosion

The roots of rainforest trees and vegetation help anchor the soil. When trees are cut down there is no longer anything to protect the ground, and soils are quickly washed away with rain. The process of washing away of soil is known as erosion.

As soil is washed down into rivers it causes problems for fish and people. Fish suffer because water becomes clouded and spawning grounds fill with silt, while people have trouble navigating waterways that are shallower because of the increased amount of dirt in the water. Meanwhile, farmers lose topsoil that is needed for growing crops, and dams generate less electricity as water is lost to runoff.

On steep hillsides, loss of forest can trigger landslides. For example, thousands of people were killed in Central America during Hurricane Mitch of 1998 when deforested hillsides collapsed. Had forests been maintained, the death toll would have been lower.

Forests also play an important role in reducing damage from flooding by reducing the rate of water runoff.

During the devastating 2004 Indian Ocean tsunami, areas where mangrove forests had been cut down suffered more devastation than areas where healthy mangrove forests remained as a buffer. Mangroves also help protect against coastal erosion.

Rainforests provide resources for people

People have long used forests as a source of food, wood, medicine, and recreation. When forests are lost, they can no longer provide these resources. Instead people must find other places to get these materials and services. They also must find ways to pay for the things they once got for free from the forest.

As a frequent visitor to rainforests, I can attest that these ecsosystems provide much more than life-saving medicines and nourishing fruit. Rainforests are found in a variety of landscapes: some are situated on scenic mountain ranges, others hug giant lowland rivers, while more still are found near beautiful beaches and coral reefs. Rainforests offer opportunities for cultural exchange, photography, adventure, fishing, hiking, relaxation, birding and wildlife spotting.

Chapter review questions

  • What are some reasons why rainforests are important?
  • How do rainforests affect the climate?
  • How do rainforests affect rainfall?
  • How do rainforests affect local temperatures?
  • What is one reason why the Amazon rainforest is important?
  • Why is deforestation a threat to animals?
  • What are some examples of endangered rainforest animals?
  • How do rainforests contribute to weather patterns?
  • How does deforestation affect rainfall?
  • Why are tropical rainforests important for farmers in places like America?
  • How do rainforests help control soil erosion?
  • Why is soil erosion bad?
  • How do forests help protect against storm damage and other disasters?
  • What are some benefits provided by rainforests?

Additional resources