Every jet made by Boeing last year will produce an average of 1 million tonnes of carbon dioxide over its lifespan of 20 years or more.
That's according to a new report by the planemaker.
Boeing is the latest firm to disclose data on the emissions produced by the use of its products.
And the numbers shed light on just how big a challenge air travel faces in reducing its climate impact.
In all, the jets delivered by Boeing and European rival Airbus last year will generate emissions equivalent to 600 million tonnes over their lifetimes.
That figure would have been much higher, had it not been for a slump in deliveries due to the global health crisis.
Earlier in the year, Airbus claimed slightly lower emissions for its planes, but experts said the difference may just be down to different assumptions made when doing the calculations.
Now the pressure is on to find solutions.
Boeing says its jets will fly on 100% sustainable fuels by 2030, which will help cut emissions.
Aerospace firms around the world are also researching other technologies, including electric power.
But environmentalists say none of that will be enough.
They say only solution will be to limit flying.