At the Glasgow climate summit, nearly 200 countries signed onto a final decision that mentioned fossil fuels for the very first time. They agreed to phase out “inefficient” fossil fuel subsidies. In Glasgow, US Climate Envoy John Kerry called these subsidies “the definition of insanity,” and there’s widespread acknowledgment that the hundreds of billions of dollars a year in government support for fossil fuel energy is a roadblock to reducing greenhouse gas emissions. But G20 countries signed on to a similar pledge more than a decade ago and little has changed. The World’s environment correspondent Carolyn Beeler reports on why subsidies for coal, oil and natural gas are so hard to kick, and whether the Glasgow pact might impact their future.