‘Deadly heat waves could hit one-third of African city-dwellers’

A scientific research assessment of a range of possible scenarios regarding the rate of climate change and socio-economic development in 173 African cities for the years 2030, 2060 and 2090 showed that a third of African city-dwellers could be affected by deadly heat waves in 2090.

The results, published yesterday in the journal, Earth’s Future, said at least 217 billion would be exposed every day to a minimum temperature of 40.6°C or that every African city would experience this heat for four months of the year by 2090.

The researchers from the University of Geneva (UNIGE), Switzerland, in collaboration with the University of Twente (The Netherlands) and the European Union (EU) Joint Research Centre in Ispra (Italy), blamed the increasing exposure to extreme temperatures on a very steep population increase, an explosion in urbanisation and a climate badly disturbed by a continuous increase in carbon dioxide (CO2).

However, until now, several studies have shown that prolonged exposure to extreme heat can cause heat exhaustion, heat cramps, heat stroke and death, as well as exacerbate pre-existing chronic conditions, such as various respiratory, cerebral and cardiovascular diseases.

The researchers said if every inhabitant in the 173 cities studied were exposed every day of the year in 2090, the figure would rise to 647 billion. “We see that the worst scenario for 2090 affects 217 billion people – that’s a third of Africa’s urban population potentially exposed on a daily basis!” the UNIGE researcher said.

A researcher at UNIGE’s Institute for Environmental Sciences (ISE), Guillaume Rohat, said: “We consider the critical threshold to be 40.6°C in apparent temperature, taking humidity into account. In fact, high outdoor humidity levels disrupt our ability to thermo-regulate, with potentially fatal consequences.”

Also, the scientists from UNIGE, the University of Twente and the EU Joint Research Centre based their research on scientific climate projections and future urban demographics (rather than on current demographic data) to calculate the risk in the years ahead – which was in itself a first.

Regardless of which hypothesis is selected, the study makes it clear that exposure to extreme temperatures is going to rise sharply. But it also shows that if we act quickly, the increase can be at least partially curbed.

“That is why we are currently in contact with several cities that we studied,” said Rohat.