A report this week indicates that frackers are the second largest emitters of greenhouse gases in the US. But that does not account for the fact that the largest emitter – power plants – increasingly are run on natural gas. And the impact of methane on global warming is understated by 5x.
Fracking Seen by EPA as No. 2 Emitter of Greenhouse Gases
Natural gas and oil production is the second-biggest source of U.S. greenhouse gases, the government said, emboldening environmentalists who say tighter measures are needed to curb the emissions from hydraulic fracturing.
In its second-annual accounting of emissions that cause global warming from stationary sources, the U.S. Environmental Protection Agency for the first time included oil and natural- gas production. Emissions from drilling, including fracking, and leaks from transmission pipes totaled 225 million metric tons of carbon-dioxide equivalents during 2011, second only to power plants, which emitted about 10 times that amount.
The last line is a bit amusing, since most power plants run on either natural gas or coal. If the ones that burn gas are added to the fracking, that could put fracking and fracking related power production at the top of the global warming list.
But the EPA study understates the impact on methane emissions, since it uses an out-of-date methodology, as my pal Dr. Ingraffea relates:
“EPA-reported emissions are calculated and reported as what are called CO2eq, that means the emission of carbon dioxide, a greenhouse gas, plus other emissions, like methane (CH4) that are also greenhouse gases, converted to equivalent (hence the CO2eq symbol) amounts of CO2. The problem is that not all gases have the same effect on global warming. So, by convention, other greenhouse gases are rated according to their effect on warming relative to that of CO2. That rating is called the Global Warming Potential (GWP) which is the ratio of the heating potential of another gas relative to that of CO2.
Now, the Code of Federal Regulations (CFR), that EPA and other government agencies must follow, has encoded a GWP of 21 for methane. That number is based on science completed before about 1997, maybe earlier, and GWP’s are constantly evolving as more is understood about atmospheric chemistry and global warming. That number 21 is now 25 according to the IPCC (Intergovernmental Panel on Climate Change) report of 2007, and is now 33 according to the very latest peer-reviewed science. In other words, Federal law has not kept up with rapidly changing science by at least 15 years.
It gets worse. Those numbers, 21, 25, 33, also result from a policy assumption, not just science. Here is why: The GWP for methane depends very strongly on what period of time one wants to make the comparison with CO2. That is a policy judgment call. The numbers 21, 25, and 33 are for a 100-year time horizon, in other words, taken over a 100 year period, how much more heating will methane cause relative to CO2 over 100 years?
Since we measure generations in 20 year increments, who cares about 100 years if we are, as President Obama is now saying, (post Sandy) very concerned about the on-going acceleration of global warming over the next few decades? The latest climate science estimates predict we will most likely be at 2 degrees C global warming in about 40-50 years, and really bad things will happen well before 50 years. So, we should be looking at a shorter time horizon for GWP, right? Well, over a 20 year time horizon, the latest science says that the GWP for methane is as much as 105, not 21, not 25, not 33. In essence, the impact of methane acts faster on the atmosphere than CO2, and is understated by by 5x.
So, what does this mean regarding the EPA emissions announcement this week? That 225 million metric tons of emissions from oil and gas is a low estimate (it is not an actual measurement) consisting partly of CO2 and partly of methane, and they are converting the methane emissions to CO2 equivalent emissions using the artifact number 21: old science, short-sighted policy judgment.
The same reasoning applies to the issue of whether the U.S. has actuallly made progress on its own against global warming. You may have recently read that CO2 emissions have decreased over the last few years in the U.S. True, and significantly because total energy use in the U.S. has decreased, and renewables that do not emit CO2 have increased. But the CO2eq has increased from the U.S. over those years – because the U.S. is emitting more methane.”
The old saw about boiling a frog by slowly turning up the heat applies to global warming. Only if the frog is really really dumb and does not catch on that it’s getting cooked.