Erle Ellis, 47, is an associate professor of geography and environmental systems at the University of Maryland, Baltimore County. He writes the blog Human Landscapes ( ecotope.org/blogs) and tweets as @erleellis. Questions and answers have been edited.
Q: You write about land-use changes. What are some of the changing land-use patterns on the East Coast?
At least two major land change processes have been playing out since the 1950s and the development of the highway system: urban sprawl and cropland abandonment. Cropland abandonment is occurring partly because industrial agriculture is most profitable in, and is becoming more concentrated in, the best agricultural lands, and because land prices continue to rise as suburbs and exurbs expand into agricultural areas. Sprawl and cropland abandonment tend to be somewhat coupled in this region, but not always. Both processes tend to increase tree cover, because both residential developments and abandoned croplands end up with greater tree cover than croplands in active use.
Q: What's your take on geo-engineering solutions to climate change?
I am not entirely against geo-engineering, and my reasons for caution are not because I believe that humans must leave nature alone (way too late for that). Geo-engineering could make sense as a last-ditch effort to avoid some of the worst consequences. But altering the climate system intentionally by just about any of the options being considered could initiate global changes far worse than increasing temperatures.
Q: You've argued that the age of wild biospheres has come to an end and that we're now in a geologically defined age where the biosphere is managed by people. When and how did this shift happen?
Direct human alteration of the terrestrial biosphere by land clearing, hunting and other means has been significant for more than 8,000 years. However, only in the past century have human populations and their use of land transformed the majority of the terrestrial biosphere into intensively managed landscapes with predominantly novel anthropogenic ecological processes. We are now in a new geological epoch defined by human systems.
