The final day of the Aspen Environment Forum opened with a session entitled “Rio + 20 and the Making of a Global Green Economy,” (see video) which looked ahead to the United Nations Conference on Sustainable Development set for June of next year in Brazil. Panelists discussed the prospects for that conference and what needs to be achieved.

Toward the end of the session, Hari Sreenivasan of PBS NewsHour sent out this tweet: “Perhaps a rude question for this panel on Rio — are there any metrics that prove these global meetings ever matter?”

I’m not sure the question was answered in that Thursday session (or on Twitter) but it was a provocative one. Do