What Are the Causes and Effects of Deforestation?

Forests are a critical global resource, covering around 30 percent of the planet or 4.06 billion hectares. Increasing rates of deforestation threaten this important resource but also much more — as forests are deeply intertwined with the impacts of climate change, biodiversity and the livelihoods of people who depend on these precious and powerful ecosystems.

What Is Deforestation?

Deforestation is the practice of intentionally cutting down trees to clear land for other uses. In the past 10,000 years, the world has lost 2 billion hectares — or one-third — of its forested land, and half of that has occurred since 1900. The UN Food and Agriculture Organization (FAO) estimates that an average of 10 million hectares of forest are cut down each year, but some years are much worse than others. 2016 remains the worst year on record for deforestation at 29.7 million hectares, partly due to significant forest fires.

What Are the Effects of Deforestation?

The impacts of deforestation are felt throughout the environment and the natural cycles that regulate life on Earth, as well as in human communities and the animals that depend on forests for habitat.

What Are the Negative Effects of Deforestation on the Environment?

Soil Erosion and Desertification

Trees and natural vegetation help to hold soil in place. When they are removed, the nutrient-rich topsoil erodes, and is easily washed away in heavy rains or blown away by wind. Rough, sandy particles that can’t retain water are left behind, making the land unsuitable for growing crops as it eventually turns into a desert. As forests also regulate the water cycle, clearing them leads to drier local climates, further adding to the risk of desertification.

Climate Change

Forests store huge amounts of carbon, which can be released into the atmosphere when they are cut down. Deforestation accounts for around 10 percent of anthropogenic carbon emissions. Tropical forests are under such severe assault that they have tipped from being a net sink to a net source for carbon emissions, now emitting more than they can store.

Floods

A landmark study published in Global Change Biology in 2007 found evidence from around the globe that deforestation increases the frequency of flooding events as well as making the impacts more severe — increasing the length of floods, the number of people displaced and killed and the physical damage caused. Various further studies have also revealed the different ways that deforestation increases floods. For example, a 2012 study published in Water Resources Research on deforestation in Canada found that felling large areas of forest in snowy regions can double or even quadruple the number of large floods around the streams and rivers that pass through those forests by exposing snow to sunlight and making it melt faster. A 2022 study published by PNAS found that coastal cities in West Africa are experiencing more frequent thunderstorms and flash flooding due to deforestation, which alters the local climate.

How Does Deforestation Affect Us?

Health

Deforestation negatively impacts public health in several ways. Fragmentation of wildlife habitat through forest clearing has increased the spillover of novel pathogens from wildlife to people. According to the World Wildlife Fund, the loss of forest also risks the loss of potential future medicinal resources. By contributing to and exacerbating the impacts of climate change, such as floods, deforestation increases the risk of death, particularly for people in parts of the world that are more vulnerable to extreme weather. When we lose forests, we also lose a source of more direct health benefits such as improved mental and physical well-being and cleaner air.

Food Insecurity

Forests provide food for millions of people and fuelwood for cooking for 2.4 billion, particularly in developing countries. By maintaining soil quality, regulating climate and providing habitats and food for a diverse range of species, forests are a critical component of food production beyond their bounds as well. All of these benefits are threatened by deforestation, which also adds to the pressure on global food supplies due to climate change.

Local People and Their Livelihoods

Communities who live in and near forests are deeply impacted by deforestation. According to the World Bank, rural households living near forests can derive as much as 22 percent of their income from forest resources including timber, food, fuel, fodder, construction materials and medicine. As these resources become more scarce due to tree clearing, communities from Cameroon to India are struggling to make ends meet. Deforestation can also lead to migration, social disruption and conflict.

Effects of Deforestation on Biodiversity

Habitat Loss

Forests are some of the most diverse ecosystems on Earth, providing homes to trees, plants, animals, insects, microorganisms and carbon-sequestering fungi. Deforestation fragments and degrades this habitat, reducing or destroying its capacity to support other species.

Wildlife Extinction

When their habitat is destroyed, many forest-dwelling species struggle to survive in the pockets of forest that are left. Smaller areas of habitat can only support smaller populations of a species, reducing their gene pool and leaving them more vulnerable to hunting, poaching and predators. As some species are unique to specific forest regions, they can easily become extinct when their habitat is destroyed.

