Recent research suggests that exposure to dangerous temperatures in urban areas has increased by 200% since the mid 1980s. As a result of global warming and the urban heat island effect, extreme heat now affects almost two billion urban residents, far more than had been previously realised.

The study, which is the first to examine in fine detail global trends in extreme heat exposure across urban areas, assessed data covering more than 13,000 settlements. In approximately 50% of these, extreme heat exposure was found to be increasing.

The authors note that such trends place poor and marginalised people in particular at risk, given that they generally face food insecurity, live in urban areas more prone to prolonged periods of extreme heat and have fewer options to mitigate their exposure.