Natural Gas & Climate Change

By Bernie Fischlowitz-Roberts

Gov. Jay Inslee (D-WA): “We are the first generation to feel the sting of climate change, and we are the last generation that can do something about it.”

Context
Earlier this year, the world reached 400 parts per million (ppm) of CO2 in the atmosphere. James Hansen, NASA’s former chief climate scientist, has said: “if humanity wishes to preserve a planet similar to that on which civilization developed and to which life on Earth is adapted… CO2 will need to be reduced…to at most 350 ppm.”

Many of the world’s governments have given lip service to the notion of limiting warming to 2 degrees Celsius. Though it would not return levels of atmospheric CO2 to 350 ppm, it would give humanity a chance of avoiding utter catastrophe. Achieving that goal requires leaving at least 80% of known fossil fuel reserves in the ground and out of world markets. The latest National Climate Assessment, released in May by the White House, makes clear that climate impacts are already significant, and are likely to get much worse in the absence of concerted efforts to reduce emissions.

Natural Gas & Climate Change
Over the last several years, as prices for natural gas (NG) have fallen, the share of our national electric generation from coal has fallen dramatically, with NG the primary replacement. Looking solely at GHG emissions from power plant combustion, conventional wisdom has long held that this fuel substitution could provide climate benefits, since NG produces about half the GHG emissions per unit of energy generated as coal. However, the share of NG derived from fracking and horizontal drilling—which rose from 3% in 2005 to 35% in 2012, and is predicted to be almost 50% by 2035—complicates the analysis [1].

In addition, a number of recent studies have concluded that the life cycle GHG emissions from both shale gas and traditional NG actually exceed those of traditional oil or coal, primarily due to previously underestimated methane emissions. (Methane is a more powerful greenhouse gas than CO2 by a factor of 50-105 for a 20-year time horizon, and by a factor of 20-35 on a 100-year time scale[2].)

Implications
There are several primary implications of these findings. First, the notion of NG as a “bridge fuel” to a lower-carbon future seems dubious at best. Second, these findings further reinforce the ecological and economic dangers of continued investment in NG extraction and use. In the last five years, clean energy jobs have grown twice as fast as any other sector in the U.S.[3] Thus, capital-intensive NG investment not only exacerbates climate change, but also hinders job creation by displacing necessary investment in more labor-intensive clean, renewable forms of energy.

Third, since the climate system is more immediately responsive to methane and other shorter-lived GHGs like black carbon than to CO2, efforts to reduce methane emissions in the next two decades should be as high a priority as longer-range reductions in CO2. This means not only reducing production and consumption of NG (and all fossil fuels), but also eating more plant foods and fewer animal products, since animal agriculture is responsible for 37% of global methane emissions[4].

In the last several years, discussion of the links between food policy and climate change has become more prominent. In 2006, the UN Food and Agriculture Organization (FAO) calculated that animal agriculture contributed 18% of global GHG emissions, larger than the world’s entire transportation sector[5]. A 2009 analysis co-authored by the World Bank’s former chief environmental adviser re-evaluated the FAO data and suggested the share of global GHG emissions attributable to animal agriculture was actually 51%[6].

References

  1. Robert Howarth, “A bridge to nowhere: methane emissions and the greenhouse gas footprint of natural gas,” Energy Science & Engineering, 2014, p. 1. http://www.eeb.cornell.edu/howarth/publications/Ho....
  2. Ibid, p.7
  3. Washington Gov. Jay Inslee, remarks at Climate Solutions fundraising breakfast in Seattle, 5/19/14.
  4. Martin Rowe, “The Environment and Animal Agriculture,” presentation to Boston Vegetarian Food Festival, 10/30/10.
  5. United Nations Food and Agriculture Organization, “Livestock’s Long Shadow: environmental issues and options,” 2006.
  6. Robert Goodland and Jeff Anhang, “Livestock and Climate Change,” World Watch, November/December 2009, pp. 10-19. http://www.worldwatch.org/files/pdf/Livestock%20an...