Climate Cult Is Worried About Contrails (Again)

They want to reduce them

Fewer contrails would be good for the climate

Good news on global warming is thin on the ground. But there may be some up in the air. Operation Blue Skies, announced on August 18th, is a scientific study being undertaken by Britain’s air-traffic-control service, NATS, and various organisations where people study the effects on climate of the streaks of cloud created by aircraft—known as contrails.

Over the next two winters the consortium aims to see if it is possible to reduce the number of persistent contrails—the class with the largest such effects—over a swathe of the North Atlantic, thereby measurably reducing the climate impact of civil aviation. If this experiment works, a worldwide application of the same techniques might cut the climate effects of air travel by as much as half.

On a sunny day the wispy cirrus clouds into which some contrails are transformed can look as if they might be cooling the planet in the manner of a delicate parasol. And some contrails do indeed cool things down beneath them a bit. But they also warm things up by trapping some of the upwelling infrared radiation that would otherwise escape into space. On average, that warming effect, found in all contrails (and the cirrus clouds they turn into), handsomely outweighs the cooling provided by some. In the climate scheme of things, contrails are a liability.

Happily, it appears that much harm can be avoided by small changes to flight paths. Persistent contrails appear only in what are known as “ice-supersaturated regions” (ISSRs). Often planes can avoid such regions just by flying a little bit lower. The purpose of Operation Blue Skies is to find out how well the presence of ISSRs can be predicted, how effective such little shifts in altitude can be in avoiding persistent contrails, and how easily and safely the changes in flight path needed to bring them about can be integrated into routines for airlines and air-traffic control.

Of course, what the cult really wants is to ban the peasants from flying at all

If contrail-avoidance turns out to be as useful as it looks, it would be much simpler to simply have air-traffic controllers assign routes that limit persistent contrails when it is possible and safe to do so. If some airlines choose to avoid the affected routes, others will surely be happy to take their place. And if such a scheme were also to show the benefits of innovations in air-traffic control (quite a few have been suggested) the industry would end up better off, as well as less polluting.

Which would require political commissars, er, climate cult scientists approving the routes.