By 2050, virtually every child on earth – over 2 billion children – is forecast to face more frequent heatwaves, regardless of whether the world achieves a ‘low greenhouse gas emission scenario’ with an estimated 1.7 degrees of warming in 2050 or a ‘very high greenhouse gas emission scenario’ with an estimated 2.4 degrees of warming in 2050. These findings underscore the urgent need to adapt the services children rely on as unavoidable impacts of global heating unfold.