An unrestrained global fracking boom that unleashes plentiful and cheap gas will not tackle global warming by replacing coal and cutting carbon emissions, according to a comprehensive analysis that takes into account the impact on the rest of the energy supply.
Burning natural gas produces half the carbon dioxide released by coal, and shale gas proponents argue that gas can therefore be a “bridge” fuel, curbing emissions while very low carbon sources such as renewable and nuclear energy are ramped up.
But a new analysis published in the journal Nature shows that a gas boom would cut energy prices, squeezing out renewable energy, and is likely to actually increase overall carbon emissions. The researchers conclude that only new interventions, such as a long-sought international climate change deal or significant global price on carbon pollution, would be effective in tackling warming.
“The upshot is that abundant natural gas alone will not rescue us from climate change,” said Haewon McJeon, an economist at the US department of energy’s Pacific Northwest National Laboratory (PNNL), who led the research. “ technology could double or triple the global natural gas production by 2050. But greenhouse gas emissions would continue to grow in the absence of climate policies that promote lower carbon energy sources.”
Abundant gas may have a lot of benefits, such as economic growth, cutting coal-related local air pollution and energy security, McJeon said, but slowing climate change is not one of them.
The new research involved teams of scientists from the US, Australia, Austria, Germany and Italy, who developed five independent computer models to assess how carbon emissions between now and 2050 would be affected by a global gas boom. The “integrated assessment” models included energy production and use, economic activity and the Earth’s climate system.
The researchers found an unrestricted gas boom could increase the use of the fuel by 170% by 2050, but that this could actually increase overall CO2 emissions. The impact of a gas boom on CO2 emissions ranged from a small cut of 2% to an increase of 11%.
“We were surprised how little difference abundant gas made to total greenhouse gas emissions, even though it was dramatically changing the global energy system,” said James Edmonds, also at PNNL. “All five modelling teams reported little difference in climate change.”
Another member of the research team, Nico Bauer at the Potsdam Institute for Climate Impact Research (PIK) in Germany, said. “The high hopes that natural gas will help reduce global warming because of [lower emissions than] coal turn out to be misguided because market effects dominate.”
The lack of impact of a gas boom on cutting carbon emissions in the models was due to the lower cost of abundant gas, meaning it replaced renewables and nuclear energy as well as coal. The lower cost also meant people used more energy and discouraged energy efficiency measures. Furthermore, methane is a potent greenhouse gas and the leaks from drilling operations, even at the lower end of current estimates, would significantly drive climate change, the researchers found.
“The paper uncovers a serious crack in the gas bridge,” said Steven Davis and Christine Shearer, at the University of California, Irvine, in a comment article for Nature. “In the absence of new climate policies, increased supplies of natural gas could actually delay decarbonisation of the global energy system.”
But they added: “If we get the technologies and the policies right, natural gas might help us to cut emissions by working with renewable energy sources, rather than against them.”
Fracking has transformed energy production in US and has contributed to a decline in the country’s carbon emissions between 2007 and 2012, although renewables and energy efficiency contributed more. The shale gas boom has also had the knock-on effect of making US coal cheaper and driving up exports.
A recent report from the Intergovernmental Panel on Climate Change found that shale gas could only help tackle climate change if low carbon policies were put in place. “Technological advances can reduce the costs of climate policies, but they cannot replace policies,” said Ottmar Edenhofer, chief economist of PIK and co-chair of the IPCC report.