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Deforestation or forest clearance is the removal and destruction of a forest or stand of trees from land that is then converted to non-forest use.[1] Deforestation can involve conversion of forest land to farms, ranches, or urban use. About 31% of Earth's land surface is covered by forests at present.[2] This is one-third less than the forest cover before the expansion of agriculture, with half of that loss occurring in the last century.[3] Between 15 million to 18 million hectares of forest, an area the size of Bangladesh, are destroyed every year. On average 2,400 trees are cut down each minute.[4] Estimates vary widely as to the extent of deforestation in the tropics.[5][6] In 2019, nearly a third of the overall tree cover loss, or 3.8 million hectares, occurred within humid tropical primary forests. These are areas of mature rainforest that are especially important for biodiversity and carbon storage.[7][8]
The direct cause of most deforestation is agriculture by far.[9] More than 80% of deforestation was attributed to agriculture in 2018.[10] Forests are being converted to plantations for coffee, palm oil, rubber and various other popular products.[11] Livestock grazing also drives deforestation. Further drivers are the wood industry (logging), urbanization and mining. The effects of climate change are another cause via the increased risk of wildfires (see deforestation and climate change).
Deforestation results in habitat destruction which in turn leads to biodiversity loss. Deforestation also leads to extinction of animals and plants, changes to the local climate, and displacement of indigenous people who live in forests. Deforested regions often also suffer from other environmental problems such as desertification and soil erosion.
Another problem is that deforestation reduces the uptake of carbon dioxide (carbon sequestration) from the atmosphere. This reduces the potential of forests to assist with climate change mitigation. The role of forests in capturing and storing carbon and mitigating climate change is also important for the agricultural sector.[12] The reason for this linkage is because the effects of climate change on agriculture pose new risks to global food systems.[12]
Since 1990, it is estimated that some 420 million hectares of forest have been lost through conversion to other land uses, although the rate of deforestation has decreased over the past three decades. Between 2015 and 2020, the rate of deforestation was estimated at 10 million hectares per year, down from 16 million hectares per year in the 1990s. The area of primary forest worldwide has decreased by over 80 million hectares since 1990. More than 100 million hectares of forests are adversely affected by forest fires, pests, diseases, invasive species, drought and adverse weather events.[13]
Definition
Deforestation is defined as the conversion of forest to other land uses (regardless of whether it is human-induced).[14]
Deforestation and forest area net change are not the same: the latter is the sum of all forest losses (deforestation) and all forest gains (forest expansion) in a given period. Net change, therefore, can be positive or negative, depending on whether gains exceed losses, or vice versa.[14]
Current status
The FAO estimates that the global forest carbon stock has decreased 0.9%, and tree cover 4.2% between 1990 and 2020.[15]: 16, 52
| Region | 1990 | 2020 |
|---|---|---|
| Europe (including Russia) | 158.7 | 172.4 |
| North America | 136.6 | 140.0 |
| Africa | 94.3 | 80.9 |
| South and Southeast Asia combined | 45.8 | 41.5 |
| Oceania | 33.4 | 33.1 |
| Central America | 5.0 | 4.1 |
| South America | 161.8 | 144.8 |
As of 2019 there is still disagreement about whether the global forest is shrinking or not: "While above-ground biomass carbon stocks are estimated to be declining in the tropics, they are increasing globally due to increasing stocks in temperate and boreal forest.[16]: 385
Deforestation in many countries—both naturally occurring[17] and human-induced—is an ongoing issue.[18] Between 2000 and 2012, 2.3 million square kilometres (890,000 square miles) of forests around the world were cut down.[19] Deforestation and forest degradation continue to take place at alarming rates, which contributes significantly to the ongoing loss of biodiversity.[12]
Deforestation is more extreme in tropical and subtropical forests in emerging economies. More than half of all plant and land animal species in the world live in tropical forests.[21] As a result of deforestation, only 6.2 million square kilometres (2.4 million square miles) remain of the original 16 million square kilometres (6 million square miles) of tropical rainforest that formerly covered the Earth.[19] More than 3.6 million hectares of virgin tropical forest was lost in 2018.[22]
The global annual net loss of trees is estimated to be approximately 10 billion.[23][24] According to the Global Forest Resources Assessment 2020 the global average annual deforested land in the 2015–2020 demi-decade was 10 million hectares and the average annual forest area net loss in the 2000–2010 decade was 4.7 million hectares.[14] The world has lost 178 million ha of forest since 1990, which is an area about the size of Libya.[14]
