but contrails are not made of soot, where I define soot as dark unburned carbon, contrails actual are made of water. There is also a highly likely chance I am being to literal and the word choice of soot was a bit of poetic license on the part of the author.

As a bonus consideration it might be better if they were made of soot, it would be ugly but water vapor is a tremendous greenhouse gas, several times as potent as CO2, soot blocking the sun might have more of a neutral effect, And related, we worked hard to get sulfur out of our fuels but sulfur dioxide turns out to be a negative greenhouse gas, it has a net cooling effect, I am not saying we should deliberately add sulfur back in, the downsides are too great, but it is an interesting bit of irony.

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bird0861 2 days ago | parent [-]

The water is actually ice crystals and the ice crystals form around the soot.

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wolttam 2 days ago | parent [-]

There is also an immense amount of water vapour being produced by the combustion of a hydrocarbon.

	▲	counters 2 days ago \| parent [-]
		Sure, but water vapor doesn't spontaneously transition to a liquid and accrete onto surfaces - there needs to be a super-saturation of water vapor, and given the temperatures of jet exhaust, that's not trivial to achieve. However, the super-saturation needed for water vapor to deposit onto surfaces as ice is much lower, hence the preference for ice crystal nucleation.