For an affordable climate win, look to the sky

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Original language: English

Original video: For an affordable climate win, look to the sky · Channel: Bill Gates · 02:10 · Watch on YouTube

Topics: Enterprise AI applications, Health and science

Summary

Aviation is difficult to decarbonize because it causes warming both through CO2 from jet fuel and through contrails. Contrails form when aircraft fly through humid air, where particles from jet engines help ice crystals develop into clouds. These human-made cirrus clouds account for half of aviation’s temperature increase. By identifying contrail-forming areas in advance and adjusting flight altitude, airlines can avoid them at modest cost; cooperation could help scale this approach.

Key points

Aviation is one of the hardest parts of the economy to decarbonize.
Jet fuel produces CO2, which can be addressed with battery-powered planes on limited routes and, over time, sustainable aviation fuels.
A second source of aviation warming is contrails, which are clouds rather than emissions.
Contrails form when planes fly through humid air and engine particles help ice crystals develop.
Human-made cirrus clouds account for half of the temperature increase caused by aviation.
Avoiding humid areas of the sky can prevent contrails from forming.
Advance data can help pilots adjust altitude to avoid contrail-forming areas.
The speaker says this approach could eliminate almost 2% of global warming at a very modest cost.
Cooperation and partnerships could help scale the approach.

Chapters

Start	Chapter	Summary
00:00	Aviation’s climate challenge	Aviation causes warming through jet-fuel CO2, which may be reduced with battery-powered planes and sustainable aviation fuels.
00:31	How contrails form	In humid air, particles from jet engines allow ice crystals to form, creating the clouds seen behind planes.
01:06	Avoiding contrail-forming areas	Contrails account for half of aviation’s temperature increase, and pilots can avoid them by changing altitude based on advance data.
01:37	A low-cost opportunity to reduce warming	The speaker describes altitude adjustments as a modest-cost way to eliminate almost 2% of global warming and highlights the potential of cooperation.

Quotes

One of the hardest parts of the economy to decarbonize will be aviation. — 00:00

Those are not emissions; they’re clouds. — 00:31

Those clouds, those human-made cirrus clouds, are half of the temperature increase caused by aviation. — 01:06

for a very modest cost, we can eliminate almost 2% of all global warming. — 01:37

Concepts and entities

aviation, contrails, sustainable aviation fuels, human-made cirrus clouds

Full transcript (original language)

00:00 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,

00:31 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.

01:06 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,

01:37 they can adjust their altitude to avoid those areas. They already do this to steer around thunderclouds 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

02:10 being built around this work. And with the right cooperation, we can scale this out and have a massive impact.