All the power plants, vehicles and other fossil fuel-burning infrastructure operating today will lock the world into 1.5 degrees Celsius of global warming, exceeding the Paris climate agreement goals, unless the biggest polluters are shut down early or are retrofitted to capture their carbon emissions, a new study shows.

And that's just the infrastructure already built. When the researchers factored in the future emissions of coal- and gas-fired power plants that are currently planned or under construction, they found the total lifetime emissions would shoot past 1.5°C (2.7°F) warming and put the world on pace to burn about two-thirds of the remaining carbon budget for staying under 2°C (3.6°F) warming compared to pre-industrial times.

The findings imply profound changes for the planet and many of its inhabitants in this century. As global temperatures rise, heat waves continue to intensify, extreme precipitation increases, and an additional 10 million people face greater risks from sea level rise in just the half degree between 1.5°C and 2°C, among other threats, the Intergovernmental Panel on Climate Change (IPCC) wrote last fall.

"We have already built enough to take us over 1.5," said Ken Caldeira, an atmospheric scientist at the Carnegie Institution for Science and a co-author of the study. "For these 1.5 scenarios you would either need to retire CO2 emitting infrastructure early or have carbon dioxide removal strategies which are generally thought to be expensive."

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Nine years ago, Caldeira co-authored a similar study that found the planet had already locked in about 496 gigatonnes of carbon dioxide with existing infrastructure, emissions that would result in about 1.3°C of warming above pre-industrial levels.

Since then, China and India have been on power plant construction sprees. The average age of their coal-fired power plants are 11 and 12 years, respectively, compared to nearly 40 years in the United States, according to the new study. The historical average lifespan of a power plant, and the age used for calculations in the study, is about 40 years.

"What we see now is a lot more carbon-emitting infrastructure than we saw a decade ago," Caldeira said. "The trajectory is not going to where we would like it to go to."

Future Emissions Likely to Be Even Higher

The new study found that existing energy infrastructure would emit about 658 gigatons of carbon dioxide over the rest of its expected lifetime, and that the future fossil fuel power plants that are currently planned would boost that to about 846 gigatons. The IPCC has determined that to have a 50 percent chance of keeping surface air temperature warming under 1.5°C, the world would need to limit emissions from all human activities to about 580 gigatons of carbon dioxide.

The future emissions are likely even higher than the study estimates. It does not take into account future emissions from other sectors including shipping, aviation and heavy industry that will be hard to wean off of fossil fuels. Nor does it account for emissions related to fossil fuels extraction and pipelines or non-energy emissions such as from agriculture.

Emissions from yet-to-be-built ships, planes, factories and other fossil fuel-powered infrastructure will likely outweigh emissions saved from the early retirement of existing fossil fuel power plants, said Gunnar Luderer, head of the Energy Systems Group at the Potsdam Institute for Climate Impact Research in Germany, who reviewed the study.

For the new study, the researchers used detailed datasets of fossil fuel-burning energy infrastructure operating in 2018 or planned. They found some progress, including "substantial" cancellations of proposed fossil fuel power plants in the past two years, which cut the expected emissions from future power plants by as much as half from studies conducted just a few years earlier.

In the U.S., utilities have been announcing plans to shut down coal-fired power plants and add more renewable energy as the costs of solar and wind power generation fall, but other types of fossil fuel infrastructure have been expanding—particularly natural gas drilling and pipelines to carry oil and gas, both for domestic use and for export to other countries. On June 20, for example, Energy Transfer LP announced it planned to nearly double the capacity of the Dakota Access oil pipeline, a project that was highly contested over both climate and environmental concerns when it was approved in 2017.

No Time for Debate or Delay

Other studies have used different methods to estimate emissions growth.

One study, published in Nature Communications in January, determined there was a 64 percent chance that existing energy infrastructure wouldn't commit the planet to passing 1.5°C warming, provided construction of additional fossil fuel energy infrastructure stopped immediately and other measures were taken to dramatically reduce emissions from all other sectors of the economy.

Such measures would have to happen in the immediate future, said Joeri Rogelj, a lecturer at the Grantham Institute at Imperial College London and a co-author of the January study.

"Both studies are really clear," Rogelj said. "If we wait another 5 to 10 years with being serious about emissions reductions and addressing climate change then indeed we will have no discussion anymore whether we can still make it to 1.5. It will be very clear and obvious that we will run past it."