The Chilling Reality of Global Warming Around the World

Strange weather phenomena have led many people to doubt that the earth is warming up. New York receiving snow during the second weekend of May, for example, has left many of us climate change believers scratching our heads: if global warming is real, then why is there snow in May? In reality, climate change has everything to do with these recent weather patterns, and here’s why.

The earth’s stratosphere is divided into several regions known as wind cells, or zones of warm wind that rise up in the stratosphere, cool, and fall down as cold wind. These wind cells get progressively colder in higher latitudes because of the cold air coming from the poles. These temperature differences are usually the smallest during the summer because that is when the North Pole receives constant sunlight, heating the wind and counteracting the natural cold of the poles. Because the poles get less sunlight during the winter, temperature differences become more extreme over these months. Bouts of cold weather in hotter months like May occur because of disturbances to the polar vortex, wind cells in the earth’s polar regions. These extreme temperature differences create the polar cell, a low-pressure zone that rotates like a cyclone, hence the name “polar vortex.” The polar vortex is stable because the differences in temperature and pressure around it balance it enough to keep it in place year-round.

However, the vortex separates into multiple fragments if it destabilizes. This separation occurs because the temperatures in the northern regions increase due to global warming. When the Arctic polar vortex weakens and fragments, the cold air in that region is set loose, allowing it to move to other areas, like the Northeastern coast of the U.S. This shift also allows the hot air around a weakened polar vortex to push inward, displacing the once cohesive region of cold air and causing it to move south. In addition, this process moves the polar jet stream, the region between two wind cells, further south. Because warm and cold air meet at jet streams, it creates a “stream” of fast winds blowing from west to east. This is responsible for predictable weather patterns around the world. Without it, some regions would never see the sun while others may never receive rain. As the jet stream moves, it brings cold air to new regions. When the cold and warm air mix, we get more erratic weather patterns, such as snow in May.

While the Western Hemisphere experiences these strange weather phenomena, global warming is also threatening the lives of many in other regions around the world. As cold weather creeps down from the north, increasing temperatures promote hot and humid conditions in subtropical regions of the world, such as the Persian Gulf and South Asia.

Niche global climate trends have revealed an increase in moist-heat events—instances of heat stress in tandem with high air moisture—popping up throughout the globe. Climate scientists studying weather data from several thousand global weather stations have noticed this unnerving trend arising in the aforementioned subtropical coastal regions. A study done by NASA scientist Colin Raymond and his colleagues, who scoured decades of weather station data from 1979 to 2017 for cases of extreme moist-heat conditions throughout the world, shows this as well. These instances of extreme temperatures had frequently been overlooked in statistical simulations due to a lack of previous consideration for the dangers of humidity in the context of meteorology and climatology. These simulations are intended to estimate when regional climates will surpass the extreme moist-heat threshold that humans cannot survive. While the first occurrences of deadly temperatures have been predicted to hit by the middle of the century, Raymond’s findings show that they have already been observed.

“Wet-bulb” temperature simultaneously serves as a measure of humidity and temperature. Wet-bulb temperature is conventionally measured using a thermometer wrapped in a wet cloth and operates on the principle that higher air humidity reduces the rate of water evaporation occurring on the cloth. This measure serves as a standalone way of indicating the temperature we feel based on real temperature and air humidity. The physiological capacity in terms of wet-bulb temperatures is approximately 95℉ (35℃), in which the human mechanism of sweating to cool off the body is rendered ineffective. In high moist-heat conditions such as this, even someone with unlimited access to water would likely die in less than a day. Even wet-bulb temperatures between 88 and 91℉ (31 to 33℃) correlate to increased mortality rates during heat waves.

Raymond and his colleagues observed increasing wet-bulb temperatures originating in subtropical coastal regions, where the combination of seawater evaporation and hot air creates extreme moist-heat conditions. As global temperatures rise, evaporating seawater increases air humidity, creating said conditions. In South Asia, monsoon winds also contribute to the flow of humid air, which causes additional moist-heat events inland.

When compared to previous estimates regarding the onset of critical weather conditions, Raymond’s study warns that some regions of the world will be rendered uninhabitable much sooner than previously thought. Despite notions that 95℉ wet-bulb temperatures would not be observed until the middle of the century, some brief occurrences have already been documented, and Raymond predicts that parts of South Asia and the Middle East will be rendered uninhabitable by the third quarter of the 21st century. Based on the U.S. National Oceanic and Atmospheric Administration heat index, 95℉ wet-bulb temperatures at high humidity can reach more than 130℉ in perceived heat. In the last four decades, cases of extreme humid heat have also doubled in frequency across the globe.

Rising global temperatures are a primary focus of most environmentalists, while the additional conditions created by increasing moisture have often been overlooked. The trend has raised questions regarding future plans for cooling solutions in rapidly warming regions. Some wealthier countries in the Middle East, where off-the-charts moist-heat conditions have been observed, have begun moving their economies indoors and finding means of cooling outdoor regions. Other less fortunate nations with agricultural economies are more vulnerable to extreme heat conditions. Based on upward global warming trends, climate scientist Jonathan Buzan estimates that unsurvivable heat conditions may last several days per year in the coming years. As global warming continues, we may need to grow increasingly aware of the additional niche climate conditions that it brings.