With business continuing as usual, climate pollution from aviation could nearly triple by 2050 as demand for air travel grows, according to a new study published yesterday in the journal Nature Sustainability. It would cost up to $1 trillion to try to remove enough of that pollution from the atmosphere to meet global climate goals — an untenable situation.

To put that enormous cost into context, the global airline industry only netted $26.4 billion in profits in 2019 before the covid pandemic curbed travel. And even if airlines can pay to remove all their emissions from the atmosphere, that’s still not guaranteed to slow climate change. While carbon offsets — paying to cancel out your climate pollution through green projects like planting trees — are popular, they’re wildly unreliable.

A surefire way to cut down that pollution is to keep the aviation sector from expanding as rapidly as it did for years before the covid pandemic. Keeping growth in air travel demand nearly flat through 2050 could avoid more than 60 percent of those business-as-usual emissions, according to the new study. Another 27 percent of emissions could be prevented through improved energy efficiency. And deeper cuts will require developing less-polluting fuels.

The authors of the new study mapped out ways for aviation to reach net-zero carbon dioxide emissions, a point when the industry no longer pumps out more CO2 pollution than it can take out of the atmosphere. Back in 2021, the International Air Transport Association set a goal of reaching net-zero emissions globally by 2050. It’s a research-backed timeline that falls in line with global climate goals under the Paris agreement.

To be sure, even the most ambitious pathway to net zero — with demand for air travel nearly flatlining at just 1 percent growth each year — includes some carbon removal. After all, the aviation sector still has to compensate for other plane emissions outside of CO2 that contribute to global warming — for example, the thin lines of clouds that form in the wake of a plane, called contrails, that trap heat.

There are new efforts to build out big CO2-sucking plants that can filter the greenhouse gas out of the air, but this technology is still prohibitively expensive and unproven at scale. Electric planes and hydrogen jets are in a similar conundrum; they won’t get off the ground in time to make the kind of pollution cuts that are needed now.

In other words, there’s no quick techno-fix to aviation’s pollution problem. Climate-wise, flight is considered one of the hardest sectors to clean up. But for such a complex problem, there’s at least one straightforward solution: flying less. Just limiting demand to 1 percent growth each year instead of the 4 percent projected by the industry makes a huge difference, the new research shows.

And that task could fall squarely on “super emitters” — the 1 percent of the population that’s been found to generate half the world’s CO2 emissions from commercial aviation. Maybe they can cough up the $1 trillion it would cost to bet on carbon removal to erase the consequences of business as usual. But if the poor track record we’ve seen so far with carbon offsets is any indication, it’d be a big gamble.