Human conversion of forest ecosystems to agriculture is a major driver of global change. Conventionally, the impacts of the historical cropland expansion on Earth’s radiation balance have been quantified through two opposing effects: the release of stored carbon to the atmosphere as CO2 (warming) versus the increase in surface albedo (cooling).

Human burning of fossil fuels and biofuels for energy use affects global climate change through increasing carbon dioxide (CO2), but also a host of other short-lived non-CO2 effects that are complex and involve impacts that are both warming and cooling.