This Environmental Research Letters study should be sobering to fans of expanded gas use who care about global warming — such as the Environmental Defense Fund and President Obama — because it is true even if methane leakage from gas production and delivery could somehow miraculously be reduced to zero.
“Natural gas has been presented as a bridge to a low-carbon future, but what we see is that it’s actually a major detour,” explained lead author Christine Shearer in the news release. “We find that the only effective paths to reducing greenhouse gases are a regulatory cap or a carbon tax.”
Although many fracking advocates pretend otherwise, this is not a new finding. Indeed, most claims that shale gas will significantly reduce U.S. carbon emissions in the future are based on little more than hand-waving and wishful thinking, as the literature makes clear. That’s because — even if we ignore methane leaks — those claims assume natural gas is replacing coal only, rather than replacing some combination of coal, renewables, nuclear power, and energy efficiency, which is what is happening in the real world.
Last year, Stanford’s Energy Modeling Forum published the results of economic modeling by more than a dozen different expert teams. The figure below shows the results of the models that extend to 2050 (though the results are not substantially different if the modeling stops at 2035).
Why doesn’t cheap, abundant natural gas matter much for long-term U.S. CO2 trends? Over time, and especially post-2020, “natural gas begins to displace nuclear and renewable energy that would have been used otherwise in new power plants under reference case conditions.”
“Cutting greenhouse gas emissions by burning natural gas is like dieting by eating reduced-fat cookies,” explains Prof. Steven Davis, the principal investigator of the new study. “It may be better than eating full-fat cookies, but if you really want to lose weight, you probably need to avoid cookies altogether.”
To extend the metaphor, those reduced-fat cookies are not simply replacing full-fat ones, they are also replacing fruits and other healthy snacks.
Dr. Shearer explains the study’s findings in this video:
It bears repeating that natural gas is mostly methane, (CH4), a super-potent greenhouse gas, which traps 86 times as much heat as CO2 over a 20-year period. So even small leaks in the natural gas production and delivery system can have a large climate impact .
Observations and analysis make clear that methane leakage is actually quite high — enough to gut the entire benefit of switching from coal-fired power to gas for decades. Sadly, the kind of national regulations that could seriously cut leakage are not in our foreseeable future.
Memo To Obama: Expanded Natural Gas Use Worsens Climate Change - by Joe Romm
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