Deforestation

feedback cycles contributing to global warming. Global warming also puts increased pressure on communities who seek food security by clearing forests for agricultural use and reducing arable land more generally. Deforested regions typically incur significant other environmental effects such as adverse soil erosion and degradation into wasteland.

The resilience of human food systems and their capacity to adapt to future change is linked to biodiversity – including dryland-adapted shrub and tree species that help combat desertification, forest-dwelling insects, bats and bird species that pollinate crops, trees with extensive root systems in mountain ecosystems that prevent soil erosion, and mangrove species that provide resilience against flooding in coastal areas.[10] With climate change exacerbating the risks to food systems, the role of forests in capturing and storing carbon and mitigating climate change is important for the agricultural sector.[10]Definition
This screen shot shows a map that highlights countries based on their net change rate of forest area. Areas that appear more blue have a higher net change rate than areas that appear tan. Brown areas indicate a net loss of forest area.
Forest area net change rate per country in 2020
Deforestation is defined as the conversion of forest to other land uses (regardless of whether it is human-induced).[11]

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.[11]Impacts
On atmosphere and climate
Further information: Deforestation and climate change

Biophysical mechanisms by which forests influence climate.[152]

Per capita CO2 emissions from deforestation for food production

Illegal "slash-and-burn" practice in Madagascar, 2010

Mean annual carbon loss from tropical deforestation.[153]
Deforestation is a major contributor to climate change.[154][155][156] It is often cited as one of the major causes of the enhanced greenhouse effect. Recent calculations suggest that CO2 emissions from deforestation and forest degradation (excluding peatland emissions) contribute about 12% of total anthropogenic CO2 emissions, with a range from 6% to 17%.[157] A 2022 study shows annual carbon emissions from tropical deforestation have doubled during the last two decades and continue to increase: by 0.97 ± 0.16 PgC (petagrams of carbon, i.e. billions of tons) per year in 2001–2005 to 1.99 ± 0.13 PgC per year in 2015–2019.[158][153]

According to a review, north of 50°N, large scale deforestation leads to an overall net global cooling; but deforestation in the tropics leads to substantial warming: not just due to CO2 impacts, but also due to other biophysical mechanisms (making carbon-centric metrics inadequate). Moreover, it suggests that standing tropical forests help cool the average global temperature by more than 1 °C.[159][152]

The incineration and burning of forest plants to clear land releases large amounts of CO2, which contributes to global warming.[160] Scientists also state that tropical deforestation releases 1.5 billion tons of carbon each year into the atmosphere.[161]Prehistory
The Carboniferous Rainforest Collapse[9] was an event that occurred 300 million years ago. Climate change devastated tropical rainforests causing the extinction of many plant and animal species. The change was abrupt, specifically, at this time climate became cooler and drier, conditions that are not favorable to the growth of rainforests and much of the biodiversity within them. Rainforests were fragmented forming shrinking 'islands' further and further apart. Populations such as the sub class Lissamphibia were devastated, whereas Reptilia survived the collapse. The surviving organisms were better adapted to the drier environment left behind and served as legacies in succession after the collapse.[33][self-published source?]


An array of Neolithic artifacts, including bracelets, ax heads, chisels, and polishing tools.
Rainforests once covered 14% of the earth's land surface; now they cover a mere 6% and experts estimate that the last remaining rainforests could be consumed in less than 40 years.[267] Small scale deforestation was practiced by some societies for tens of thousands of years before the beginnings of civilization.[268] The first evidence of deforestation appears in the Mesolithic period.[269] It was probably used to convert closed forests into more open ecosystems favourable to game animals.[268] With the advent of agriculture, larger areas began to be deforested, and fire became the prime tool to clear land for crops. In Europe there is little solid evidence before 7000 BC. Mesolithic foragers used fire to create openings for red deer and wild boar. In Great Britain, shade-tolerant species such as oak and ash are replaced in the pollen record by hazels, brambles, grasses and nettles. Removal of the forests led to decreased transpiration, resulting in the formation of upland peat bogs. Widespread decrease in elm pollen across Europe between 8400 and 8300 BC and 7200–7000 BC, starting in southern Europe and gradually moving north to Great Britain, may represent land clearing by fire at the onset of Neolithic agriculture.

The Neolithic period saw extensive deforestation for farming land.[270][271] Stone axes were being made from about 3000 BC not just from flint, but from a wide variety of hard rocks from across Britain and North America as well. They include the noted Langdale axe industry in the English Lake District, quarries developed at Penmaenmawr in North Wales and numerous other locations. Rough-outs were made locally near the quarries, and some were polished locally to give a fine finish. This step not only increased the mechanical strength of the axe, but also made penetration of wood easier. Flint was still used from sources such as Grimes Graves but from many other mines across Europe.

Evidence of deforestation has been found in Minoan Crete; for example the environs of the Palace of Knossos were severely deforested in the Bronze Age.[272]