Last week the EPA proposed that carbon dioxide be considered one of six greenhouse gases which endanger the public health and welfare of US citizens. Well, it’s about time! The EPA is now seeking public comment on the proposed ruling, which consists of two parts: that the six greenhouse gases contribute to a litany of climate-related problems, and that motor vehicle emissions send four of those gases into the atmosphere. What could this mean for CO2-intensive energy sources, and what are some implications for clean energy?