CAMBRIDGE – Against all expectations, US emissions of carbon dioxide into the atmosphere, since peaking in 2007, have fallen by 12% as of 2012, back to 1995 levels. The primary reason, in a word, is “fracking.” Or, in 11 words: horizontal drilling and hydraulic fracturing to recover deposits of shale gas.
No other factor comes close to providing a plausible explanation. Unlike the European Union, the US never ratified the Kyoto Protocol, in which participating countries committed to cut CO2 emissions by roughly 5%, relative to 1990 levels, by 2012. Nor is America’s continued emissions reduction a side effect of lower economic activity: While the US economy peaked in late 2007, the same time as emissions, the recession ended in June 2009 and GDP growth since then, though inadequate, has been substantially higher than in Europe. Yet US emissions have continued to fall, while EU emissions began to rise again after 2009.
One can virtually prove that shale gas has been the major influence driving the fall in US emissions. Just ten years ago, the natural-gas industry was so sure that domestic production was reaching its limit that it made large investments in terminals to import liquefied natural gas (LNG). Yet fracking has increased supply so rapidly that these facilities are now being converted to export LNG.
Natural gas emits only half as much CO2 as coal, and occupies a rapidly increasing share of electricity generation – up 37% since 2007, while coal’s share has plummeted by 25%. Indeed, natural gas has drawn close to coal as the number one source of US power. Renewables still constitute only 5% of power generation in the US – less than hydroelectric and far less than nuclear, let alone coal or gas.