An analysis of global deforestation patterns in 2021 showed that patterns of trade, production, and consumption drive deforestation rates in complex ways. While the location of deforestation can be mapped, it does not always match where the commodity is consumed. For example, consumption patterns in G7 countries are estimated to cause an average loss of 3.9 trees per person per year. In other words, deforestation can be directly related to imports—for example, coffee.[25][26]
In 2023, the Global Forest Watch reported a 9% decline in tropical primary forest loss compared to the previous year, with significant regional reductions in Brazil and Colombia overshadowed by increases elsewhere, leading to a 3.2% rise in global deforestation. Massive wildfires in Canada, exacerbated by climate change, contributed to a 24% increase in global tree cover loss, highlighting the ongoing threats to forests essential for carbon storage and biodiversity. Despite some progress, the overall trends in forest destruction and climate impacts remain off track.[27]
The IPCC Sixth Assessment Report stated in 2022: “Over 420 million ha of forest were lost to deforestation from 1990 to 2020; more than 90% of that loss took place in tropical areas (high confidence), threatening biodiversity, environmental services, livelihoods of forest communities and resilience to climate shocks (high confidence).”[28]
Rates of deforestation
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Global deforestation[31] sharply accelerated around 1852.[32][33] As of 1947, the planet had 15 to 16 million km2 (5.8 to 6.2 million sq mi) of mature tropical forests,[34] but by 2015, it was estimated that about half of these had been destroyed.[35][21][36] Total land coverage by tropical rainforests decreased from 14% to 6%. Much of this loss happened between 1960 and 1990, when 20% of all tropical rainforests were destroyed. At this rate, extinction of such forests is projected to occur by the mid-21st century.[citation needed]
In the early 2000s, some scientists predicted that unless significant measures (such as seeking out and protecting old growth forests that have not been disturbed)[34] are taken on a worldwide basis, by 2030 there will only be 10% remaining,[32][36] with another 10% in a degraded condition.[32] 80% will have been lost, and with them hundreds of thousands of irreplaceable species.[32]
Estimates vary widely as to the extent of deforestation in the tropics.[5][6] In 2019, the world lost nearly 12 million hectares of tree cover. Nearly a third of that loss, 3.8 million hectares, occurred within humid tropical primary forests, areas of mature rainforest that are especially important for biodiversity and carbon storage. This is equivalent to losing an area of primary forest the size of a football pitch every six seconds.[7][8]
Rates of change
A 2002 analysis of satellite imagery suggested that the rate of deforestation in the humid tropics (approximately 5.8 million hectares per year) was roughly 23% lower than the most commonly quoted rates.[40] A 2005 report by the United Nations Food and Agriculture Organization (FAO) estimated that although the Earth's total forest area continued to decrease at about 13 million hectares per year, the global rate of deforestation had been slowing.[41][42] On the other hand, a 2005 analysis of satellite images reveals that deforestation of the Amazon rainforest is twice as fast as scientists previously estimated.[43][44]
From 2010 to 2015, worldwide forest area decreased by 3.3 million ha per year, according to FAO. During this five-year period, the biggest forest area loss occurred in the tropics, particularly in South America and Africa. Per capita forest area decline was also greatest in the tropics and subtropics but is occurring in every climatic domain (except in the temperate) as populations increase.[45]
An estimated 420 million ha of forest has been lost worldwide through deforestation since 1990, but the rate of forest loss has declined substantially. In the most recent five-year period (2015–2020), the annual rate of deforestation was estimated at 10 million ha, down from 12 million ha in 2010–2015.[14]
Africa had the largest annual rate of net forest loss in 2010–2020, at 3.9 million ha, followed by South America, at 2.6 million ha. The rate of net forest loss has increased in Africa in each of the three decades since 1990. It has declined substantially in South America, however, to about half the rate in 2010–2020 compared with 2000–2010. Asia had the highest net gain of forest area in 2010–2020, followed by Oceania and Europe. Nevertheless, both Europe and Asia recorded substantially lower rates of net gain in 2010–2020 than in 2000–2010. Oceania experienced net losses of forest area in the decades 1990–2000 and 2000–2010.[14]
Some claim that rainforests are being destroyed at an ever-quickening pace.[47] The London-based Rainforest Foundation notes that "the UN figure is based on a definition of forest as being an area with as little as 10% actual tree cover, which would therefore include areas that are actually savanna-like ecosystems and badly damaged forests".[48] Other critics of the FAO data point out that they do not distinguish between forest types,[49] and that they are based largely on reporting from forestry departments of individual countries,[50] which do not take into account unofficial activities like illegal logging.[51] Despite these uncertainties, there is agreement that destruction of rainforests remains a significant environmental problem.
