A global surge in natural-gas production thanks to hydraulic fracturing would not slash global greenhouse-gas emissions even though the fuel emits much less carbon dioxide than coal when consumed, according to a new peer-reviewed study in the journal Nature.
The findings from researchers in several nations, using separate computer models of the effects of abundant global supplies, questions the conventional wisdom that natural gas is a "bridge fuel" to a low-carbon energy system.
Natural gas boosters say expanded deployment of natural gas, which is less carbon-intensive than coal and oil, can check rising emissions while carbon-free sources like solar energy achieve greater scale.
But the paper projects that if the North American gas boom spreads globally, "Future CO2 emissions are similar in magnitude with and without abundant gas, as the two emission trajectories continue to rise over time at similar rates."
The paper released Wednesday, which projects the evolution of global energy use through 2050, concludes that large global gas supplies would not only crowd out some coal, but zero-emissions nuclear and renewable energy as well.
"The additional gas supply boosts its deployment, but the substitution of coal is rather limited and it might also substitute low-emission renewables and nuclear, according to our calculations," said Nico Bauer of the Potsdam Institute for Climate Impact Research, a coauthor of the paper.
In addition, the paper concludes that lower prices driven by abundant supply expands total energy use.
"Lower natural gas prices accelerate economic activity, reduce the incentive to invest in energy-saving technologies, and lead to an aggregate expansion of the total energy system: a scale effect," the paper states. It also notes the leakage of the potent greenhouse gas methane from natural-gas development.
However, the paper also includes an important caveat: It does not look at greenhouse-gas reduction policies beyond what's already in effect. Yet it arrives at a time when a number of governments, including the U.S., are expanding efforts to curb emissions through more aggressive deployment of renewables and efficiency measures, and other steps.
"Global deployment of advanced natural gas production technology could double or triple the global natural gas production by 2050, but greenhouse gas emissions will continue to grow in the absence of climate policies that promote lower carbon energy sources," said Haewon McJeon, an economist at the Energy Department's Pacific Northwest National Laboratory and the paper's lead author.