The letter from Range Resources’s Laural Ziemba on Nov. 1 made the correct claim that burning natural gas is preferable to coal with regard to carbon dioxide emissions. However, her statement that "Operators in the Marcellus and elsewhere have helped reduce our country’s use of coal by almost 40% since 2008, bringing America’s CO2 levels to their lowest in 20 years" is not correct and may possibly be a misstatement.
According to the Natural Gas Industry’s “EnergyINDepth” trade group studies, the switch from coal to natural gas from Appalachia has reduced CO2 emissions for power production by 30% since 2005, a laudable result. Unfortunately, the levels of CO2 both in Pennsylvania and over the globe have continued to increase unabated since 2005, and are now at their highest levels ever, and the rate of increase is growing.
I work as an atmospheric scientist and have personally measured these increasing CO2 levels using a NASA weather satellite over the last 17 years, a result which is completely verified by a large number of ground-based measurements of CO2 by the National Oceanic and Atmospheric Administration. Switching to natural gas helps, but all fossil-fuel energy sources are still contributing to the rise in CO2 levels.
This is not a time to rest on our laurels with regard to the fast pace of climate warming.