Non-survivable humid heatwaves for over 500 million people

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.

At the Business as Usual-scenario many billions of people would experience WBT higher than 32°C on a regular (e.g. yearly) basis, which is already deadly for the less fit and makes working outside impossible.

35 thoughts on “Non-survivable humid heatwaves for over 500 million people”

  1. Why is there no citation of the MIT research, even though it is the basis for all the claims in this article?

    1. Thank you for publishing this clear report. We need more reporting like it. I’ve worked on climate resiliency for many years. Governments have not treated it with the urgency it requires because in part due to ambiguous or overly optimistic scenarios.

  2. I’m genuinely crying right now. Tears are streaming down my face right now because this is showing that the poor souls who have the least ability to have a say in what goes on in the world around them are the same people who are going to be getting murdered by the conditions we’re directly responsible for… And we live in a world where “market” shares are more important and pressing than altering the course of the future before it’s too late. I’m going to stand up to this and one day soon my voice will be heard. And I’ll ensure that the people’s voices who are drowned out the most are heard. I can’t save the world by myself though. We need a movement that hits people in waves, stops them in their tracks of their mediocre life and makes them think “there’s a bigger picture to all of this, there’s a greater cause, and my individuality can make a positive difference”.

    My name is Ivan Volkov and I’m 19 years of age. I was born in Ukraine and I now live in the UK. I’ve seen the extreme ends of the spectrum in terms of wealth and poverty, and I am joining the movement to save the planet. It has no name other than the movement because it resembles the people’s voices that go unheard on a daily basis because of the circumstances they were born into. I’m not only doing this for the timeline that I’m currently living in, but also the timeline that is to be ahead of my death. This is one which many people can’t grasp the concept of, life will continue after their death, so ensure that life has the best opportunities possible in terms of the environment around them. Sustainability is key. Please help me because I can’t do this on my own. I’m begging someone see’s this. I can’t see news stories like this any longer.

    1. Dear Ivan. Your comment moves me. The reason we wrote this article is because we hope that everybody gets the full picture of what climate change may become if we do not do anything. Let us all join the same movement to save the world. Today there a climate march in The Netherlands where 40,000 people marched in the pouring rain with strong wind in 5 degrees Celsius for hours. A lot of normal families too. We have a long road to go, but people slowly seem to be waking up.

    2. We are in this together and together is the only way to find a way out. My fear is that this is just our future reality until real action happens and more than the troubled few are alarmed enough to try to act. I have shd my tears many times over what is happening and my heart is more often heavy that light. I’m trying to help show a path.

    3. You aren’t alone. join extinction rebellion we are global and getting bigger. Good luck

    4. Dear Ivan, you are not alone. We are with millions, we need to rise up and will rise up. It is already happening. Talk to people near you, join groups like Extinction Rebellion, or join facebook groups like Global Warming Fact of the Day, connect and fight, we all have to. You can mail me if you like, take care, Rob

    5. Ivan, I am 73 and will be long gone before 2070. But, my heart and mind are sick with grief knowing what lies ahead for my grandson, granddaughter, and the millions of “voiceless” people. I will be marching with young students on 3/15 and I join hands with you and everyone else that understands the crime against humanity and all creatures of this Earth committed by the extraction industries. You are not alone Ivan. There are millions of us. And we meed to act together…

    6. Dear Ivan , you are not alone in this.We must try and create awareness and living with consideration for the planet.There is many people of your generation that will be able to work together to effect change.There is many projects like Ocean Clean up and stuff happening and you all give me hope.I am 70 years old and getting ready for the next round but know that there is continuity and hope to help now and always

  3. What MIT research is this referring to?
    As the basis for everything in this article, this research should be cited.

      1. Hi Admin,
        could you please correct a typo that the opposition will seize on to pooh pooh the whole thing: “Many” billions – There’s only 7 billion of us on Earth, so some subset can’t be “many”

        1. Thank you for your comment. By 2050 we will already be over 9 billion. RCP 8.5, which this article refers to, assumes 12 billion by 2100. I do not know what qualifies as a subset of what number to be able to use the word ‘many’, but did try to emphasize in the article that we are probably not talking about 1 or 2 billion people, but maybe quite a few billion more.

  4. I suspect once Arctic ice free sometime in the 2020s we will see an abrupt jump in global temps. We know for a fact that Climate Scientists have been far too conservative with their predictions, For example just ten years ago they predicted Arctic ice free sometime after 2100. We have already locked in 4 to 6 C global temp increase(self extinction due to Canfield oceans with its H2S). Loss albedo as we transition away from burning stuff implies something around a 2 C global temp increase all by itself. Live each day fully I suggest,

    1. Aside from more sunlight being absorbed by water than by ice… As long as there’s a significant amount of ice in a body of water, it can take in a lot of heat without the temperature increasing. Once that body has gained enough heat to melt the ice, any further heat input goes directly to raising water temperature.

  5. Horrible, horrible news. Everyone of us has to step up and do the most that we can. To give people ideas, I and now five volunteers have been building a website for two years that lists personal, social/collective, and political steps people can take, of all kinds. we also have a great Facebook discussion group where we share ideas and support one another. And we just got started on Twitter and Instagram. So if you want to fight, check us out. Also partnering with Earth to build an app.

    Please step up. Thank you.

  6. I’ve travelled all over the world. I’ve seen the effects of climate change. From glacial melting, bushfires and droughts and extreme storms. It rages me that the leadership of the world does nothing or says the market will sort it out. It won’t. It has to be lead by government. Every time I see the weekly co2 concentrations rising i feel nauseous. My son is 2 years old I am 40. In my lifetime a human catastrophe will happen that makes the drought in pre war Syria look like childsplay. I am a second year climate change student. In hindsight it could have all been avoided or highly mitigated. When will the world wake up.

  7. You can also take a look to this other article, published in Nature Climate Change in June 2017.
    Although the simulations are different, the results are quite similar. But there, *all* the lands between the tropics seem to be particularly affected (including African and Oceania) : see fig.3

    ‘Half a billion of people at risk’ might actually be a lower expectation.

  8. Our Climate is changing day by day. We, the Bangladeshi people are the worst victim of Climate change. Saline water is coming up from the Bay of Bengal and we losing sweet water. Our land is losing fertility for salinity. We are so many people (more than 160 million) within this small country (147,570 km²). Heat is also increasing. We are the climate victim but our contribution to climate change is less than 0.1% because still it is an agrarian country, no heavy industry. Most of the world leaders admit that climate is being change but Mr Donald Trump. We would like to convene him to visit Bangladesh to see what is going on our coastal area.

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