Iran's decision to declare a two-day public holiday due to an extreme heatwave is a stark reminder of the growing public health risks caused by climate change. With temperatures forecasted to reach a scorching 50°C (122°F) in parts of the country, the government took the unprecedented step of shutting down offices, banks, and the stock exchange. This nationwide shutdown is likely the first of its kind in response to extreme heat, but it follows numerous localized restrictions imposed during the hottest months on record.
Heatwaves have increasingly disrupted daily life around the world. Schools in India, Mexico, and the Philippines have sent children home or adjusted teaching hours. Greece temporarily closed the Acropolis and imposed work restrictions to combat wildfires. Phoenix closed hiking trails as temperatures reached a record 110°F (43°C) for 31 consecutive days. As heatwaves become more intense each year, there may be more restrictions and measures implemented to protect vulnerable populations.
According to a recent report by Climate Central, over 6.5 billion people – 81% of the global population – were exposed to climate change-induced heat in July alone. The International Labour Organization estimates that, by the end of the decade, the accumulated financial loss due to heat stress worldwide will reach $2.4 trillion. The report also projects a yearly decrease of more than 2% in working hours. With the Earth already 1.2°C warmer than pre-industrial levels, climate models predict even more extreme temperatures in the future unless urgent action is taken to reduce greenhouse gas emissions and strengthen public health infrastructure.
Several factors have contributed to the intensity of this year's heatwaves. The position of the jet stream, strong bands of westerly winds, has trapped high-pressure systems over Western North America, the Mediterranean, and southern Asia. These weather patterns have concentrated intense heat for extended periods. Record-breaking ocean temperatures have also contributed to the bending of weather patterns, pumping humid air into land areas and exacerbating heatwaves.
Heat-related deaths are challenging to measure accurately as they can be attributed to underlying causes. However, they are known to cause significant harm. In the United States alone, the Bureau of Labor Statistics records more than 400 deaths from heat exposure since 2011, with thousands more hospitalized annually. A study found that Europe experienced over 60,000 excess deaths due to heat stress in the summer of 2022. In India, nearly 100 people died in June due to higher-than-usual temperatures, and Japan and South Korea recently faced sweltering heat that resulted in 15 fatalities. The World Health Organization emphasizes that even small deviations from average seasonal temperatures can lead to increased illnesses and deaths.
Extreme heat poses multiple health risks, including cramps, heat exhaustion, difficulty in breathing, heatstroke, hyperthermia, and increased likelihood of injuries. Humidity exacerbates these risks by reducing the body's ability to cool down through sweating. Heatwaves also put a strain on healthcare systems, especially in lower-income countries like Iran, which already experience high temperatures and have limited resources. Water shortages and poor air quality further compound the challenges faced by healthcare systems.
Moving forward, countries need to develop comprehensive contingency plans to effectively manage heatwaves. This should include implementing health warning systems, increasing hospital capacity, and establishing regulations to ensure workers are not exposed to excessive heat. As temperatures continue to rise around the world, heatwaves will become an increasingly relevant and pressing issue that requires proactive measures to safeguard public health and mitigate the socioeconomic impact.