New York (CNN Business) America's liquefied natural gas boom has a climate change problem, according to a report released on Monday.

The US energy industry is scrambling to build dozens of expensive export terminals that can be used to ship cheap natural gas to China and other fast-growing economies that want to move away from coal.

While those investments make sense today, they will likely be derailed in the longer run by a combination of plunging renewable energy costs and rising climate change concerns, according to the Global Energy Monitor, a network of researchers tracking fossil fuel projects.

Those dual forces will make many LNG projects "unprofitable in the long term," putting much of the $1.3 trillion of investments in the sector at risk, the report said.

The problem is that the LNG boom will create harmful methane emissions — a greenhouse gas that is roughly 30 times more harmful than carbon dioxide emissions. Both coal and natural gas produce CO2 emissions, though natural gas creates far less than coal.

If the proposed LNG expansion goes forward, the climate impact would be twice as damaging as the current installed base of coal in the United States, the Global Energy Monitor told CNN Business.

"We know that LNG is not a good answer climate-wise," Ted Nace, founder and director of the Global Energy Monitor, said in an interview. "It might even be pretty foolish financially — for all the reasons that coal turned out to be a bad investment 10 years ago."

Environmental concerns

Nace said that natural gas can no longer credibly be viewed as a bridge fuel between coal and renewables because of methane leaks. These accidental emissions occur during drilling, in the pipelines or during delivery.

He said that's why the United Nations' Intergovernmental Panel on Climate Change has called for reducing natural gas in the coming decades in order to limit global warming to 1.5 degrees Celsius above pre-industrial levels.

"If you have leakage of methane along any step of the way, you can really undermine your case for this being a good solution carbon-wise," said Roman Kramarchuk, head of scenario policy and technology at S&P Global Platts.

More than $500 billion of LNG projects are on the way in the United States as energy companies seek to take advantage of strong demand from Asia.

Kramarchuk said that there are still cases in which natural gas has "clear environmental benefits" as long as it's pushing out coal and being produced and shipped safely.

But renewables have become increasingly competitive on cost with coal and even natural gas.

Pricey new projects on the way

Still, energy companies plan to spend about $507 billion in the United States alone on LNG import and export terminals, according to the Global Energy Monitor report. That's the most in the world and nearly $100 billion above Canada, the next closest country.

ExxonMobil XOM has partnered with Qatar's state oil company on Golden Pass LNG, an export project located in Sabine Pass, Texas. That $10 billion project , which is scheduled for completion in 2024, is expected to eventually be able to export 16 million tons of LNG a year.

t project that's under development. Even Saudi Arabia wants to get a piece of America's LNG boom. In May, state oil company Saudi Aramco announced a mega preliminary agreement to buy five million tons of LNG per year from a Port Arthur, Texas, exporproject that's under development.

NextDecade NEXT Freeport-McMoRan FCX , Exxon andare the top three owners of pre-construction and in-construction LNG terminals, according Global Energy Monitor.

None of those companies responded to a request for comment.

However, the American Petroleum Institute said in a statement that US natural gas and oil production has increased by 50% since 1990, while methane emissions are down 14%.

"The U.S. natural gas and oil industry is already driving emissions to 25-year lows — more than any nation on earth — made possible by the growing use of clean natural gas for power," the API said.

The business group added, "the U.S. and the world can continue that progress, meet record consumer energy demand, and protect the environment by investing in modern natural gas and oil infrastructure, and that includes infrastructure to export LNG."

Some projects lack contracts

Building out LNG infrastructure requires very deep pockets.

The cost of expanding LNG facilities is "enormous — both in dollar terms as well as in time," Stewart Glickman, an analyst at CFRA Research, wrote in a recent report.

Normally LNG projects don't go forward until they receive contractual backing for at least two-thirds of anticipated capacity, Glickman said.

However, the industry is increasingly confident in the long-term future of LNG due to strong expected demand from China and other fast-growing economies.

Glickman counted at least four major projects that have decided to go forward "on-spec," meaning without that long-term contractual backing.

'Freedom gas'

That confidence may also stem from the enthusiastic backing of officials in Washington, DC, who see LNG as both a powerful economic and diplomatic tool.

In May, the US Energy Department announced plans to boost LNG exports through the Freeport LNG project, which is being built off the coast of Texas.

Not only did Energy Department Under Secretary Mark Menezes hail the project for being a "source of clean energy," but he said it's "critical to spreading freedom gas throughout the world."

Not surprisingly, Nace took issue with the "freedom gas" characterization.

"It's a little bit like the roadrunner going off the cliff and continuing to run," said Nace. "These are very strong incumbent industries — and they're not going to go away without a fight."

Tellingly, billionaire Michael Bloomberg has expanded his own fight against climate change to include natural gas. Last month, Bloomberg launched Beyond Carbon , a $500 million investment aimed at not only accelerating coal plant retirements but "working to prevent new construction of gas plants."

Rather than fossil fuels like gas, Nace argued that the long-term growth opportunity will be solar, wind and other alternatives.

"This century will be owned economically by whoever manages to dominate renewables," he said.