Acidic Oceans

When carbon dioxide in the atmosphere dissolves into the oceans, it lowers the pH of the water and causes acidification. Because forests are such important carbon sinks, another result  of deforestation is that more carbon dioxide ends up in the oceans as less is absorbed by trees.

What Animals Are Affected By Deforestation?

Deforestation and unsustainable logging threaten more than 4,000 species. Forest-dependent animals that have gone extinct just this century include the Formosan clouded leopard of Taiwan, the cryptic treehunter bird of Brazil and the Mount Glorious torrent frog of Australia.

What Are the Causes of Deforestation?

Animal Agriculture

Animal agriculture is the leading cause of deforestation. A massive 41 percent of tropical deforestation — 2.1 million hectares a year — is directly linked to the expansion of pasture for grazing beef cattle, mostly in Brazil. In addition, nearly 500,000 hectares of forest is cleared every year to grow soy, the majority of which — around 77 percent — ends up as livestock feed.

Forest Fires

Fires are a naturally occurring event in some forest ecosystems and controlled fires have also been used sustainably by Indigenous communities for centuries to clear small pockets of land for agriculture. But forest fires are becoming more frequent and ferocious, breaking out in new regions as humid forests dry out. The remaining fragmented forests are more prone to fires as climate change is making conditions drier and hotter, which in turn makes it easier for fires to start and grow out of control.

In 2021, Russia had its worst fire season on record (monitoring began properly in 2001), with 18.13 million hectares of forest destroyed. The Amazon rainforest had a particularly bad year of fires in 2019, with over 9,000 fires raging at one point. Last month, 17,000 hectares of pine forest burned to the ground in France.

Illegal Logging

There is a multi-billion dollar industry based on illegally harvested timber and related products such as paper and packaging. Some illegal logging also occurs to replace natural forest with monoculture plantations. 

Mining

Around 44 percent of large-scale mining operations are located in forests, and experts have warned that granting new mining licenses in currently protected areas of the Amazon, as Brazil’s president wants to do, will result in thousands of square kilometers of new deforestation. Illegal mining, mainly for gold, drove the destruction of more than 40,000 hectares of forest in Tambopata National Reserve in Peru from 2001 to 2014.

Overpopulation

The human population already stands on the cusp of 8 billion and is projected to peak at 10.88 billion at the turn of the next century. If current unsustainable uses of land continue apace, including clearing forests for agriculture and exploitation of other resources, the growth in population will exert further pressure on forest ecosystems.

Palm Oil

Around 66 million tons of palm oil is produced every year for use in household products, food, animal feed and as fuel for power and vehicles. The amount of land used to grow oil palm has grown from 4 million hectares in 1980 to 19 million in 2018. Along with soy, the expansion of oil palm plantations is the second biggest cause of deforestation globally after animal agriculture — though it accounts for less than half the amount of deforestation caused by cattle ranching. Nonetheless, it has been a disaster for forest wildlife, threatening nearly 200 species on the IUCN’s red list, including tigers and orangutans.

Paper

Around 405 million tonnes of paper and paperboard are produced annually, accounting for roughly 13 to 15 percent of total wood consumption — and demand for these products is increasing. Forests are being cleared in biodiversity hotspots to grow pulp plantations. Several forest regions, including the old-growth boreal forests of Canada, are also being clear-cut to produce pulp for making toilet paper and other tissue products.

Urbanization

It was once hoped that urbanization, the process by which a population moves to urban areas, would decrease pressure on forests by slowing down the clearing of land for agriculture. But instead, the key drivers of deforestation have shifted too, with more populous urban areas driving up demand for products like beef, as found in a study published in 2010 in Nature Geoscience and a more recent study published in Environmental Science and Pollution Research International in 2020.

Where Is Deforestation Happening?

