New Green Liberty Bonds are using a World War II strategy in the battle for the climate. What can be done in the face of an existential threat like climate change? Connecticut Green Bank looked to history for answers — and in July issued a green bond modeled after the patriotic bonds issued to fund the American military in World War II. Their bet: that individual investors will step up to help fight climate change just as Americans bought bonds to support the war efforts of the last century. The…