Environmentalists were there to lighten their ecological footprint. Neocons were there to lighten the fat Saudi pocketbook, full of petro dollars that fund terrorism. According to Robert Bryce, writing in Slate, the strange bedfellows have come together to advocate measures that would increase car fuel efficiency, lessen foreign oil dependence, and pump up renewables.
While Bryce pitches the "sleeping with the enemy" angle, the key point is there are multiple, compelling reasons to aggressively pursue (and for the government to subsidize) energy efficiency, renewables and alternatives to fossil fuels, and reduced dependence on overseas oil. Greens have often worked this issue with one hand tied behind their backs.