Worthy effort I’m sure, and something worth considering, something must be done etc… but when you read:
“Prof Hayward says the next challenge is for airlines to work out how altitude changes of a "few thousand feet" can be made mid-flight to avoid contrails while also not disrupting passengers' comfort. A pilot would need to spot these in "sufficient time for an aircraft to adapt gracefully", he adds.”
You realise that this is yet another area where some of the researchers, ever willing to comment, have perhaps had little if any exposure to operational flying.
Neve mind upsetting the G&T, I think more of a challenge might be how these “few thousand feet” altitude changes are going to be facilitated for presumably multiple aircraft in busy RVSM airspace…
(BTW and as a FWIW umpteen decades back some Met forecasts included/details the minimum contrail/ “Mintra” levels/altitudes, I guess now there’s the ability to do it much more accurately than in days of old).