How Bad Is LNG for the Climate, Really?

President Biden’s decision to pause approving liquified natural gas export terminals until it can better study their climate effects — functionally delaying or even outright preventing their construction — got real political, real fast. Almost immediately, West Virginia Senator Joe Manchin called for a hearing on the president’s decision-making.

“If the Administration has the facts to prove that additional LNG export capacity would hurt Americans, they must make that information public and clear,” he said in a statement last week. “But if this pause is just another political ploy to pander to keep-it-in-the-ground climate activists at the expense of American workers, businesses and our allies in need, I will do everything in my power to end this pause immediately.”

While Senator Manchin is not exactly the administration’s biggest fan lately, he’s also asking some pretty interesting questions. One of the animating ideas of the past few months in climate politics has been the argument that LNG (and maybe even pipeline gas) are in fact far worse for the global climate even than coal, which has long been assumed to be the dirtiest, most carbon-intensive fossil fuel around. That view is based on research by Cornell University scientist Robert Howarth and has been expounded by climate advocates and elected officials alike.

But that research has not yet passed through peer review. Even if it had, Howarth’s past research has gotten criticism from other climate scientists for using some idiosyncratic assumptions that yield more dramatic results.

Make no mistake, meeting the goals of the Paris Agreement and holding global warming to 1.5 degrees Celsius over pre-industrial levels requires winding down our use of fossil fuels as quickly as possible. If we meet those goals, the natural gas export terminals delayed by the Biden administration’s decision will likely go dormant well before the end of their expected lifespans. But it’s not the case that in all possible worlds, continuing or even expanding natural gas production and exports would actually be worse for the climate.

The basic physics of coal emissions versus LNG emissions are just part of the equation. When it’s burned, natural gas releases carbon dioxide, the primary source of human-caused climate change, albeit less carbon dioxide than coal. But natural gas is itself mostly methane, CH4, which traps far more heat than CO2 when it leaks from wells, pipelines, and production facilities. (LNG is also much more energy-intensive to extract, produce, and store than regular natural gas, since it has to be cooled to -260 degrees Fahrenheit, sailed across the ocean and then “regasified” and shipped via pipeline on the other side.) While CH4 is more potent than CO2 from a warming perspective, it also breaks down much more quickly in the atmosphere, which means the warming effect doesn’t last as long.

How to think about LNG’s effect on overall emissions, then, largely depends on how much you think each of these factors matters. “Only if we assume high methane leakage rates and a 20-year global warming potential is natural gas worse than coal, and such assumptions are likely unrealistic,” wrote Carnegie Mellon energy systems researcher Paulina Jaramillo in an essay titled, aptly, “Navigating the LNG Dilemma.”

Absolute emissions aren’t even what we should be asking about, Arvind Ravikumar, a professor at the University of Texas and a leading scholar on natural gas and energy policy, told me. “The climate impact of U.S. LNG depends on what it replaces in countries — whether those alternatives have more or less emissions than U.S. LNG.”

When the United States stepped in to replace much of the gas the European Union would otherwise buy from Russia with LNG, Ravikumar explained, it likely reduced overall emissions because of lower methane emissions from the U.S. gas industry. Before the invasion of Ukraine, Russia supplied about 155 billion cubic meters of natural gas to Europe; by 2022, that was down to around 80 billion cubic meters. That’s a lot of energy to replace. In that time, the U.S. more than doubled its LNG exports to Europe, which has guaranteed demand of at least 50 billion cubic meters from the U.S. through 2030.

Had the U.S. not ramped up its LNG exports, boosters argue, these countries might not have had a viable alternative and might have turned to coal, instead. But that won’t be the case in every single possible future scenario. “There’s no right answer,” Ravikumar told me. “It depends on who buys, what time frame, which country, and how are they using LNG.”

There’s at least one clear case study of the coal-to-gas switch working to lower emissions: the United States itself.

In 2007, the U.S. was consuming just over 1 billion tons of coal for electricity; by 2016 that had declined to 679 million, and by 2022 to just under 500 million — in other words, by more than half. In that same time, natural gas use for electricity grew from 7 trillion cubic feet in 2007 to 10 trillion cubic feet in 2016 to 12 trillion cubic feet in 2022.

U.S. greenhouse gas emissions have dropped more than 15% since 2007 to even below their 1992 levels, according to the Environmental Protection Agency and the Rhodium Group. The drop in emissions has been going on since 2010, which the EPA attributes, in part, to "the growing use of natural gas and renewables to generate electricity in place of more carbon-intensive fuels.”

