The shale gas boom has led to a big drop in US carbon emissions, as generators switch from coal to cheap gas.
According to the International Energy Agency, US energy-related emissions of carbon dioxide, the main greenhouse gas, have fallen 450m tonnes over the past five years – the largest drop among all countries surveyed.
Fatih Birol, IEA chief economist, attributed the fall to improvements in fuel efficiency in the transport sector and a “major shift” from coal to gas in the power sector. “This is a success story based on a combination of policy and technology – policy driving greater efficiency and technology making shale gas production viable,” Mr Birol told the Financial Times.
Shale gas has transformed the US energy landscape, with surging production pushing gas prices down to 10-year lows and heralding an industrial renaissance. But it is also the subject of a heated environmental debate, with critics alleging that the production process can pollute groundwater.
Gas is fast becoming the new fuel of choice for the US power sector: in the past 12 months, coal generation has slumped by 19 per cent while gas generation has increased by 38 per cent, according to US Department of Energy figures. A gas-fired plant produces half the CO2 emissions of a coal-fired one.
Overall, however, the IEA said 31.6 gigatonnes of CO2 were released into the atmosphere last year, mainly through the burning of fossil fuels – one gigatonne more than in 2010 and much higher than the average annual increase of 0.6 GT between 2006 and 2010. “The impact of this increase is going to be catastrophic,” said John Sauven, executive director of Greenpeace. “We’ve really got to act now, with a real sense of urgency – which up till now has been completely lacking.”
The increase will make it harder to keep global temperatures from rising more than 2 degrees Celsius above pre-industrial levels – which scientists believe is the threshold for potentially “dangerous climate change”.