Deforestation and climate change
Deforestation is a primary contributor to climate change, and climate change affects the health of forests. Land use change, especially in the form of deforestation, is the second largest source of carbon dioxide emissions from human activities, after the burning of fossil fuels. Greenhouse gases are emitted from deforestation during the burning of forest biomass and decomposition of remaining plant material and soil carbon. Global models and national greenhouse gas inventories give similar results for deforestation emissions., deforestation is responsible for about 11% of global greenhouse gas emissions. Carbon emissions from tropical deforestation are accelerating.
When forests grow they are a carbon sink and therefore have potential to mitigate the effects of climate change. Some of the effects of climate change, such as more wildfires, invasive species, and extreme weather events can lead to more forest loss. The relationship between deforestation and climate change is one of a positive climate feedback. The more trees that are removed, the greater the effect of climate change which then
results in the loss of more trees.
Forests cover 31% of the land area on Earth. Every year, 75,700 square kilometers of the forest is lost. There was a 12% increase in the loss of primary tropical forests from 2019 to 2020.
Deforestation has many causes, among them agricultural clearcutting, livestock grazing, logging for timber, and wildfires.
Effects of deforestation on climate change
Irreversible deforestation would result in a permanent rise in the global surface temperature. Moreover, it suggests that standing tropical forests help cool the average global temperature by more than.Deforestation of tropical forests may risk triggering tipping points in the climate system and of forest ecosystem collapse which would also have effects on climate change.
Several studies since the early 1990s have shown that large-scale deforestation north of 50°N leads to overall net global cooling while tropical deforestation produces substantial warming. Carbon-centric metrics are inadequate because biophysical mechanisms other than impacts are important, especially the much higher albedo of bare high-latitude ground vis-à-vis intact forest.
Deforestation, particularly in large swaths of the Amazon, where nearly 20% of the rainforest has been clear cut, has climactic effects and effects on water sources as well as on the soil. Moreover, the type of land usage after deforestation also produces varied results. When deforested land is converted to pasture land for livestock grazing it has a greater effect on the ecosystem than forest to cropland conversions. Other effect of deforestation in the Amazon rainforest is seen through the greater amount of carbon dioxide emission. The Amazon rainforest absorbs one-fourth of the carbon dioxide emissions on Earth, however, the amount of absorbed today decreases by 30% than it was in the 1990s due to deforestation.
Modeling studies have concluded that there are two crucial moments that can lead to devastating effects in the Amazon rainforest which are increase in temperature by and deforestation reaching a level of 40%.
Forest fires
Statistics have shown a direct correlation between forest fires and deforestation. Statistics regarding the Brazilian Amazon area during the early 2000s have shown that fires and the air pollution that accompanies these fires mirror the patterns of deforestation and "high deforestation rates led to frequent fires".The Amazon rainforest has experienced fires inside the forest as well as wildfires on its outer edges. Wetlands have faced an increase in forest fires as well. Due to the change in temperature, the climate around forests have become warm and dry, conditions that allow forest fires to occur.
Under unmitigated climate change, by the end of the century, 21% of the Amazon would be vulnerable to post‐fire grass invasion. In 3% of the Amazon, fire return intervals are already shorter than the time required for grass exclusion by canopy recovery, implying a high risk of irreversible shifts to a fire‐maintained degraded forest grassy state. The south‐eastern region of the Amazon is currently at highest risk of irreversible degradation.
According to a study in tropical peatland forest of Borneo, deforestation also contributes to the increase in fire risk.
Changes in rainfall
As a consequence of reduced evapotranspiration, precipitation is also reduced. This implies having a hotter and drier climate, and a longer dry season. This change in climate has drastic ecological and global impacts including increases in severity and frequency of fires, and disruption in the pollination process that will likely spread beyond the area of deforestation.According to a study published in 2023, tropical deforestation has led to a significant decrease in the amount of observed precipitation. By the year 2100, researchers anticipate that deforestation in the Congo will diminish regional precipitation levels by up to 8-10%.