Letter: Warmed by contrails

From Farouk Husain

Cirrus-like cloud (2 April, p 16) that originates as aircraft contrails can be expected to have two effects: trapping heat from the ground, and reflecting solar energy back into space. It would help if the model described evaluated the net global warming effect.

London, UK

The editor writes:

Ulrike Burkhardt, whose results we reported, says her model does include both. She emphasised the trapping effect because it is larger.

London, UK