Night flights much worse for global warming

Restrictions on night-time aircraft flights could help in the fight against global warming as well as making life easier for people living near airports.

A study found the condensation trails, or contrails, left by the exhaust of aircraft engines contribute more to global warming during the night than by day. The effect was greater in the winter when nights are longer than during summer. The scientists behind the study, published in Nature, said the results suggest rescheduling flights for the day could help minimise the impact of aviation on climate change.

Contrails are clouds of tiny ice particles that reflect light and heat. They have opposing effects on the Earth's natural greenhouse effect. They tend to trap more heat leaving the ground than they reflect back into space.

But the amount of heat they trap depends on what time of day the contrails are produced because during day the trails reflect more incoming sunlight from space than they trap.