page_title: Deforestation and climate change
section_title: Agricultural expansion
hierarchical_section_title: Deforestation and climate change / Causes of deforestation / Agricultural expansion
caption_attribution_description: Anthropogenic biomes datasets describe potential natural vegetation, biomes, as transformed by sustained by human population density and land use including agriculture and urbanization. Anthropogenic biome categories (Anthromes) are defined by population density and land-use intensity. The data consists of 19 anthrome classes in six broad categories.
context_page_description: Deforestation is a primary contributor to climate change. Land use changes, especially in the form of deforestation, are the second largest anthropogenic source of atmospheric carbon dioxide emissions, after fossil fuel combustion. Greenhouse gases are emitted during combustion 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. As of 2019, deforestation is responsible for about 11% of global greenhouse gas emissions. Peatland degradation also emits GHG. Growing forests are a carbon sink with additional potential to mitigate the effects of climate change.
  Some of the effects of climate change, such as more wildfires, may increase deforestation.
  Deforestation comes in many forms: wildfire, agricultural clearcutting, livestock ranching, and logging for timber, among others. The vast majority of agricultural activity resulting in deforestation is subsidized by government tax revenue. Forests cover 31% of the land area on Earth and annually 75,700 square kilometers of the forest is lost.
context_section_description: The largest cause of deforestation and acute degradation is agriculture. According to Wageningen University and Research Centre, more than 80% of deforestation can be contributed to agriculture.  Forests are being converted to plantations for coffee, tea, palm oil, rice, rubber, and various other popular products. The rising demand for certain products and global trade arrangements causes forest conversions, which ultimately leads to soil erosion. The top soil oftentimes erodes after forests are cleared which leads to sediment increase in rivers and streams. Over time, land used for agricultural purposes degrades, resulting in unusable land which causes producers to need to find new productive lands. Moreover, agricultural expansion plays a role in coupled systems that cause climatic effects that reach far beyond agricultural croplands. Environmental factor#Socioeconomic Drivers
  Most deforestation also occurs in tropical regions. However, studies have shown that non-tropical forests will also see consequences from deforestation as new pressures from climate change warms areas that were once uninhabitable or too frigid to be arable. The estimated amount of total land mass used by agriculture is around 38%. The main drivers of deforestation in relation to agriculture are population growth and the increased pressures for agricultural expansion. Deforestation is linked with CO₂ emissions, in part due from crops having a relatively less impressive carbon storage per unit area then wooded areas or forests. Agricultural deforestation can take different forms, the most salient of which are the commercial plantations in tropical regions.
  Another prevalent method of agricultural deforestation is slash-and-burn agriculture, which was primarily used by subsistence farmers in tropical regions but has now become increasingly less sustainable. The method does not leave land for continuous agricultural production, but instead cuts and burns small plots of forest land which are then converted into agricultural zones. The farmers then exploit the nutrients in the ashes of the burned plants. This method is not sustainable because the plots can only be tilled for 2–3 years, where after farmers will move to a different plot and repeat the process. This process will be repeated about 5 to 10 times before a farmer would return to a patch of once deforested land allowed to return to a forested state. If land is not available, the length of time between cycles can be shortened leading to less nutrients in the soil. This lack of nutrients can then lead to smaller crop yields and a need to convert more forest land into agricultural zones. The repeated cycle of low yields and shortened fallow periods eventually results in less vegetation being able to grow on once burned lands and a decrease in average soil biomass. In small local plots sustainability is not an issue because of longer fallow periods and lesser overall deforestation. The relatively small size of the plots allowed for no net input of CO2 to be released. With the increased pressure to expand agricultural production this method has been used on a much larger scale then traditional subsistence farming. Slash-and-burn agriculture accounts for about 30% of all global arable land.  
  Researchers Offiong and Ita question whether increased food production through cropland expansion would be possible without resulting in greater climatic impacts. This is posited given that deforested soil is often unsatisfactory for growing crops. Poor quality soil would require extensive modifications and amendments through, primarily, the use of chemical fertilizers. The chemical based alterations along with contemporary farming practices would lead to erosion and soil depletion unless continually treated with these substances. These repeated practices would create an unsustainable cycle needed to keep producing expected yields.
  Deforestation without reforestation, has negative climatic effects but particularly for agricultural expansion, it creates a scenario for diminishing returns.  As noted by Offioing a
caption: Anthropogenic Biomes of the World
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