Climate change could soon push Persian Gulf temperatures to lethal extremes

Washington Post, Oct. 26, 2015

The region that gave birth to civilization six millennia ago could soon witness a grim milestone in the history of urban development: the first cities to experience temperatures too extreme for human survival.

A scientific study released Monday predicts that parts of the Persian Gulf could see lethally hot summers by the end of the century, thanks to human-induced global warming that is already contributing to soaring temperatures around the globe.

The report’s authors say coastal cities from Dubai to Iran’s Bandar Abbas could experience summer days that surpass the “human habitability” limit, with heat and humidity so high that even the healthiest people could not withstand more than a few hours outdoors.

Other Middle Eastern cities could approach the lethal threshold, including the Saudi holy city of Mecca, a destination for millions of Muslim pilgrims every year, according to the report in the peer-reviewed journal Nature Climate Change.

Scientists have long maintained that parts of the planet could experience extreme temperatures if global warming continues at current rates. But the suggestion that major world metropolises could cross the “habitability” threshold in the 21st Century surprised some climate experts.

“The threats to human health may be much more severe than previously thought, and may occur in the current century,” Christoph Schaer, a physicist and climate modeler at the Institute for Atmospheric and Climate Science in Zurich, Switzerland, said in a commentary on the study’s conclusions.

The Nature study used high-resolution climate models of the Persian Gulf to examine different scenarios for climate change over the coming decades. The authors, a pair of scientists from Massachusetts Institute of Technology and Loyola Marymount University, focused on a key heat measurement known as the “wet-bulb temperature,” which includes humidity and evaporation rates, averaged over several hours. A wet-bulb temperature of 35 degrees C (95 degrees F) is regarded as the survivability limit for healthy people.

“It is an upper limit to adaptability to climate change due to heat stress,” MIT researcher Elfatih Eltahir told reporters at a news conference called to discuss the findings.

The analysis showed that, at current rates of warming, inhabitants of Persian Gulf cities could experience a combination of heat and humidity so high that the human body is no longer capable of shedding the excess heat through perspiration. The worst impacts would be felt in low-lying areas from Iran’s southern coast to the great metropolises of Dubai, Abu Dhabi, Doha and Dhahran, Saudia Arabia.

“Our results expose a regional hotspot where climate change, in the absence of significant mitigation, is likely to severely impact human habitability in the future,” the authors write in the study.

As travelers to the region can attest, the Persian Gulf region is already notorious for oppressive heat, with temperatures regularly surpassing 110 degrees F in the summer and heat-index values that contribute to high rates of heatstroke among outdoor workers.

The study’s authors say the worst impacts could be avoided if the world’s countries can find the will to curb emissions of greenhouse-gas pollution. In any case, urban planners will soon have to plan for major infrastructure changes as temperatures approach the lethal 35-degree threshold.

“Although it may be feasible to adapt indoor activities in the rich oil countries of the region, even the most basic outdoor activities are likely to be severely impacted,” the report stated.

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