Excerpts : At the most fundamental level, the ecological footprint incorporates six measurements—city cover, carbon dioxide pollution, farm fields, fisheries, forests and rangeland—to reveal the aggregate area of land and water ecosystems required by specified human populations to produce the ecosystem goods and services they consume and to assimilate their carbon waste. Or so goes the definition from William Rees, an urban planning researcher at the University of British Columbia, and Mathis Wackernagel, head of the Global Footprint Network, who teamed up to develop the metric. The alternative that Kareiva prefers is what he calls an Earth genome project—a compilation of data that gets down to the local level on water use, soil degradation and, yes, greenhouse gas and other air pollution. Such a system would reveal whether the local water table was falling or if grazing was too intensive on a given landscape—exactly the type of judgments that the global ecological footprint is ill-suited to make. You could overgraze an arid land and convert it permanently to desert—thats a local threshold, Kareiva explains. We need to look for thresholds because they tell us the risk of the next degree of degradation. The ecological footprint can, however, reveal important connections on the national and international levels, Rees and Wackernagel point out. So, for example, even though Canadians have a small footprint, Canadas excesses of cropland, forest and fisheries are essentially exported to countries like the U.S. and China, which have oversize footprints. Most countries are in ecological deficit, increasingly dependent on potentially unreliable trade in biocapacity, Rees and Wackernagel wrote. What could possibly be gained from ignoring footprint assessments? scientificamerican/article.cfm?id=humans-not-using-more-than-one-planet&WT.mc_id=SA_Facebook
Posted on: Sat, 09 Nov 2013 21:42:55 +0000
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