Earth Syst. Dynam. 10, 473–484 (2019)

Deforestation has complex feedbacks. Clearing trees can change surface brightness and the amount of sunlight reflected to space, modify the partitioning of surface latent and sensible heat, and affect land–atmosphere interaction. Clarifying the net impact of these processes on local temperature, however, is hindered by differences in how that is defined. Common options include surface temperature, measured at the ‘skin’ of the land surface, and 2-m temperature, representing a thermometer reading 2 m aloft.

Johannes Winckler of the Max Planck Institute for Meteorology, Germany, and colleagues investigate the impact of deforestation on these variables in climate models. Removing high-latitude trees decreases temperature locally at the surface and at 2 m in the annual mean, though with warming during local summer. Tropical deforestation, by contrast, leads to year-round warming, strongest at the surface. The magnitude of change between air and surface temperatures can differ by a factor of two. This highlights the importance of temperature definition when comparing models and observations, especially for policy-relevant impacts of land use change.