Extreme heat caused by this year’s “super El Niño” could lead to as many as 451,000 excess deaths worldwide in the six months to February 2027, according to researchers at the University of Chicago’s Climate Impact Lab. The number of extremely hot days is expected to rise by 44%, with Nigeria, Indonesia and Sudan among the countries likely to be worst affected. Researchers warn that the impact could extend well beyond the six-month period studied. Carys Garland reports.