Researchers at MIT warn that if climate change remains unchecked (Business As Usual-scenario = RCP 8.5) over half a billion people will, from 2070 onwards, experience humid heat waves that will kill even healthy people in the shade within 6 hours. The Wet Bulb Temperature (WBT) would exceed 35°C (95°F), at which the body – of any mammal – cannot cool itself, overheats and shuts down.
Three regions were studied: China (2018), South Asia (2017) and the Persian Gulf (2015). The researchers predict (at RCP 8.5) WBT exceeding 35°C about once every decade for the Northern Plains in China (400+ million people), at locations in the Chota Nagpur plateau, northeastern India, and Bangladesh in South Asia (70+ million people). Persian Gulf regions that would be affected include cities such as Doha, Qatar, Abu Dhabi, Dubai (UAE) and Bandar Abbas (Iran).
Figure. 3 regions studied, worst areas in dark red.
The total number of people affected will be higher than 0.5 billion. A study in Nature (2017) identifies regions worldwide that are likely to exceed the survivability threshold from 2070 onwards (see Fig. 2). These also include the Eastern United States, Northern Latin America and Northern Australia.
Figure 2.Annual probability of occurrence of extreme humid heat waves at 4°C warming relative to 1861–1880 (which is likely by 2070 under RCP 8.5 scenario) of the level AT55°C (Apparent Temperature), which roughly corresponds to a Wet Bulb Temperature of 33°C, with peaks exceeding WBT of 35°C. Orange means that such temperatures will be reached every other year on average. Source.
Wet bulb temperatures higher than 33.5°C for more than a few hours have not been measured in human history (yet). In 2015 there was a severe episode in South Asia with 30°C WBT. This led to 3,500 deaths. According to this article the largest hospital in Karachi was receiving 1 patient per minute and the morgue was overflowing.
Would airconditioning be to avail? Podcast Ashesashes describes that a ‘perfect storm’ will hit power supply at extreme temperatures. Airconditioning at high temperatures leads to more than 20% extra power demand, while at the same the power grid becomes less effective, nuclear and gas fuel plants provide less power because of warmer cooling water and transformers are more likely to overheat leading to power outages. Also, it is hard to see how renewable energy could meet the peak demand. Without solutions, the areas mentioned would effectively become uninhabitable.
Cuckolded_snowflake on March 10th, 2019 at 03:47 UTC »
I live in South Australia. The fear of our future summers and what could happen is very real. 46°C (114°F) days are not for everyone.
niktereuto on March 10th, 2019 at 02:59 UTC »
Things like this don't just happen suddenly.
While the paper here says "from 2070 onwards", the first cases of this occurring will happen well before then.
At first, it'll just be something small. Maybe Dubai will hit 130 degrees with 80% humidity for a day or two one summer in 2030. A few people will die, but most people will be okay, thanks to air conditioning.
Then a few years after that, it will begin to spread and become more common. First Dubai, then Basrah and Bahrain.
It'll start off as a day or two of not being able to go outside due to extreme heat and humidity. A "warning", like a "clear the air" day or something. Not a big deal.
A few years later it'll be a few days.
A few years after that, a week.
Then it'll spread to other coastal cities that are near the tropic of cancer and tropic of capricorn. Mumbai. Colombo. Ho Chi Minh City.
That's when thousands of people will begin dying, every year, due to severe heat and humidity.
But we aren't done yet, because after that, it'll begin spreading to first world countries. Cities such as Darwin (Australia), Fukuoka and Osaka (Japan), Shanghai, Shenzen, Macau (China), Taipei (Taiwan), Pensacola, Tallahassee, Tampa, Baton Rogue, New Orleans, Houston, Mobile, Phoenix, and San Diego (United States).
At this point, the heat and humidity problems will have spread to the point where basically anywhere a hurricane can potentially form (plus a few other areas) has the potential to have severe, uninhabitable humidity at least part of the year.
Cities further away from the tropic of Cancer/Capricorn will maybe have one or two days of un-inhabitability- at least, for a while anyway. At this point, however, much of the middle-east is uninhabitable for 2 or 3 months of the year, causing severe political instability, wars, famine, etc.
Then we will hit the year 2070, and it will only get worse from there.
depreseedinparis on March 10th, 2019 at 01:32 UTC »
When i was a student in Iran, in the 70s, my teacher used to talk about this and was saying the only way to prevent this or lowering it's impact was to create a massive green belt from the Gulf of Oman to Hamun lake via the Luut desert and all the way up to the border with former soviet union north oh Mashad.
The muliti billion dollar project could create a 100m wide canal connecting the Hamun dying lake to the free salt water from Oman sea will have an enormous impact on the temperature and humidity of the whole region, both on the north and south sides of the Persian Gulf.
He actually met the agriculture minister and his idea was presented to Shah of Iran who was interested but the revolution of 79 put an end to that dream.
My teacher lost his job during the cultural revolution and was forced to make a living selling 2nd hand books until he died in 89.