Rising temperatures will threaten the survival of 2 billion people

Perhaps we are not aware enough of it, but we live in certain places not by chance. Or rather: the distribution of the population worldwide is concentrated in more favorable areas from a climatic point of view, to the point that it is possible to identify a sort of “human climate niche”, as the researchers call it. We cannot, in other words, live anywhere. And if temperatures continue to rise, more and more people will find each other away from home, out of our climatic niche, with the risk of not being able to work, move and live due to the excessive increase in temperatures. How many people are we talking about? Two billion in the event that temperatures at the end of the century will have reached 2.7°C compared to pre-industrial levels.

To come to terms with the costs of climate change on health is a study just published on Nature Sustainability, in what sounds like yet another appeal in the fight against climate change. In an attempt that, estimates other than economic and environmental costs, can serve to awaken policies and consciences, the authors suggest. In fact, the stated intention is to deal in terms of ecological risk for the human species, rather than in terms of the economic costs of the environmental crisis.

The starting point was the analysis of the population distribution as a function of temperature and historically, the authors write, we tend to live around two average annual temperature peaks: one around 13°C, the other around 27°C. With the increase in temperatures, however, something is bound to change: more and more people will find themselves living out of nicheand in areas with higher temperatures, with all the associated dangers.

In fact, the increase in temperatures – starting from 28°C – not only means leaving one’s comfort zone, but is associated with reduced productivity at work, cognitive and learning difficulties, premature births and low birth weight and mortality , recall the authors, led by a team of Global Systems Institute of the University of Exeter. To all this – they continue – must be added the risks of conflicts and migrations, also linked to the increased risk of transmission of certain diseases and the difficulties that the increase in temperatures produce on agriculture and livestock, without considering other effects of the changes climatic, such assea ​​level rise.

How many people at risk are we talking about? It depends on how much temperatures will rise by the end of the century and on the trend of the population itself. In worst-case scenarios, where temperatures even reach and exceed 4°C – with a return to fossil fuels – about half of the population would be outside their niche.. Assuming instead that things proceed as they do today, the increase in temperatures should stabilize at around 2.7°C by the end of the century, leading away from home – that is, outside the human climatic niche – about 29% of the population, just under three billion people out of an estimate of 9.5 billion. Approximately 22% of the population would instead be exposed to high temperatures: it would be much less, 5%, if the target for the increase in temperatures reached that 1.5°C of the Paris agreements, thus going from 2 billion to 400 million people exposed (today there are about 60 million, due to increases of not even one degree that have already occurred).

The report

Record heat also in the next 5 years: the estimates of the World Meteorological Organization

edited by the Green&Blue editorial team

May 17, 2023

If the population were to grow even more, the more people will be at risk, because while it is true that population densities can change, population growth tends to be concentrated in the hottest places, according to the paper. With this in mind, the areas most at risk with increases of 2.7°C would be India, Nigeria, Indonesiathe PhilippinesThe PakistanThe SudanThe Nigerthe ThailandL’Saudi Arabia and the Burkina Faso.