There has been a lot of talk about climate change for years, but for most people it remains an abstract concept. This is because most of us have been spared its most devastating consequences.
In a manifestation of a warming planet, billions of people could soon be exposed to such high levels of heat that spending longer periods outdoors during the sweltering summer months could prove fatal.
Parts of the planet, like the Sahara desert, are no longer suitable for people other than the harshest of souls. However, other regions with currently temperate climates could also get too hot for much of the year. Once heat stress levels rise to a certain threshold in these areas, millions of people could suffer serious health effects, experts warn.
Elsewhere on the planet, in other words, a warmer climate "will pose a greater risk to human health," says Tom Matthews, a climate scientist at Loughborough University in the UK. "[We can] say that we are universally creeping close to this magical threshold of 35 ° C," he clarifies. "It appears that, in some cases for a short period of the day, we have exceeded this value."
Matthews has come to this conclusion after analyzing data from weather stations around the world with his colleagues. What they found is a marked increase in the recurrence of so-called wet bulb (WB) temperatures (which is a measure of heat and humidity together) that exceed limits that we can still safely manage.
Beyond a WB threshold of 35 ° C, our bodies can no longer cool off by sweating in humid climates. Just think about staying in a sauna for a long time. As a result, we are likely to experience heatstroke and organ failure because the core temperature of our bodies is still too high. However, since 1979, the frequency of dangerous heat waves has doubled in countries such as India, Pakistan, parts of the United States, and Mexico.
Even across much of Europe last summer, thousands of people succumbed to extreme heat during long periods of unusual heat. Scientists say that not only will such deadly heat waves become more common, but they will continue to impact more and more people in an ever-larger area.
According to a new study, in just a couple of generations (in half a century) up to 3.5 billion people could find themselves living in areas that are too hot for humans for much of the year.
Today, the planet appears to be on track to warming 3 ° C on average by the end of the century, making much of the planet uninhabitable for humans. Because land areas are warming faster than oceans, temperatures in certain parts of the world could rise up to 7.5 ° C by 2070. The worst affected regions will include Sub-Saharan Africa, South America, Southeast Asia, the Arabian Peninsula, The Indian subcontinent and Australia.
Prolonged droughts and other extreme weather events could make things worse for the people who live in these areas. "In the absence of climate mitigation or migration, a substantial part of humanity will be exposed to warmer average annual temperatures than almost anywhere today," warn the scientists behind the study.