In a paper published in the July 2006 issue of Global Change Biology, University of New Hampshire scientists George Hurtt, Steve Frolking, and coauthors show that land-use activities over the last 300 years have substantially altered the land surface in ways that are likely to have had profound effects on the Earth system. Land-use changes have impacted some 42-68 percent of the global land surface, according to the study, which used historical records, satellite data, and computer modeling to reconstruct 216 different global land-use reconstructions to derive the most comprehensive picture to-date.
"This is the first global land-use history description that's designed specifically to allow global carbon and climate models to assess the impacts of land-use history both on the past and current sources and sinks of carbon and climate," says Hurtt, assistant professor of natural resources at the UNH Institute for the Study of Earth, Oceans, and Space (EOS) and Department of Natural Resources.
According to Hurtt, this global land-use data will allow the next generation of coupled carbon-climate models, known as Earth-system models, to include the most advanced representations of land-use practices yet, including the first mapped estimates of the effects of shifting agriculture, logging, and secondary recovering lands.
"Land-use activities are known to have added large amounts of carbon dioxide to the atmosphere, altered surface reflectivity, and led to habitat alteration and destruction," says Hurtt. "A major challenge for scientists now is to understand the combined effects of these activities on the dynamics of the carbon-climate system. This study provides a key basis for these assessments."
Land-use history is critical to understanding the dynamics of the carbon-climate system, not just for technical reasons but also for policy reasons. One of the big policy debates is to what extent carbon sinks in ecosystems should be a
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Contact: George Hurtt
george.hurtt@unh.edu
603-862-4185
University of New Hampshire
13-Jul-2006