Terrifying heat maps reveal the countries that will become too HOT to live in if global temperatures increase by just 1.5°C

What arrant nonsense! Amid the large daily temperature variations common in many parts of the world, an increase of 1.5 degrees would hardly be noticed.

I grew up in tropical Australia (FNQ) where a 38 degree Celsius (100F) daytime temperature was not uncommon. And it was usually humid too. We coped perfectly well. And we mostly had fair skin, blue eyes and spoke English. But we drank a lot of cold beer.

But I will concede that a degree of acclimatization may be needed to live comfortably in FNQ. Two generations of my family before me had CHOSEN to live in that area

The mistake made by the authors below may be thinking that residents of the Northern USA are typical of the human race

These frightening heat maps reveal the countries that could soon become too hot to live in if global temperatures increase by as little as 1.5°C (2.7°F).

Some 2.2 billion people in Pakistan and India's Indus River Valley, 1 billion in eastern China and 800 million in sub-Saharan Africa would be among those facing heat that is beyond human tolerance, researchers say.

That could extend to eastern and central parts of the US if temperatures on Earth were to rise by 3°C (5.4°F) above pre-industrial levels.

Residents in Florida, New York, Houston and Chicago would all have to endure dangerous and stifling levels of humidity, while extreme heat could wreak havoc among those living in parts of South America and Australia, according to the new study by Penn State University.

Humans can only endure so much heat before putting themselves at risk of a heart attack or heat stroke.

Record-breaking heatwaves across the US, Europe and China this summer once again threw the spotlight on just how much heat is too much for people.

Last year, researchers from Penn State revealed how the upper temperature limit for human safety was much lower than first thought.

Previously it had been thought that a wet-bulb temperature of 95°F (35°C) – equal to a temperature of 95°F at 100 per cent humidity, or 115°F at 50 per cent humidity – was the upper limit.

At this point the human body would no longer be able to cool itself by evaporating sweat from the surface of the body to ensure a stable body core temperature.

However, the latest research suggests the upper limit is actually 87°F (31°C) at 100 per cent humidity or 100°F (38°C) at 60 per cent humidity.

The key point to note is that it is not just about what the thermometer says. Instead, it is the combination of heat and humidity - known as the 'wet-bulb temperature'.

This is a direct indicator of how well sweating is cooling the body and is measured by attaching a wet cloth to the bulb of a thermometer.

In human history, temperatures and humidity that exceed human limits have been recorded only a handful of times — and only for a few hours.

In parts of India, Pakistan, eastern China and sub-Saharan Africa, residents would have to endure high-humidity heatwaves if global warming is not curbed.

These can be particularly dangerous because it means the air cannot absorb excess moisture, which in turn limits the amount of sweat that evaporates from the human body.

What is particularly worrying, the researchers said, is that many of the areas that would be worst affected are in lower-to-middle income nations who likely wouldn't have access to air conditioning.

In the worst-case scenario of global temperatures rising by 4°C (7.2°F), the port city of Al Hudaydah in Yemen – which is home to more than 700,000 people on the Red Sea – would be almost uninhabitable.

That is because residents would have to endure temperatures exceeding the limits of human tolerance on 300 days of the year.

'The worst heat stress will occur in regions that are not wealthy and that are expected to experience rapid population growth in the coming decades,' said co-author Matthew Huber, of Purdue University.

'But this research shows that humid heat is going to be a much bigger threat than dry heat.

The new study has been published in the journal Proceedings of the National Academy of Sciences.

https://www.dailymail.co.uk/sciencetech/article-12610895/Terrifying-heat-maps-reveal-countries-HOT-live-global-temperatures-increase-just-1-5-C.html

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