Peter M. Groffman is a Professor at the City University of New York Advanced Science Research Center and Brooklyn College, with research interests in ecosystem, soil, landscape and microbial ecology, with a focus on carbon and nitrogen dynamics. Specific recent research efforts include studies of nitrogen dynamics in urban watersheds, lawns, riparian zones and forests, winter climate change effects on nutrient cycling in forests, calcium/nitrogen/carbon interactions in forests, and the effects of exotic earthworm invasion on soil nitrogen and carbon cycling. Groffman was a Convening Lead Author for the 2013 U.S. National Climate Assessment Chapter on Ecosystems, Biodiversity and Ecosystem Services and a lead author for the Second (Wetlands) and Third (North America) Assessment Reports of the Intergovernmental Program on Climate Change (IPCC).