Natural gas, long seen as a cleaner alternative to coal and an important tool in the fight to curb global warming, may be just as damaging to the climate, a new study has concluded, unless companies can virtually eliminate the leaks that plague its use. .

The study found that it would take as little as 0.2 percent of the gas to leak to make natural gas as big a driver of climate change as coal. That’s a tiny margin of error for gas that’s known to leak from drilling rigs, processing plants and the pipes that transport it into power plants or homes and kitchens.

The bottom line: If gas leaks out, even a little bit, “it’s as bad as coal,” said Deborah Gordon, the principal investigator and environmental policy expert at Brown University and at the Rocky Mountain Institute, a nonprofit research organization focused on clean energy. . “It cannot be considered a good bridge or replacement.”

The revised study, which also involved researchers from Harvard and Duke Universities and NASA, is published next week. in the journal Environmental Research Lettersadds to a large body of research that has poked holes in the idea that natural gas is a suitable transition fuel to a future powered entirely by renewables, such as solar and wind.

The findings raise difficult questions about how much more money the world’s nations should invest in gas infrastructure to avoid the worst of global warming. The $370 billion Inflation Reduction Act passed by the US Congress last year, designed to move the country away from fossil fuels and towards renewable energies, includes credits that would apply to some forms of natural gas.

When power companies generate electricity by burning natural gas instead of coal, they emit only about half the amount of planet-warming carbon dioxide. In the United States, the shift from coal to gas, driven by a boom in oil and gas fracking, has helped reduce carbon emissions from power plants. by almost 40 percent since 2005.

But natural gas consists mostly of methane, which is a far more potent planet-warming gas, in the short term, than carbon dioxide when it escapes unburned into the atmosphere. And evidence is mounting that methane is doing just that: leaking from gas systems in far greater quantities than previously thought. Sensors and infrared cameras help visualize large methane leaks from oil and gas infrastructure, and increasingly powerful satellites detect “super-emitting” episodes from space.

The latest study advances that science in several ways. It considered and compared the entire “life cycle” emissions of natural gas and coal, from drilling and mining the fuel to distribution and burning it. The researchers also looked at natural gas and coal in all their energy uses, beyond generating electricity. Gas, in particular, is used widely as an industrial, commercial and residential energy source for fuel, steam, heat and power.

The study also took into account one strange effect of emissions from burning coal: Some of the emissions may actually have a short-term effect that offsets some of the warming.

That’s because, in addition to carbon dioxide, coal emits sulfur dioxide, which forms sulfate aerosols in the atmosphere. These aerosols reflect incoming sunlight back to space, helping to cool the atmosphere.

Sulfur dioxide has other serious problems. It causes serious damage to human health and the environment. And coal-burning power plants are a major source of other toxic forms of air pollution. Past research has suggested that switching from coal to gas is less harmful to public health.

There are other trade-offs to consider. The carbon dioxide abundantly emitted by coal-burning power plants lasts much longer in the atmosphere than methane, which dissipates after a few decades. So focusing on methane flows from gas infrastructure, at the expense of controlling carbon emissions, means the world may mitigate some shorter-term warming, but still faces a dangerous rise in average temperatures many decades into the future. That said, with the consequences of climate change already wreaking havoc around the world, controlling methane would be a way to slow warming more immediately.

Under pressure over its climate footprint, the oil and gas industry said it had made progress in detecting and plugging rogue emissions. Independent monitoring and verification of those claims will be crucial, experts say.

Robert Howarth, an earth systems scientist at Cornell University who raised the alarm about methane leaks more than a decade ago, called the analysis sound.

“Their conclusion is to point out again that natural gas may not be better for the climate at all than coal, especially when viewed through the lens of warming over the next 20 years, which is of course a critical time” to meet climate goals, he said in an email. .

“I hope the political world and the world’s political leaders pay attention to this, because I fear that too many remain too fixated on simply reducing coal, even if it results in more gas consumption,” Dr Howarth said. “What the world requires is to move away from all fossil fuels as quickly as possible, to a 100 percent renewable energy future.”

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