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.