More than one billion children are exposed to increasingly severe heat waves, the World Health Organization (WHO) has warned.

1.5 billion children under one experienced a fivefold increase in the number of heat wave days in 2024 compared with the 1986 to 2005 baseline period, jumping from roughly four days per year to a high of over 20, says the health agency. And these periods of high temperature are becoming longer, more frequent and more severe, the WHO warns.

According to the Met Office, this summer was the hottest on record in the UK , with five widespread heatwaves and 40 days where the temperature was above 30 degrees celsius.…