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May 8, 2023

7 min. read

How does deforestation affect the environment and animals?

Forests play an important role in maintaining a healthy global environment. They influence the weather and even the acidity of the oceans, affecting ecosystems thousands of miles beyond their borders. Unfortunately, forests are being destroyed by human activity as they are cleared to make way for grazing animals and their feed, as well as for other agricultural and industrial purposes.

What is deforestation?

The destruction of forests can be broken down into two parts: deforestation and forest degradation.

Deforestation takes place when forested areas are converted to nonforest uses, such as urban sprawl, agriculture, or roads.

Degradation consists of the partial destruction of forests through reducing the number of trees and other flora, which prevents these plants from contributing to ecosystems, societies, and economies as they would when allowed to thrive.

Forests are important to water supplies, climate change mitigation, and sustainable food production, and forests support many of the poorest people globally. The FAO estimates that forests supply 86 million green jobs and that 90 percent of people in extreme poverty rely at least in part on forests for their livelihoods—which are put at risk by deforestation and forest degradation.

On top of deforestation’s economic impact, it also severely impacts the climate—annually, deforestation contributes 1.5 gigatons of carbon, roughly the same amount as Russia.

What are the causes of deforestation?

Deforestation and forest degradation have a wide array of causes, most of which can be directly linked to human activities.

Animal agriculture

Animal agriculture is one of the primary drivers of deforestation. Two of the major contributors within animal agriculture are deforestation to clear land for use as pasture and to grow feed for the billions of animals kept on factory farms around the world.

Livestock ranching

Livestock ranching is a major contributor to deforestation, especially in Latin America. Of deforested land in the Amazon, 70 percent is now occupied by pasture for farmed animals. Not only do farmers clear trees to create open land for this grazing activity, this clearance then damages the soil quality and leads to severe degradation of the land via erosion, compaction, and overgrazing, creating the need to clear even more land for agriculture.

Growing feed

An increased global demand for animal feed has led to countries such as Brazil to clear large swathes of forest to grow crops used to feed farmed animals. Soy is a particularly common crop. Between 1994 and 2004, the land area used to grow soy in Latin America more than doubled, and the amount of land dedicated to soy production remains high today. More than three-quarters (77 percent) of the world’s soy is fed to farmed animals.


The degradation or partial destruction of forests can often be a precursor to the eventual complete clearing of forests. This is especially true for those forested areas where humans are engaged in extractive industry, such as timber logging.

Forest fires

Already fragmented forests and forest edges are the areas most prone to forest fires, especially those fires that originate from human activities such as camping. Many fires in areas such as the Amazon are set deliberately by those aiming to clear the forest, while in the U.S. 89 percent of forest fires also originate from human activity.

Illegal logging

Illegal logging is big business, with an estimated total value of between $51 and $152 billion yearly. On top of the ecological destruction caused by unsustainable and unchecked logging activity, those taking part in these activities are stealing the ecosystems and value that the harvested forests supply to local communities and the nonhuman species that depend on forests.


Mining activity in forested areas is driven by an increasing demand for precious metals and stones. One recent analysis found that four countries—Indonesia, Brazil, Ghana, and Suriname—are disproportionately impacted by deforestation directly related to mining activities. In addition to the loss of forests caused directly by mining, forests are also being lost indirectly in two-thirds of the countries included in the analysis.1

Palm oil

In just under 50 years, global palm oil production has increased from two million tons in 1970 to 71 million tons in 2018. This massive increase in production has been felt most in the small band of land along the equator with the best climate for palm plantation growth. In Indonesia, for example, palm oil production accounted for 23 percent of deforestation from 2001 to 2016, a trend that peaked in 2009.


Demand for toilet paper has been slowly rising over the last several decades. The increased demand for toilet paper has led to an increased pressure on forests. Producing just one ton of toilet paper requires 1.75 tons of raw fiber.


The process of urbanization, wherein people move into new areas and development takes place, directly impacts forested areas through destruction and fragmentation. Urbanization further changes nutrient cycling, introduces nonnative species, and significantly impacts the health of forested areas.

How does deforestation affect animals?

Climate change

The Amazon rainforest is frequently regarded as the lungs of the planet for the role it plays in managing greenhouse gases and releasing oxygen.

