Ahead of Rio summit, U.N. report embraces ‘boundaries’: ‘Planetary boundaries has been seen as a successor to global warming, climate change or biodiversity as a top-level message’
'Proposed three years ago in the journal Nature, the boundaries are roughly based on the limits estimated during the past 10,000 years of human activity The endorsement of world leaders for such boundaries -- say, for example, a limit for atmospheric carbon dioxide, land-use change or biodiversity loss -- is expected to be a major rhetorical highlight of the Rio+20 summit'
