How Avoiding Contrails Can Reduce Aviation's Climate Impact

One of the hardest parts of the economy to decarbonize will be aviation. Aviation creates warming in two ways.

The first is CO2 emitted from the jet fuel that's burned.

To reduce that, battery-powered planes can come in with limited range, and over time we'll develop sustainable aviation fuels, that is plug-in fuels with net zero carbon emissions. But the second part of aviation warming comes not from the fuels, but actually from the contrails. These are the clouds that you'll

sometimes see behind the plane as they fly.

Those are not emissions, they're clouds.

What's going on is that if a plane flies through an area that the humidity, the water saturation of the air in that area is high, then the particles that come out of the jet engine allow ice crystals to form, and that's what you see when you see those long white clouds trailing behind a jet plane.

Those clouds, those human-made cirrus clouds, are half of the temperature increase caused by aviation, and they really trap the heat that's coming out of the earth.

If the path that the plane takes avoids those parts of the sky where you have lots of water, where you have that humidity, then you avoid forming the contrails. Figuring out in advance where the contrail-forming areas are and bringing data to the pilot, they can adjust their altitude to avoid those areas.

They already do this to steer around thunder clouds or areas with high turbulence. Small changes in altitude, either go below it or to go above it, require the least deviation.

And the airline industry is engaged on this issue.

So it means that for a very modest cost, we can eliminate almost 2% of all global warming.

I mean, it's really unbelievable, and it's also an example of really great partnerships being built around this work.

And with the right cooperation, we can scale this out and have a massive impact.