As it continues to be destroyed by deforestation, however, these contributions are not the only thing that is being lost. The rainforest also plays a major role in managing precipitation and temperatures locally and across South America. Deforestation could see the Amazon reach a tipping point at which the forest begins to recede without human intervention due to the impact on local climate. This might cause more fires and erosion in the Amazon, and the further loss of forest would accelerate climate change and be detrimental to the whole planet. Humans are not the only animals that will suffer should temperatures in the Amazon and around the world continue to rise and rain patterns shift.

Natural disasters

Deforestation has been noted as responsible for a number of natural disasters, not least the flash floods and landslides that took place in Indonesia in 2019. These disasters left almost 90 people dead and 150 injured. Though the human death toll from these disasters is known, the animals and habitats that were lost as part of these floods and landslides are unknown.

Human interactions

The destruction of forests means that wild animals’ homes and habitats are being displaced and destroyed, bringing wild animals into closer contact with people. These conflicts between humans and animals can take place anywhere. They could be as simple as a bear digging through a trashcan or as dramatic as an elephant ransacking a village.


When wild animals lose their habitats due to deforestation, they are often unable to adapt to the new physical environment and as a result can starve to death.

Acidic oceans

Increased ocean acidity is caused when the water absorbs carbon dioxide from the atmosphere. Because deforestation contributes 10 percent of that carbon dioxide, the continued destruction of forests drives the increasing acidity of the water. As the water absorbs more carbon dioxide it becomes more difficult for a variety of marine creatures.

Loss of habitat

When forests are destroyed the trees are not the only living things killed—the habitats of thousands of different species are also extinguished, causing animals to die. Between 1998 and 2015, an estimated 87 million animals were killed in New South Wales due to the clearing of trees.

How does deforestation affect the environment?

We depend upon forests to store greenhouse gases and help maintain a healthy ecosystem and atmosphere. The destruction of forests has lasting impacts that are often difficult—or even impossible—to reverse.

Climate change

Forests around the world absorb and store a massive 15.6 billion metric tons of carbon dioxide every year. Through deforestation some of this carbon dioxide, over 8 billion tons, is released into the atmosphere, contributing to climate change.

Destruction of homelands

The rate of deforestation on land that is controlled by indigenous communities is markedly lower than on land that is not. When deforestation occurs, indigenous communities can lose their homes or culturally significant natural resources. For these reasons—as well as ongoing cultural commitments to living in balance with nature—many indigenous communities tend to have strong motivations to seek to protect the forests instead of felling them, or allowing others to fell them.

Increased greenhouse gases

Forests store a massive amount of carbon dioxide that is released into the atmosphere when they are destroyed. In 2021, the Amazon rainforest released more CO2 than it absorbed for the first time.

Soil erosion and flooding

Forests help to anchor soil and keep it in place during heavy rainfall. When forests are cut down, their root systems are also removed, making once-forested areas more vulnerable to flooding and erosion.

Water in the atmosphere

The trees that make up forests play a vital role in the water cycle, acting as a mechanism for evaporation. The water that is pulled from trees forms clouds that release rain hundreds or even thousands of miles away from the source forest. The destruction of forests disrupts this cycle and can have deadly impacts on environments around the world.

How does deforestation affect humans?

Food insecurity

Deforestation has a profound negative impact on the amount of precipitation experienced around the world. This reduction in rainfall in turn reduces our ability to grow food that relies on a healthy and operational water system.


The continued destruction of forests also increases the likelihood of pandemics in humans, as interactions between people and animals increase. Research also suggests that the animals that thrive in areas converted from forest to urban uses are in many cases those most likely to carry disease which can mutate and make the jump into humans.

Local people and their livelihoods

Local communities, especially of indigenous people, are the most at risk when it comes to deforestation, as they often rely on forests for much of their livelihood.


Forests play a vital role in maintaining the health of humans, other animals, and the environment. Unfortunately, they are being destroyed by human activity on a vast scale. Some of the best steps we can take as individuals to manage the destruction caused by our consumption are to reduce or eliminate meat eating, reduce consumption of goods such as paper, and to limit consuming products containing palm oil.



Stefan Giljum et al., “A Pantropical Assessment of Deforestation Caused by Industrial Mining,” PNAS 119, no. 38 (2022),