Question

Using complete sentences, explain how large-scale agriculture leads to increased atmospheric CO2.

Answer 1

Large-scale agriculture increases atmospheric CO2 primarily through land-use change and by accelerating the release of carbon stored in plants and soils. When forests, grasslands, or peatlands are cleared or burned to create cropland or pasture, the carbon in trees and vegetation is released as CO2 during burning and later decomposition. Intensive tillage of soils exposes previously protected soil organic matter to oxygen, which speeds microbial decomposition and releases CO2 from the soil. Draining and converting wetlands or peatlands for agriculture oxidizes peat and releases large amounts of long-stored carbon as CO2. The mechanization, irrigation, fertilizer manufacture, and transport associated with industrial agriculture rely heavily on fossil fuels, and the combustion of those fuels emits additional CO2. Large-scale monocultures and removal of perennial vegetation also reduce the landscape’s capacity to sequester carbon, so less CO2 is taken up from the atmosphere. Together, these processes shift carbon from land reservoirs into the atmosphere, increasing atmospheric CO2 concentrations.