Dr F Stuart Chapin, III

Much of my current research deals with ecosystem water and energy exchange and the ways that changes in vegetation caused by climate warming or a change in fire regime might alter regional and global climate. The research involves a mixture of observations of different ecosystems made with micrometeorological measurements (eddy covariance) and field manipulations. In general, we find large differences in energy exchange among ecosystem types in both tundra and boreal forest. If vegetation changes as expected (shrubs and trees becoming more abundant in tundra, and fires becoming more frequent and severe in boreal forest), this would cause about a substantial increase in summer air temperature in tundra, which would act as a positive feedback to enhance these vegetation changes but a negative feedback in boreal forest. Our field experiments show that many of these vegetation changes could occur quite quickly--within a decade.