“What we’re facing worldwide really is a planetary emergency,” Gore said. “I’m optimistic, but we’re losing this battle badly.”

That’s in an article about Al Gore at the Aspen Institute.

It’s going to take a 90-percent decrease in carbon emissions from developed fossil fuel guzzlers like the U.S. and a 50-percent decrease worldwide to get a handle on the problem, Gore said — changes that will take major leaps of political will far beyond what current politicians see as feasible. That reduction, which would be mandated by a world-wide treaty, could happen through carbon taxes, cap and trade, technological innovations, and energy conservation and efficiency, he continued, as long as it is accompanied by a major grassroots public shift to sustain it at the level necessary.