Twenty years ago the world met in Rio to save the planet - with mixed results. June sees a major re-gathering - 'Rio+20: UN Conference on Sustainable Development' - which might decide a new course. The event is set to be heated and contentious. On the one side, corporations and the UN will be pushing a new 'Green Economy' agenda that emphasizes economic growth, technology and market based approaches. On the other, indigenous groups and many NGOs from both North and South will be promoting a human and nature-rights agenda that calls for a radical shift away from privatizing and commodifying the natural environment and towards protecting the global commons.