Land use, land-use change, and forestry (LULUCF), also referred to as Forestry and other land use (FOLU), is defined by the United Nations Climate Change Secretariat as a "greenhouse gas inventory sector that covers emissions and removals of greenhouse gases resulting from direct human-induced land use such as settlements and commercial uses, land-use change, and forestry activities."^[1]

LULUCF has impacts on the global carbon cycle and as such, these activities can add or remove carbon dioxide (or, more generally, carbon) from the atmosphere, influencing climate.^[2] LULUCF has been the subject of two major reports by the Intergovernmental Panel on Climate Change (IPCC), but is difficult to measure.^[3]: 12 Additionally, land use is of critical importance for biodiversity.^[4]

Climate impacts

Per capita greenhouse gas emissions by country including land-use change, in the year 2000 according to World Resources Institute

Land-use change can be a factor in CO₂ (carbon dioxide) atmospheric concentration, and is thus a contributor to global climate change.^[5] IPCC estimates that land-use change (e.g. conversion of forest into agricultural land) contributes a net 1.6 ± 0.8 Gt carbon per year to the atmosphere. For comparison, the major source of CO₂, namely emissions from fossil fuel combustion and cement production, amount to 6.3 ± 0.6 Gt carbon per year.^[6]

In 2021 the Global Carbon Project estimated annual land-use change emissions were 4.1 ± 2.6 Gt CO2 (CO2 not carbon: 1 Gt carbon = 3.67 Gt CO2 ^[7]) for 2011-2020.^[8]

This decision sets out the rules that govern how Kyoto Parties with emission reduction commitments (so-called Annex 1 Parties) account for changes in carbon stocks in land use, land-use change and forestry.^[9] It is mandatory for Annex 1 Parties to account for changes in carbons stocks resulting from deforestation, reforestation and afforestation (B Article 3.3)^[10] and voluntary to account for emissions from forest management, cropland management, grazing land management and revegetation (B. Article 3.4).^[9]

The land-use sector is critical to achieving the aim of the Paris Agreement to limit global warming to 2 °C (3.6 °F).^[11]

The impact of land-use change on the climate is also more and more recognized by the climate modeling community. On regional or local scales, the impact of LUC can be assessed by Regional climate models (RCMs). This is however difficult, particularly for variables, which are inherently noisy, such as precipitation. For this reason, it is suggested to conduct RCM ensemble simulations.^[12]

Extents and mapping

Share of the total land surface without and with consideration of multiple changes between six major land use/cover categories (urban area, cropland, pasture/rangeland, forest, unmanaged grass/shrubland, non-/sparsely vegetated land) in 1960–2019.^[13]

A 2021 study estimated, with higher resolution data, that land-use change has affected 17 % of land in 1960-2019, or when considering multiple change events 32 %, "around four times" previous estimates. They also investigate its drivers, identifying global trade affecting agriculture as a main driver.^[14][13]

Forest modeling

Traditionally, earth system modeling has been used to analyze forests for climate projections. However, in recent years there has been a shift away from this modeling towards more of mitigation and adaptation projections.^[15] These projections can give researchers a better understanding of what future forest management practices should be employed. Furthermore, this new approach to modeling also allows for land management practices to be analyzed in the model. Such land management practices can be: forest harvest, tree species selection, grazing, and crop harvest. These land management practices are implemented to understand their biophysical and biogeochemical effects on the forest. However, there is a major lack of available data for these practices currently, so there needs to be further monitoring and data collecting to help improve the accuracy of the models.^{[citation needed]}