Nineteen of the twenty hottest years on record have occurred since 2001, not including 2020 which is on track to top the list. Research has found that mean annual temperatures above 29°C, currently found in 0.8% of the world and too hot to live in, could affect up to one third of the world’s population by 2070. Saudi Arabia’s already intolerable summers could become prolonged by several months each year as a result.

This case study is based on the paper “Future of the human niche”, published in PNAS by Xu, Chi et al. (2020). 

As a species, we have historically avoided living outside of mean annual temperatures (MATs) between ∼8°C to 20°C. MATs above 29°C, found only in parts of the Sahara and Saudi Arabia, are generally considered too hot to live in but there are always exceptions. The hottest inhabited place on Earth today is the city of Mecca in Saudi Arabia, whose MAT stands at 30.5°C, and stays above a 34°C average between May and September. It receives an average of 2 million Muslim pilgrims each year, densely packed under scorching temperatures that can reach 54°C. 

With the exception of its western coast, the Kingdom of Saudi Arabia has a desert climate with extreme heat during the day, replaced with low temperatures at night and very little rainfall. Lower humidity makes the heat more bearable to a degree, but remaining outdoors for more than a few minutes is dangerous even for a healthy, fit individual. 

Summer peak temperatures are basically as bad as it gets, but many places get much needed relief the rest of the year. The Saudi government is known to relocate from the capital of Riyadh (MAT 28°C) in summer to cooler regions on the west coast. Essentially, higher MATs in Saudi Arabia do not indicate higher peak temperatures, but rather longer periods of extreme heat. A recent study by Xu et al (2020) shows that over half the country could end up having to deal with much longer summers. 

Saudi Arabia summers 2070

The Saudis haven’t “grown used to” these conditions and simply managed, but rather have developed the necessary infrastructure to counter the problem. Most people can move between home and work without ever leaving an air-conditioned space. Ironically, emissions for such extensive AC networks are adding to the problem, although the country is considering more efficient systems that could significantly reduce environmental impacts.

There is still a relatively large proportion of Saudi Arabians living in rural areas, where heat mitigation comes through smart building and street design, or traditionally vetted nomadic strategies. These people represent a more vulnerable segment because AC may not be accessible to all of them. 

Saudi Arabia summer heat vulnerable population

Proportion of Saudi Arabians exposed to MATs above 29°C, with the portion of those highly vulnerable due to decreased access to heat mitigation. Population numbers based on UN predictions for population growth by 2070.

Of course, it is likely that the Saudi government will implement AC for all of its inhabitants by 2070, thus fixing the problem. But picture a world in which you spend 5-6 months entirely indoors because your country has become Mars on Earth. It is also reasonable to imagine that the agriculture and fishing industries will take a severe hit, if not disappear entirely. This would leave the Kingdom dependent on external aid, while it continues to warm our atmosphere with its indispensable AC networks. Things will get hairy quite fast if we reach this point, so let’s make it our responsibility to learn, educate those around us and act where we can while there is still time. 

This article was written by Owen Mulhern. 

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