In a June 6 piece for E&E Publishing’s daily environmental news website Greenwire, associate professor Earl Ellis, geography and environmental systems, spoke with reporter Paul Voosen in regards to the U.N.’s release of its fifth Global Environmental Outlook (GEO-5) ahead of this month’s “Rio+20: United Nations Conference on Sustainable Development” to be held in Rio De Janeiro. The article focused on GEO-5’s emphasis on “planetary boundaries” as an important aspect of future environmental policy, which “are roughly based on the limits estimated during the past 10,000 years of human activity, and… have been seized upon by policymakers seeking a guide …