Are we being prepped for the claim that left-wingers prevented the planet from overheating?

The Incredible Shrinking Carbon Pollution Forecast | Dan Lashof's Blog | Switchboard, from NRDC

There is plenty of bad news about global warming, but the 40% reduction in the business-as-usual forecast we have seen in the last few years makes the 80% or more reduction in actual emissions we need by 2050 look a whole lot more feasible.