The rate of net forest loss declined from 7.8 million ha per year in the decade 1990–2000 to 5.2 million ha per year in 2000–2010 and 4.7 million ha per year in 2010–2020. The rate of decline of net forest loss slowed in the most recent decade due to a reduction in the rate of forest expansion.[14]
Reforestation and afforestation
In many parts of the world, especially in East Asian countries, reforestation and afforestation are increasing the area of forested lands.[52] The amount of forest has increased in 22 of the world's 50 most forested nations. Asia as a whole gained 1 million hectares of forest between 2000 and 2005. Tropical forest in El Salvador expanded more than 20% between 1992 and 2001. Based on these trends, one study projects that global forestation will increase by 10%—an area the size of India—by 2050.[53] 36% of globally planted forest area is in East Asia – around 950,000 square kilometers. From those 87% are in China.[54]
Status by region
Rates of deforestation vary around the world. Up to 90% of West Africa's coastal rainforests have disappeared since 1900.[55] Madagascar has lost 90% of its eastern rainforests.[56][57] In South Asia, about 88% of the rainforests have been lost.[58]
Mexico, India, the Philippines, Indonesia, Thailand, Burma, Malaysia, Bangladesh, China, Sri Lanka, Laos, Nigeria, the Democratic Republic of the Congo, Liberia, Guinea, Ghana and the Ivory Coast, have lost large areas of their rainforest.[59][60]
Much of what remains of the world's rainforests is in the Amazon basin, where the Amazon Rainforest covers approximately 4 million square kilometres.[61] Some 80% of the deforestation of the Amazon can be attributed to cattle ranching,[62] as Brazil is the largest exporter of beef in the world.[63] The Amazon region has become one of the largest cattle ranching territories in the world.[64] The regions with the highest tropical deforestation rate between 2000 and 2005 were Central America—which lost 1.3% of its forests each year—and tropical Asia.[48] In Central America, two-thirds of lowland tropical forests have been turned into pasture since 1950 and 40% of all the rainforests have been lost in the last 40 years.[65] Brazil has lost 90–95% of its Mata Atlântica forest.[66] Deforestation in Brazil increased by 88% for the month of June 2019, as compared with the previous year.[67] However, Brazil still destroyed 1.3 million hectares in 2019.[7] Brazil is one of several countries that have declared their deforestation a national emergency.[68][69] Paraguay was losing its natural semi-humid forests in the country's western regions at a rate of 15,000 hectares at a randomly studied 2-month period in 2010.[70] In 2009, Paraguay's parliament refused to pass a law that would have stopped cutting of natural forests altogether.[71]
As of 2007, less than 50% of Haiti's forests remained.[72]
From 2015 to 2019, the rate of deforestation in the Democratic Republic of the Congo doubled.[73] In 2021, deforestation of the Congolese rainforest increased by 5%.[74]
The World Wildlife Fund's ecoregion project catalogues habitat types throughout the world, including habitat loss such as deforestation, showing for example that even in the rich forests of parts of Canada such as the Mid-Continental Canadian forests of the prairie provinces half of the forest cover has been lost or altered.
In 2011, Conservation International listed the top 10 most endangered forests, characterized by having all lost 90% or more of their original habitat, and each harboring at least 1500 endemic plant species (species found nowhere else in the world).[75]
As of 2015[update], it is estimated that 70% of the world's forests are within one kilometer of a forest edge, where they are most prone to human interference and destruction.[76][77]
Top 10 Most Endangered Forests in 2011[75] Endangered forest Region Remaining habitat Predominate vegetation type Notes Indo-Burma Asia-Pacific 5% Tropical and subtropical moist broadleaf forests Rivers, floodplain wetlands, mangrove forests. Burma, Thailand, Laos, Vietnam, Cambodia, India.[78] New Caledonia Asia-Pacific 5% Tropical and subtropical moist broadleaf forests See note for region covered.[79] Sundaland Asia-Pacific 7% Tropical and subtropical moist broadleaf forests Western half of the Indo-Malayan archipelago including southern Borneo and Sumatra.[80] Philippines Asia-Pacific 7% Tropical and subtropical moist broadleaf forests Forests over the entire country including 7,100 islands.[81] Atlantic Forest South America 8% Tropical and subtropical moist broadleaf forests Forests along Brazil's Atlantic coast, extends to parts of Paraguay, Argentina and Uruguay.[82] Mountains of Southwest China Zdroj:https://en.wikipedia.org?pojem=Tropical_deforestation
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