Climate change: The world now has twice as many days with temperatures above 50 degrees Celsius.

Since the 1980s, the number of extremely hot days per year when the temperature exceeds 50 degrees Celsius has more than doubled.

They also now occurs in more regions of the world than previously, creating tremendous challenges to human health and to how we live.

Since 1980, the overall number of days with temperatures above 50 degrees Celsius has climbed in each decade. Temperatures reached 50 degrees Celsius on average 14 days per year between 1980 and 2009.

Between 2010 and 2019, the number increased to 26 days per year.

Temperatures above 45 degrees Celsius or higher happened an extra two weeks per year on average throughout the same time period.

"The increase is entirely due to the use of fossil fuels," says Dr Friederike Otto, associate director of the University of Oxford's Environmental Change Institute.