Global warming could push the sun-baked counties of the Persian Gulf to experience temperatures that are simply very hot for human habitability. Heat and humidity would be at the highest peak and even the healthiest people won't be able to bear it for more than a few hours outdoors.

The journal Nature Climate Change reported that booming counties, such as Abu Dhabi, Doha and Dubai, could cross the verge if temperatures continue to increase at current rates. After these booming counties comes the Saudi holy city of Mecca.

According to the report's authors, a pair of scientists from the Loyola Marymount University and Massachusetts Institute of Technology said that people of those counties on hottest days could seek an amalgamation of heat and humidity so high that the human body won't be able to shed the surplus heat through perspiration.

The authors wrote, "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 report scrutinizes different outlines over the coming decades, paying attention on a key heat measurement which is known as the 'wet-bulb temperature' that includes evaporation and humidity rates, averaged over many hours. The survivability limit for healthy people is considered to be 95 degrees.

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. 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.”

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.”

The report is the latest to highlight dangerous weather extremes that could be experienced in the relatively near future if atmospheric concentrations of heat-trapping greenhouse gases continue to rise at current rates.

Scientists said that if global warming continues, it could cross 95 degrees in certain parts of globe in future centuries. The researchers added that for counties in the Persian Gulf, the day would come a bit sooner, where temperatures will go beyond 110 degrees in the summer months.