The world already has enough fossil fuel plants and high-emitting industrial facilities, buildings, and cars to drive average global warming above a 1.5°C threshold, according to an article earlier this month in the journal Nature.

“1.5°C carbon budgets allow for no new emitting infrastructure and require substantial changes to the lifetime or operation of already existing energy infrastructure,” write a team of researchers led by Dan Tong of the University of California Irvine.

The study concludes that existing fossil infrastructure “merely needs to continue operating over the course of its expected lifetime, and the world will emit over 650 billion tons of carbon dioxide, more than enough to dash chances of limiting the Earth’s warming to a rise of 1.5°C (or 2.7°F). That’s a level of warming that has become increasingly accepted as a scientific line-in-the-sand,” the Washington Post reports.

“And it gets worse: Proposals and plans are currently afoot for additional coal plants and other infrastructure that would add another nearly 200 billion tons of emissions to that total. Some of these are now actually under construction. In other words, human societies would need not only to cancel all such pending projects but also timeout existing projects early, in order to bring emissions down adequately.”

The Post points to the 41 gigatons of carbon dioxide entering the atmosphere each year, 36 of them from fossil fuel burning and cement production, and compares those totals to the 420- to 580-gigaton carbon budget remaining to produce a 50 to 66% chance of limiting average warming to 1.5°C.

“That amounts to between 10 and 14 years at current emissions, with one year, 2018, already used up and another, 2019, halfway gone,” writes climate specialist Chris Mooney. “What the new study is saying is that existing infrastructure translates into about 16 years of current emissions just on its own, with another roughly five years in the pipeline in the form of currently planned infrastructure.”

While other research on fossil infrastructure has presented a less dire verdict, Mooney adds, “the new study contends that it contains the latest, and most plausible, estimates. Its figures for existing fossil fuel infrastructure are for 2018.”

Study co-author Ken Caldeira of Stanford University’s Carnegie Institution for Science was involved in a similar study a decade ago, and found that existing infrastructure equated to only 1.2°C average warming.

“A decade ago, we found, there’s not enough infrastructure, and now, over the past decade, we have built enough stuff,” he told the Post. “And a lot of that stuff that was built, was built in Asia—the rise of China, and to a lesser extent India and the other southeast Asian countries, [is] the biggest change in direction regarding amount of infrastructure.”

Part of the problem is that those new plants are “younger”, the Post notes, meaning a longer expected operating life before they’re shut down. “And the picture is actually worse than the study suggests, because the research does not include emissions caused by human-led deforestation of tropical forests and other landscapes.”

Elmar Kriegler of Germany’s Potsdam Institute for Climate Impact Research said the new article “shows the huge role that the buildup of coal-fired power plants and heavy industry in China has played over the past 15 years,” driving recent increases in global CO2 emissions and accounting for half of the future emissions associated with new infrastructure. “If this buildup of coal infrastructure is going to repeat itself in other rapidly growing economies, notably India and South East Asia, the world will stand no chance to hold warming to well below 2.0°C.”

At the same time, “whether it is already too late for limiting warming to 1.5°C, as the authors claim in their headline, is too early to say,” Kriegler continued. “As the article points out, this will depend on whether the world can prematurely retire some of the heavy polluting infrastructure that has been put in place.”

The Post notes that some of those early retirements are already taking place, as solar and wind undercut coal and other forms of fossil fuel generation on price. The article also holds out hope for carbon capture technology to remove CO2 from existing fossil infrastructure.

“To me, the optimistic take on it is that most of the emissions associated with the higher warming scenarios come from infrastructure that’s yet to be built,” Caldeira said. “So avoiding those outcomes is still within our control, and it’s largely a political and social decision.”

But he cautioned: “I’m just hoping that nobody will be writing a decade in the future, ‘Oh, we built enough infrastructure to go through 2.0°C, but we can still avoid 2.5.’