In July, the world experienced the two hottest days on record, and 2024 is on pace to become the warmest year ever recorded. Heat waves are becoming more common, more severe, and arriving earlier than expected. When combined with humidity, extreme weather conditions are already pushing the limits of human endurance. For instance, more than 1,300 people lost their lives during the Hajj pilgrimage in Saudi Arabia in June as temperatures soared to around 52C (126F). Tragically, heat-related fatalities have also been reported in various locations this year, including the US, Thailand, India, and Mexico. Parts of Europe, where high temperatures led to over 47,000 deaths in 2023, are bracing for more extreme conditions this summer.
Causes of Danger in Extreme Heat:
There are numerous reasons why extreme heat poses a significant risk to health. High temperatures increase the likelihood of dehydration, which in turn raises the risk of heart attacks and strokes. Heat exacerbates breathing problems, especially in areas with high levels of pollution. Heat stress can impair work performance and increase the chances of accidents. The exact number of heat-related deaths is often underestimated and goes undocumented. Studies show that in 2022, Europe likely saw around 61,672 deaths due to heat-related causes, with emerging economies bearing the brunt due to limited access to shade, water, and cooling systems. Urban areas with extensive concrete and asphalt experience even higher temperatures at night, contributing to heat stress. Women and seniors have been identified as the most vulnerable populations during extreme heat events.
Methods of Measuring Extreme Heat:
Forecasters now use various metrics to assess heat stress and discomfort, such as humidex, heat index, or apparent temperature. The “wet-bulb” temperature is a critical measure that factors in humidity levels, making it harder for the body to cool itself through sweating. The combination of high temperatures and humidity can lead to heatstroke, even for healthy individuals with access to shade and water. Studies have shown that regions affected by deadly heatwaves in the past experienced wet-bulb temperatures as low as 28C. Technological advancements have made it easier to measure wet-bulb temperatures using electronic instruments at weather stations, aided by satellite data to identify hotspots.
Global Impact of Extreme Heat:
The effects of extreme heat are felt worldwide, with both traditionally hot and temperate regions experiencing record-breaking temperatures. Rising heat levels are impacting every aspect of life, creating challenges and exacerbating inequalities, particularly in urban areas. Supply chains for commodities like coffee and wheat are being disrupted, leading to price surges in global markets. Higher temperatures also lead to increased power consumption, straining energy grids and increasing costs for consumers. Droughts caused by extreme heat further affect agricultural production and energy generation. Outdoor activities are increasingly disrupted due to extreme temperatures.
Relationship Between Extreme Heat and Climate Change:
Extreme event attribution connects the rise in global temperatures to severe weather events, such as heatwaves, with specificity. Greenhouse gas emissions from human activities are directly linked to the occurrence of heatwaves. Climate change intensifies wildfires due to increased heat and dryness, while also making tropical cyclones more intense. Rising global temperatures have made extreme heat 30 times more likely in regions like India and Pakistan. Overall, climate change is exacerbating extreme weather events worldwide.