Extreme heatwaves are becoming more frequent, and the consequences on human health are alarming. With the world having recorded its two hottest days ever just last month, 2024 is on course to be the warmest year recorded.
The increase in high temperature events, along with humidity, pushes the limits of what our bodies can tolerate. For example, during the Hajj pilgrimage earlier this year, more than 1,300 lives were lost as temperatures soared to around 52C (126F), indicating the severity of these conditions.
Heat-related fatalities are not confined to the Middle East. Reports of such deaths have surfaced this year from several regions, including the U.S., Thailand, India, and Mexico.
Europe isn’t immune either; last summer, over 47,000 deaths were attributed to high temperatures, and experts continue to issue alerts as the summer progresses.
So, why is extreme heat so perilous? There are various factors at play, with dehydration being one of the most significant risks. It greatly increases the chances of heart attacks and strokes.
High temperatures can also exacerbate existing respiratory problems, particularly where air quality is poor. The constant exposure to heat stress diminishes people's ability to work and raises the chances of workplace injuries.
It's challenging to get accurate data on yearly heat-related deaths, as many cases go unreported. For example, cold statistics noted approximately 61,672 deaths linked to heat in Europe for 2022, but many experts believe the true number could be even higher.
Emerging economies often bear the brunt of these severe heat conditions due to limited access to cooling solutions. These are regions where most people work outdoors, and temperatures can be relentless.
Urban environments, with their concrete and asphalt, trap heat and intensify temperatures during nighttime, thereby aggravati ng heat stress. Studies show women and elderly individuals tend to be the hardest hit by extreme heat.
Using indicators like the humidex, heat index, or apparent temperature is becoming more commonplace for weather forecasters to assess health risks associated with heat. One such measurement, known as “wet-bulb” temperature, adjusts for humidity, which plays a significant role in how the human body tries to regulate itself.
For example, if temperatures reach 42C with 40% humidity, the wet-bulb temperature will be approximately 30C. Conversely, the same 38C at 80% humidity results in a wet-bulb temperature of around 35C, which can be deadly, even for those with optimal hydration and shade.
Over the years, methods for measuring wet-bulb temperatures have evolved. Initially, it involved wrapping wet cloth around thermometer bulbs, but now, technology allows for precise electronic measurements at weather stations.
Traditionally, wet-bulb temperatures were highest across South Asia and subtropical areas. Some parts of India have recorded wet-bulb temperatures exceeding 32C.
Studies predict India may be one of the first nations to surpass the critical wet-bulb temperature of 35C. With climate change impacts intensifying weather events globally, higher temperature records are anticipated across various equatorial regions.
Even locations long considered temperate are feeling the heat, with the UK, for example, recording its highest temperature at 40.3C just last summer. Meanwhile, areas like Barcelona have also been logging their hottest days to date.
What does this mean for the economy, though? Extreme temperatures complicate daily life and intensify existing inequalities - especially for city dwellers. Notably, even cooler locations see the economic effects, primarily through hikes in food and energy prices.
For example, coffee prices surged this year due to unfavorable weather conditions affecting supplies, especially from Vietnam, the world's leading producer of the commodity. Similarly, persistent drought conditions have prompted forecasts to drop for wheat production, alongside other crops sensitive to heat.
The phenomenon of El Niño has historically exacerbated the economic impact of extreme weather. For example, past events significantly affected both energy and commodity prices and are expected to do so again.
Rising temperatures have also contributed to higher electricity demands, which strains power grids and spikes consumer costs. Natural gas prices surged this summer as many consumers faced blackout risks, prompting Egypt, usually known as a fuel exporter, to start buying LNG to meet burgeoning demands.
Extreme heat not only disrupts day-to-day life but also threatens outdoor events, from concerts to sporting matches and religious gatherings. These disruptions accentuate the urgent need for adaptation and response strategies.
How does extreme heat connect to climate change? A new field of study, called extreme event attribution, rigorously links global warming to specific severe weather phenomena. The direct causation of heatwaves can often be traced back to increased greenhouse gas emissions from human activity.
Heatwaves, when combined with dryness and high winds, can endanger entire regions by intensifying wildfires, particularly evident across the western United States, Australia, and other ecosystems experiencing elongated fire seasons.
The rate at which tropical cyclones intensify is increasingly alarming as well. Scientists have observed climate change is amplifying these storms, with Hurricane Beryl's uncontrolled fury serving as a recent example.
Extreme heat and humidity serve as the frontline of climate change manifestations, pressing the need for immediate and effective action.
