The Causes and Effects of Deforestation, Explained

Deforestation is the process of clearing forests and using the land for other purposes. Although it’s been a part of human society for thousands of years, the pace of deforestation has exploded in recent years, and the planet is paying the price. The causes and effects of deforestation are complex and intertwined, and the impacts are far-reaching and undeniable. Let’s take a closer look at how deforestation works, and how it negatively impacts the planet, animals and humanity.

What Is Deforestation?

Deforestation is the permanent clearing and repurposing of previously forested land. Though there are a number of motivations behind deforestation, it’s generally carried out to repurpose the land for other uses, mainly agriculture, or to extract resources.

Deforestation itself is nothing new, as humans have been clearing forested land for millennia. But the rate at which we destroy forests has increased dramatically: half of all deforestation that’s occurred since 8,000 BC took place in the last 100 years.

In addition to deforestation, forested land is also lost through a similar process known as forest degradation. This is when some, but not all, of the trees in a forested area are cleared, and the land is not repurposed for any other use.

While forest degradation isn’t a good thing by any measure, it’s much less harmful in the long-term than deforestation. Degraded forests will grow back over time, but the trees lost to deforestation are usually lost forever.

How Much Land Has Already Been Deforested?

When the last Ice Age ended around 10,000 years ago, there were roughly six billion hectares of forest on Earth. Since then, around a third of that forest, or two billion hectares, has been destroyed. Around 75 percent of this loss occurred over the last 300 years.

The United Nations Food and Agriculture Organization (FAO) estimates that currently, humans destroy around 10 million hectares of forest every year.

Where Does Deforestation Occur?

Although it happens around the world to some degree, around 95 percent of deforestation occurs in the tropics, and one-third of that takes place in Brazil. Another 14 percent occurs in Indonesia; collectively, Brazil and Indonesia account for about 45 percent of all deforestation worldwide. About 20 percent of tropical deforestation takes place in South American countries other than Brazil, and another 17 percent occurs in Africa.

By contrast, around two-thirds of all forest degradation occurs in temperate regions, primarily North America, China, Russia and South Asia.

What Are the Biggest Drivers of Deforestation?

Humans deforest land for a number of reasons, but the biggest by far is agriculture. According to the United Nations, 90 percent of global deforestation is carried out to repurpose the land for agricultural use — mostly to raise cattle, grow soybeans and produce palm oil.

Beef Production

Beef production is the single-biggest driver of deforestation, tropical and otherwise. Around 39 percent of global deforestation, and 72 percent of deforestation in Brazil alone, is carried out to create grazing pastures for cattle.

Soy Production (Mostly to Feed Livestock)

Another significant driver of agricultural deforestation is soybean production. While soy is a popular meat and dairy replacement, only around seven percent of global soy is directly consumed by humans. The majority of soy — 75 percent — is used to feed livestock, meaning that most soy-driven deforestation is carried out to aid in agricultural expansion.

Palm Oil Production

The conversion of forested land to palm oil plantations is another primary motivation behind tropical deforestation. Palm oil is a versatile ingredient that’s used in a wide variety of everyday products, including nuts, bread, margarine, cosmetics, fuel and more. It’s derived from the fruit of oil palm trees, and is grown mostly in Indonesia and Malaysia.

Paper and Other Agriculture

Beef, soy and palm oil are collectively responsible for 60 percent of tropical deforestation. Other notable drivers include forestry and the production of paper (13 percent of tropical deforestation), rice and other cereals (10 percent), and vegetables, fruits and nuts (seven percent).

What Are the Environmental Impacts of Deforestation?

Deforestation impacts the environment in a number of negative ways, some more obvious than others.

Global Warming and Greenhouse Gas Emissions

Deforestation emits massive amounts of greenhouse gasses, and is a significant contributor to rising global temperatures, in a few different ways.

Trees trap carbon dioxide from the atmosphere and store it in their trunks, branches, leaves and roots. This makes them a crucial tool for reducing global warming, as carbon dioxide is a potent greenhouse gas. When those trees are removed, however, that carbon dioxide is then released back into the air.

