In addition to being the primary constituent of natural gas, methane is itself a powerful greenhouse gas. Indeed, it is one of the reasons why livestock agriculture and landfills contribute to climate change.
As discussed in The New York Times, one reason why the expanded production of natural gas is worrisome from a climatic perspective is that drilling for and extracting gas causes some of it to leak directly into the atmosphere. These are called ‘fugitive emissions’. According to the article, as much as 7.9% of the gas extracted from shale gas wells is released directly into the atmosphere in this way.
Of course, the gas that is put through pipelines and burned for heat or electricity is also problematic from a climate change perspective. One molecule of methane (CH4) combines with two molecules of oxygen (O2) to form one molecule of carbon dioxide (CO2) and two molecules of water (H2O). That basically means that for every cubic metre of natural gas that gets burned, a cubic metre of carbon dioxide gets added to the atmosphere.
The article repeatedly quotes Robert Howarth, a professor of ecology and environmental biology at Cornell University. He points out several studies that identify the problematic effects of natural gas production on the Earth’s climate, concluding that “[w]hen all is factored together… the greenhouse gas footprint of shale gas can be as much as 20 percent greater than, and perhaps twice as high as, coal per unit of energy”.
That certainly raises questions about the idea that natural gas is a clean-burning fuel that can help us deal with climate change.
When US government scientists began sampling the air from a tower north of Denver, Colorado, they expected urban smog â€” but not strong whiffs of what looked like natural gas. They eventually linked the mysterious pollution to a nearby natural-gas field, and their investigation has now produced the first hard evidence that the cleanest-burning fossil fuel might not be much better than coal when it comes to climate change.
Led by researchers at the National Oceanic and Atmospheric Administration (NOAA) and the University of Colorado, Boulder, the study estimates that natural-gas producers in an area known as the Denver-Julesburg Basin are losing about 4% of their gas to the atmosphere â€” not including additional losses in the pipeline and distribution system. This is more than double the official inventory, but roughly in line with estimates made in 2011 that have been challenged by industry. And because methane is some 25 times more efficient than carbon dioxide at trapping heat in the atmosphere, releases of that magnitude could effectively offset the environmental edge that natural gas is said to enjoy over other fossil fuels.