Oliver Morton
speaker
275 appearances
4 recordings
1 series
first heard Jul 2026
last heard 7 Sep
Oliver Morton’s voice in public audio — every appearance, attributed to the second.
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recordings per month · last 12 monthsRecordings per month over the last 12 months — 4 in all, peaking in Aug 2026 with 2.
Appearances
For about 30 years, people have been aware that the contrails that stretch out behind planes when they fly through the upper atmosphere have a warming effect on the Earth.
So if you could make fewer of them, then you could, to some extent, cool the Earth down a bit.
Various people have tried this out in small-scale ways with specific airlines or in specific places, but now a large trial is starting over the North Atlantic, which is a very sensitive area for contrails and almost the perfect place to do it.
It's called Operation Blue Skies.
Well, contrails, like all clouds, they give and they take away.
They reflect a bit of sunlight out to space, so they're cooling.
But they also trap heat trying to get out of the Earth and infrared radiation and re-emit it downwards.
So they have two effects.
And although some contrails sometimes may be mainly cooling, on average, contrails are warming.
And they're particularly warming, of course, at night because there's no sunlight to reflect and you just get the warming effect.
And depending on how you calculate it, the warming effects of contrails are a bit less than or maybe the same as the warming effect of the carbon dioxide that's emitted by planes in the first place.
So in terms of the climate impacts of aviation, it's really significant.
Not just the wispy little trails, the clouds that the wispy little trails turn into.
But yes, it is striking.
Now, I think we should normally say up to 50% because the error bars on the amount of warming that you get from contrails are quite large.
To get up to 50%, you need to think your estimate for the contrails is a bit low and your estimate for the fuel may be a bit high.
Half is quite possible.
A third, I think you could probably take to the bank.
They are to some extent a byproduct of flying, but the ones that really matter are the ones that last and then persist.
You'll have seen them in the skies as they spread out and become broader, pale clouds.
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