Fig. 1. Terrestrial ecosystems affect the climate system by influencing the exchange of greenhouse gases between the land surface and the atmosphere (biogeochemical regulation) and by influencing the exchange of energy (evapotranspiration and albedo) with the atmosphere (biophysical regulation). Biogeochemical processes affect the concentration of greenhouse gases in the atmosphere, influencing global climate on decadal time scales or longer, whereas biophysical processes cause local cooling or warming over days and months. Credit: Evan DeLucia