I don't mean this to sound like an advertisement, but as both someone who actually cares about this planet AND a boardgamer, I thought I'd pass along news of a new game called Terra from a company called Days Of Wonder.
From their site: Terra puts the players in front of ecological, socio-economical and diplomatic-military crises where all must collaborate to save the Earth's fragile equilibrium while moving their own interests forward. Players score points for solving a crisis for the common good, but at the same time keeping as many scarce resources to themselves as they can.
This has been designed by one of my favorite game designers, Bruno Faidutti (if you're a gamer, you know him as the guy who designed a great game called Citadels).
Anyway, just wanted to pass along the info!
Oh, the site is www.terracrisis.com