Wealthy donors spent about a half billion dollars helping green groups try to pass climate legislation and prep the guts of a new international global warming treaty.

With both efforts in tatters, donors behind the green curtain are trying to figure out what’s next as well as asking whether the money could have been better spent on other issues that were shoved to the sidelines over the past two years.

Donors are also hurling tough questions at their friends in the Obama administration about the White House’s failed climate push despite the foundations giving unprecedented amounts of money to the cause as their stock portfolios plummeted during the recession.