Ruth DeFries’ research examines human transformation of the landscape and its consequences for climate, biogeochemical cycling, biodiversity, and other ecosystem services that make our planet habitable. The work is based on the premise that land use change involves tradeoffs between human necessities such as food and unintended environmental consequences such as greenhouse gas emissions and habitat loss. A particular focus is tropical deforestation and its impacts on atmospheric carbon emissions and conservation. The research analyzes land use changes over broad scales through the lens of satellite observations. She is actively involved in linking scientific information into policy decisions.