As climatologist Zeke Hausfather put it in an earlier commentary on an earlier Howarth paper, “While it isn’t responsible for the majority of emissions reductions, natural gas replacing coal is the largest single driver.”

Much of the conceptual infrastructure on which climate policy operates relies on estimating what the world will be like in the future — not just figuring out the effects of different levels of greenhouse gas concentrations in the atmosphere, but also figuring out different likely pathways for the evolution of those emissions over time.

This works in both directions — asking how specific projects either reduce or lower emissions, and asking about what an energy system would look like in a world where emissions have been reduced enough to avoid certain levels of temperature increases. And that’s really where the rubber meets the road.

In a scenario where the world hits its Paris Agreement goals, there would not be the coal-to-gas switching envisioned by LNG advocates precisely because there would be very little coal still being used to generate electricity. The fear, then, is that LNG terminals would either become stranded assets, capital investments that wind up becoming liabilities; or that, once they’re in operation, the companies behind them would use their political and economic leverage — not to mention just the power of inertia — to keep enough natural gas in the global energy system to be profitable.

“Either you’re building and planning to shut it down early,” Hausfather told me, “or you’re building something that’s going to be inconsistent with the world we’re aiming to have under our climate targets.”

In a Paris-compliant world, almost 90% of the world’s coal reserves and over half of the natural gas and oil reserves will stay in the ground, according to researchers from University College London. They estimate that in order to meet the Paris targets, gas production would “see rapid decline” from 2020 to 2050 and would be eliminated as a fuel for electricity generation by 2040, with accompanying “low utilization rates of infrastructure, and limited prospect for future additional liquefaction capacity” for exports.

In other words, in a world that comes in under 1.5 degrees of warming, the emissions reductions from coal-to-gas switching peter out after 2035; with 2 degrees of warming it’s around 2040 to 2045 — in any case, beyond the planned life of the export terminals that the Biden administration’s decision affects.

But how much LNG export capacity the United States builds up in the next decade is only a tiny part of the overall emissions picture now, in 2035, or in 2050. “This is the issue with regulating at a project level in general,” energy consultant Sean Smillie told me. “The decision of any given project in the scheme of global emissions is small. For me, that points to the fact that we’re trying to regulate climate change — which is a systemic issue — at the project level, and that’s a very hard thing to do.”

The biggest question is just how energy systems overseas evolve — and what role LNG exports play in that determination. The European Union is about to decide whether to reduce its net collective emissions 90% from 1990 levels by 2040, on their way to zero by 2050, which would signal a sharp reduction in demand coming from that part of the world. Meanwhile, for U.S. LNG export projects currently in the permitting pipeline, Asian countries are contracted to receive a much bigger share, according to a Public Citizen analysis. Bloombergreports that those buyers have started looking elsewhere — including to Russia.

But what if we don’t hit our Paris Agreement targets, as the United Nations and Bill Gates agree we’re increasingly unlikely to do? What if developing countries prioritize cheap, available energy (like India’s growing coal production) over climate goals? In that case, Ravikumar argues, then LNG export capacity turns from a potential “stranded asset” into an insurance policy.

“The way to think about LNG in the longer term is the insurance against a 3 [degrees of warming] world,” Ravikumar told me. If we fail at taking quick action to change our systems from carbon-polluting to zero-carbon energy, we might still be doing some coal-to-gas switching by 2050.

“It’s hard to say for certain that we will or not need the LNG export terminals by 2050 and 2060,” Elan Sykes, an energy policy analyst at the Progressive Policy Institute and an opponent of the Biden administration’s decision, told me. “Absent aggressive foreign policy measures [like] a Green Marshall Plan for worldwide clean energy, it’s hard to imagine a world where LNG doesn’t provide” some value, whether from continuing to help reduce emissions or simply maintaining a reliable supply of energy, he said.

Modelers are good at figuring out what the energy mix of a 1.5, 2, or 3-degree world would look like. They’re less good at predicting how that energy mix will evolve over time in the world we actually live in — and it’s in that world that the Biden administration will have to decide whether more LNG exports will serve the public interest.

The job isn’t just to make decisions for an ideal world. As Hausfather told me, it’s “aiming at the best versus mitigating the worst.”

With reporting by Emily Pontecorvo.