The basic conclusion here is, in some ways, striking. We've already built a system that will propel the planet into the dangerous terrain that scientists have warned for decades we must avoid. This means that building lots of renewables and adding lots of green jobs, the focus of much of the policy debate over climate, isn’t going to get the job done.

We now have to ask a much harder societal question: How do we begin forcing major and expensive portions of existing energy infrastructure to shut down years, if not decades, before the end of its useful economic life?

Power plants can cost billions of dollars and operate for half a century. Yet the study notes that the average age of coal plants in China and India—two of the major drivers of the increase in “committed emissions” since the earlier paper—­­­­­­­is about 11 and 12 years, respectively.

Other options for reducing climate impacts could include retrofitting existing energy infrastructure with systems that capture climate emissions, or offsetting emissions with tools that can remove carbon dioxide from the atmosphere. But both of those are expensive as well.

Early retirements or pricey retrofits will almost certainly not happen without strict government mandates, significant carbon prices, or technological breakthroughs that either directly force the hands of energy companies or alter the economics enough to nudge them along.

“The industry has trillions of dollars of assets that will not go easy into that good night, as it were, so we’re going to have to figure out a way to hasten that,” says Steven Davis, an associate professor at the University of California, Irvine.

Davis worked on both papers, along with Ken Caldeira, a senior scientist at the Carnegie Institution. The lead author of the new study is Dan Tong, a postdoc in Davis’s research group at UC Irvine.

The scientists conducted the study by pulling together global data sets tracking major carbon dioxide sources like power plants, vehicles, industrial boilers, and residential appliances such as furnaces and stoves. Together, they’d pump out about 660 billion additional metric tons of greenhouse gases from this point forward, well above the 580 billion tons that mark the top end of the estimated range for limiting warming to 1.5 ˚C.

(The study doesn’t address non-energy greenhouse-gas sources, which include potent emissions from things like fertilizer and livestock. But those sources are already factored into the level of energy system emissions that will reach or exceed the UN climate panel’s “carbon budgets” for particular temperature levels, which were employed in the study.)

Meanwhile, the world is busy building more energy infrastructure. Power facilities already in the pipeline—“planned, permitted, or under construction”—would emit nearly 200 billion metric tons of carbon dioxide, the researchers found. Most of those impending facilities are in China, India, and the rest of the developing world.

Emissions from existing systems plus these planned plants would add up to about 850 billion tons, closing in on the carbon budget for 2 ˚C, which runs between 1,170 and 1,500 billion tons.

The tiny bright spot here is that it seems we haven’t already built or planned enough energy infrastructure to exceed that more dangerous warming threshold (unless these systems operate at higher rates or for longer durations than they have in the past). But there’s little indication that nations, particularly in the developing world, will suddenly stop building fossil-fuel plants after completing what’s in the pipeline.