The world’s carbon intensity of energy, namely the amount of CO2 spewed into the air for each unit of energy consumed, has not budged much Kyoto was held, 20 years ago. Even among the highly industrialized nations in the OECD, the carbon intensity of energy has declined by a paltry 4% since then, according to the International Energy Agency. This statistic, alone, puts a big question mark over the 100% renewable strategies deployed around the world to replace fossil energy. In a nutshell: Perhaps 100% renewables are not the answer.
Read more of this analysis by Eduardo Porter at the New York Times: “Wind and Solar power Advance, but Carbon Refuses to Retreat.”