Deforestation in South America

Brazil has by far the worst rate of deforestation in the world, with a net loss of 1.45 million hectares of forest per year. But all of South America, bar a handful of countries including Chile and Costa Rica, are losing more forest than they are gaining. Around 17 percent of the Amazon, the majority of which is in Brazil, had been cleared by 2018 — the same year Jair Bolsanaro was elected President, since when he has been loosening environmental protections for the rainforest and encouraging its development. The second largest forest in South America is the Cerrado, which covers more than 20 percent of Brazil but is often overlooked. It has suffered twice as much deforestation as the Amazon since 2008, mainly due to the expansion of animal agriculture.

Deforestation in Southeast Asia

Indonesia is another deforestation hotspot, with rates comparable to South America. Palm oil and logging are the main causes of deforestation in Indonesia as well as Malaysia. More than half of the natural forest cover of Southeast Asia has been lost — a catastrophe for the region’s wildlife.

Deforestation in Africa

Deforestation rates vary greatly between African countries. Agricultural expansion is a major driver, with cocoa playing a significant role, particularly in Côte d’Ivoire, Ghana, Nigeria, and Cameroon. Producing nearly 3 million tons of cocoa every year requires huge amounts of land. Protected areas and their wildlife have been ravaged by cocoa production in Côte d’Ivoire, and 10 percent of Ghana’s forests were cleared for cocoa production between 2001 and 2014. Logging for timber and demand for charcoal as a cooking fuel are also big drivers of deforestation in different parts of the continent.

How Can We Stop Deforestation?

Consuming Less and More Consciously

There are several actions people can take as individuals to prevent further deforestation, including buying less and making more conscious choices about what to buy. For example, you could look for second hand wood products like furniture and recycled tissue and paper products, or reduce consumption of products containing palm oil.

Eating Less Meat

As animal agriculture is the biggest driver of deforestation, cutting down on or avoiding meat is another key action individuals can take. Even if the meat itself has not been imported from a country experiencing deforestation, feed for farmed animals including dairy cows, pigs and chickens is often sourced from deforested areas. A 2021 study published in Nature found that replacing half of global meat consumption with fungi-derived protein could prevent 82 percent of future deforestation.

Government Regulations

Governments must do more to end deforestation. At the 2021 UN Climate Summit, COP26, more than 100 world leaders committed to halt and reverse deforestation and land degradation by 2030, offering up billions in funding to that end. But a similar pledge in 2014, the New York Declaration on Forests, was a failure. 

Still, because corporate deforestation commitments are insufficient on their own, government regulations remain essential. For example, the European Union, as the second biggest importer of agricultural products resulting from deforestation, has proposed mandatory due diligence requirements on companies to improve reporting and transparency in their supply chains. Both producer and consumer countries of products linked to deforestation need to improve forest governance such as better auditing, licensing and certification programs. 

Spread Awareness About Deforestation

Research show the simple act of talking about climate change is one of the most effective forms of climate action. This could include discussing the larger role forests play in planetary health or highlighting products that are most likely to have come from deforested areas.

Leave Fossil Fuels and Palm Oil Behind

Burning fossil fuels is the biggest contributor to greenhouse gas emissions, generating more than forests can absorb. As long as humanity keeps burning fossil fuels, climate change will keep negatively impacting forests and contribute to forest loss through worsening wildfires. But what we replace fossil fuels with matters to deforestation too. Palm oil is already being used as a replacement, but its environmental and climate costs are significant. Reducing the need for fossil and biofuels through, for example, improved transportation infrastructure, and replacing the remainder with cleaner sources of energy and fuel is crucial.

Reforestation and Afforestation

Reforestation involves the restoration of an area that was recently deforested, while afforestation means establishing forests where there were none or have been none for a long time. Allowing forests to naturally regenerate is gaining recognition as a cost-effective reforestation strategy. Reforestation is occurring in countries from Russia to China — but the key challenge is whether these efforts can outpace the rate at which trees are lost. There are notable afforestation efforts underway around the world, including China, which has increased its forest cover by 22 percent since the late 1970s.

Further Action

In addition to reducing your own consumption of deforestation-linked products, you can support or campaign for policies that aim to reduce such consumption at a larger scale. Another key form of action — support Indigenous communities who are defending forests from being cleared by corporations by donating to relevant nonprofits or to legal defense funds for Indigenous activists.