A new study finds the world could still avoid 1.5 ˚C of warming, achieving the aim of the landmark Paris climate accord. The bad news is we almost certainly won’t.

If we immediately began phasing out fossil-fuel infrastructure at the end of its lifetime—retiring all coal plants, cars, planes, and factories—we’d have a 64% chance of holding peak global warming below 1.5 ˚C, according to a paper by researchers at Oxford, the University of Leeds, and other institutions published January 15 in Nature Communications. In that scenario, the world would replace all those facilities and machines with zero-carbon alternatives, like solar plants and electric vehicles.

In effect, the study highlights the consequences of our societal choices from this point forward, by taking into account the useful life of our fossil-fuel-burning assets. If we wait until 2030 to stop adding more, our odds of exceeding 1.5 ˚C significantly increase, even if we then start forcing vehicles and plants into early retirement.

The paper sidesteps the question of whether it’s practically feasible to halt all new development of fossil-fuel infrastructure, though it almost certainly is not. Instead, there’s every indication the world is going to continue building carbon-spewing power stations, vehicles and other machines for many years to come.

Chinese companies are planning or constructing hundreds of coal plants around the world, according to the New York Times. India continues to invest billions in new coal-fired facilities. And electric vehicles represent only a tiny fraction of automobile sales in the United States, where the real demand is still for gas-guzzling SUVs and trucks.

An added challenge is that there are big greenhouse-gas-emitting sectors of the economy where we don’t have readily available clean alternatives, including aviation, agriculture, cement, and steel.

So while the study finds that the world could, theoretically, avoid 1.5 ˚C of warming, what it really underscores is the growing likelihood that we’re going to sail past it. The scenario it describes would be difficult if not impossible to achieve under our current political, economic, and technical realities. (Notably, other researchers have found that existing energy infrastructure alone may already commit the world to catastrophic levels of warming.)

But even if we’re going to miss the 1.5 , 2, or even 3 ˚C threshold, the larger message remains: the faster we shift away from fossil fuels, the more we can limit the damage and dangers to come.