Within this century, parts of the Persian Gulf region could be hit with unprecedented events of deadly heat as a result of climate change, according to a study of high-resolution climate models.

The research reveals details of a business-as-usual scenario for greenhouse gas emissions, but also shows that curbing emissions could forestall these deadly temperature extremes.

The study, published today in the journal Nature Climate Change, was carried out by Elfatih Eltahir, a professor of civil and environmental engineering at MIT, and Jeremy Pal PhD ’01 at Loyola Marymount University. They conclude that conditions in the Persian Gulf region, including its shallow water and intense sun, make it “a specific regional hotspot where climate change, in absence of significant mitigation, is likely to severely impact human habitability in the future.”

Running high-resolution versions of standard climate models, Eltahir and Pal found that many major cities in the region could exceed a tipping point for human survival, even in shaded and well-ventilated spaces. Eltahir says this threshold “has, as far as we know … never been reported for any location on Earth.”

That tipping point involves a measurement called the “wet-bulb temperature” that combines temperature and humidity, reflecting conditions the human body could maintain without artificial cooling. That threshold for survival for more than six unprotected hours is 35 degrees Celsius, or about 95 degrees Fahrenheit, according to recently published research. (The equivalent number in the National Weather Service’s more commonly used “heat index” would be about 165 F.)

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See how climate change could bring deadly heat to Persian Gulf

Video: Melanie Gonick/MIT (additional images courtesy of Eltahir Group/MIT)

This limit was almost reached this summer, at the end of an extreme, weeklong heat wave in the region: On July 31, the wet-bulb temperature in Bandahr Mashrahr, Iran, hit 34.6 C — just a fraction below the threshold, for an hour or less.

But the severe danger to human health and life occurs when such temperatures are sustained for several hours, Eltahir says — which the models show would occur several times in a 30-year period toward the end of the century under the business-as-usual scenario used as a benchmark by the Intergovernmental Panel on Climate Change.

The Persian Gulf region is especially vulnerable, the researchers say, because of a combination of low elevations, clear sky, water body that increases heat absorption, and the shallowness of the Persian Gulf itself, which produces high water temperatures that lead to strong evaporation and very high humidity.

The models show that by the latter part of this century, major cities such as Doha, Qatar, Abu Dhabi, and Dubai in the United Arab Emirates, and Bandar Abbas, Iran, could exceed the 35 C threshold several times over a 30-year period. What’s more, Eltahir says, hot summer conditions that now occur once every 20 days or so “will characterize the usual summer day in the future.”

While the other side of the Arabian Peninsula, adjacent to the Red Sea, would see less extreme heat, the projections show that dangerous extremes are also likely there, reaching wet-bulb temperatures of 32 to 34 C. This could be a particular concern, the authors note, because the annual Hajj, or annual Islamic pilgrimage to Mecca — when as many as 2 million pilgrims take part in rituals that include standing outdoors for a full day of prayer — sometimes occurs during these hot months.

While many in the Persian Gulf’s wealthier states might be able to adapt to new climate extremes, poorer areas, such as Yemen, might be less able to cope with such extremes, the authors say.

Christoph Schaer, a professor of atmospheric and climate science at ETH Zurich who was not involved in this study, provided an independent commentary in the journal, writing that while deadly heat waves have occurred recently in Chicago, Russia, and Europe, in these cases infants and the elderly were most affected. The new study, Schaer writes, “concerns another category of heat waves — one that may be fatal to everybody affected, even to young and fit individuals under shaded and well-ventilated outdoor conditions.”

Schaer writes that “the new study shows that the threats to human health may be much more severe than previously thought, and may materialize already in the current century.” He told MIT News, “I think the study is of great importance, since it indicates where heat waves could get worst if climate change proceeds.”

The research was supported by the Kuwait Foundation for the Advancement of Science.

Unfortunately, the deniers of climate-change will scoff at this, as usual, and think nothing of the impact, nor have a concern for those directly affected.A possible proposal would be to transfer the "deniers" to the Persian Gulf region for a year, and in exchange, let an equal number of Persian Gulf residents go to the US, or to Australia(another site where a bevy of "climate-change deniers" dwell).

There would be an irony to this as the Persian Gulf is also the source of a large portion of the hydrocarbons being used.

The conclusions drawn are completely model-dependant. In many parts of the globe temperatures in the 1930s were as warm or warmer than the "normals" now. In Beirut they were significantly warmer. In Bushehr, Iran the differences are small and not significantly different. The overall temperature of the Red Sea today is the same as it was in the 1870s.

The hydrocarbons have been utilized, globally, by two billion more people than there were just 30 years ago... while "we" added 50 ppm CO2 to the atmosphere. What did we expect to happen? Temperatures in the region are not significantly different than they were in the 1930s, and in some places in the world they are cooler now.

The real irony to this is that mitigation can do nothing meaningful about it. There are now seven billion...all needing energy.

While this may be correct information from a purely 'scientific' point of view, I can testify that years ago, before air conditioning was prevalent in south west Florida, I spent many eight hour days working in full summer sun in the Naples area, with no shade what so ever at any time during the hours from 0700 to 1530.

One day, after a couple of days when we were working in deep ditches connecting storm sewer pipe of five feet diameter, with no breeze at all in the ditches, i took an old mercury and glass type thermometer to work, took it down into the ditch, and watched the mercury burst right though the glass, well above the 140 degree F mark - F being the only scale those days...

Yes, our lead person insisted we drink water at least every half hour, and also insisted we take the tiny salt tablets common at the time... after work, i would frequently swim an hour or two the the balmy gulf, then run on the beach for fun and relaxation.

IMHO, it is better to re think and perhaps re imagine the range of human adaptability than run scare headlines such as this one, before such headlines contribute even more to all of us living our lives in boxes of climate perfection powered by petro fuels, or even solar (that has it's own ''lifetime'' burdens on the environment.)

A wet bulb temperature of 35 C is equivalent to a wet bulb temp of 95 C. That temperature is reached every summer here in the US in areas within 400 miles of the Gulf Coast, where the wet bulb temp is equivalent to the dry bulb temp due to high relative humidity. It is not uncommon in areas further north in the summer time. It is NOT equivalent to a heat index of 165. Get your facts straight.

At last, peace in the Middle East.

I have just done some research for the US prior to 1934,,,a record warm year. There were at least 24 places in 8 different states where the temperature exceeded 100°F., April through November. The average was 108°.

Add this science into the mix...http://www.smithsonianmag.com/...

https://m.youtube.com/watch?sn...

It's interesting because the denialists are mostlyuneducated and only listen to specific echo chambers in their tunnelvision,18th century view of the world that they refuse to change as legends in theirown mind.

I found it very enlightening and continuing to add to themonumental and overwhelming pile of evidence proving the man-helped climacticshift to extremes, that now in the Persian Gulf they are preparing for this global WARNING that is confronting them.

I didn’t see it in the news report, but this makes me wonderwhat’s gonna happen with the outliers, the countries around the Persian Gulf,who will have environmental pressures put upon them as well when the watersources in the Persian Gulf states evaporate and hundreds of millions of peopleneed to drink and have no public food markets for the daily vittles?

These are serious concerns for the plight of humanity andall who believe...

... that every life matters.

Reprinted with permission of MIT News