The greenhouse emissions don’t end there, however. As we’ve seen, the vast majority of deforested land is converted for agricultural use, and agriculture itself is a huge contributor to global warming as well. Animal agriculture is especially damaging, with scientists estimating that between 11 and 20 percent of all greenhouse gas emissions come from livestock farms.

Finally, the absence of trees on deforested land means that carbon dioxide that’s emitted from other sources, such as vehicles or local communities, is no longer being stored by trees. As such, deforestation increases net greenhouse emissions in three ways: it releases the carbon that’s already stored in the forest, it prevents the trapping of additional carbon from other sources and it facilitates the release of “new” greenhouse gasses through its conversion to agricultural land.

Loss of Biodiversity

Earth is a vast, interconnected ecosystem, and a certain level of biodiversity is required to ensure that it maintains its equilibrium. Deforestation is reducing this biodiversity every day.

Forests are teeming with life. Millions of different animals, plants and insects call the forest their home, including three million different species in the Amazon rainforest alone. Over a dozen animal species can only be found in the Amazon rainforest.

Destroying these forests destroys these animals’ homes and, in the long term, threatens the continued survival of their species. This isn’t a hypothetical concern: every day, about 135 plant and animal species go extinct because of deforestation, and an estimated 10,000 additional species — including 2,800 species of animal — are at risk of extinction due to deforestation in the Amazon alone. Palm oil production in particular has driven orangutans to the brink of extinction.

We are living in a period mass extinction — the sixth to occur during Earth’s lifetime. This matters not only because it’s sad when cute animals die, but rather, because accelerated periods of extinction threaten to disrupt the delicate equilibrium that allows Earth’s ecosystem to continue existing.

A 2023 study found that over the last 500 years, entire genuses have been going extinct at a rate 35 times higher than the historical average. This rate of extinction, the authors of the study wrote, is “destroying the conditions that make human life possible.”

Soil Erosion and Degradation

It may not get as much attention as oil or gold, but soil is a vital natural resource that we and countless other creatures rely on to survive. Trees and other natural vegetation shield soil from the sun and rain, and help hold it in place. When those trees are removed, the nutrient-rich topsoil becomes loosened, and is more susceptible to erosion and degradation by the elements.

Soil erosion and soil degradation have a number of dangerous effects. In the most general sense, degradation and erosion make soil less viable for supporting plant life, and reduces the number of plants that the land can support. Degraded soil is also worse at retaining water, thus increasing the risk of flooding. Sediment from eroded soil is also a major water pollutant that imperils fish populations and human drinking water alike.

These effects can continue for decades after deforested land is repurposed, as the crops grown on deforested land often don’t hold onto the topsoil as firmly as the natural vegetation did.

What Can Be Done to Reduce Deforestation?

Government Regulation

In Brazil, President Luiz Inacio Lula da Silva has reduced deforestation rates in his country significantly since taking office in 2019. His administration has accomplished this largely by empowering regulatory agencies to more closely track and monitor illegal deforestation, increasing enforcement of anti-deforestation laws, and in general, cracking down on illegal deforestation.

Industry Pledges

There’s also some sign that voluntary industry pledges can help curb deforestation. In 2006, a collective of major soybean traders agreed to no longer buy soy that was grown on deforested land. Eight years later, the share of soybean expansion on previously-forested lands fell from 30 percent to one percent.

Reforestation and Afforestation

Lastly, there is reforestation and afforestation — the process of planting trees on deforested land or new land, respectively. In China, afforestation initiatives enacted by the government in the late 1970s have increased the country’s tree cover from 12 percent to 22 percent, while local reforestation programs have planted at least 50 million additional trees around the Earth in the last 35 years.

The Bottom Line

Deforestation’s environmental impact is clear: it releases greenhouse gasses, pollutes the water, kills plants and animals, erodes the soil and reduces the planet’s biodiversity. Unfortunately, it’s also become more and more common over the centuries, and without focused, aggressive action to curb it, deforestation will likely only get worse over time.