According to its researchers in the US, the international study paints an “even grimmer” picture of a global nuclear war’s aftermath than previous analyses.

The research team used newly developed computer climate modelling techniques to learn more about the effects of a hypothetical nuclear exchange, including complex chemical interactions in the stratosphere that influence the amounts of ultraviolet (UV) radiation that reach the planet’s surface.

“Besides all the fatalities that would happen almost immediately, the climate effects and the UV effects would be widespread,” said Charles Bardeen, a scientist at the National Center for Atmospheric Research (NCAR). “These aren’t local to where the war occurs. They’re global, so they would affect all of us.”

Bardeen and his team found that smoke from a global nuclear war would destroy much of the ozone layer over a 15-year period, with the ozone loss peaking at an average of about 75 per cent worldwide. Even...