Boston Globe: Former Vice President Al Gore challenged Americans yesterday to switch all of the nation’s electricity production to wind, solar, and other carbon-free sources within 10 years, a goal that he said would solve global warming as well as economic and natural security crises caused by dependence on fossil fuels. “The answer is to end our reliance on carbon-based fuels,” Gore told a packed auditorium in Washington’s historic Constitution Hall. “When you connect the dots, it …