Do airplane contrails cool or heat the earth? A Limerick.

The contrails we see in the sky

are bad they all say. I ask: Why?

For the contrails reflect

the sun’s rays. That effect

cools more, kiss the greenhouse goodbye.

Are airplane contrails contributing to the warming the earth?

Contrails are the condensation clouds that are formed under certain conditions,

and at certain altitudes, from jet engines.

It is true that the contrails act as another cloud, trapping the greenhouse gases under it. But that is not all there is. It matters at what time of day or night the contrails are formed. Pilots, as a rule prefer to fly by night, but people prefer to be flown by day, so most flights occur during daytime.

This is a fantastic 24 hour visualization of all flights. Most notable is that the vast majority of airplane flights occur during daytime, and occur over continental United States and Western Europe.

Contrails formed during daytime reflect incoming solar radiation back into space, and this reflection cools the surface of the earth much more than the trapping of greenhouse heat, which occurs both during day and night.

So, contrary to popular belief, contrails cool the earth.