Sand During Drought

A World on Fire: Rising Heat Wave Temperatures Become the New Normal

Jane Marsh - March 11, 2024

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If the days feel hotter than usual, you’re not imagining things. Global warming is on the rise and with it, so are heat wave temperatures. While sunbathing on a hot summer day is undoubtedly relaxing, excessive heat is detrimental to public health, the environment, and the economy. 

The effects of heat waves are becoming all too apparent, especially as climate change has worsened in recent decades. But why are high temperatures more prolonged than ever and what are the global consequences of these events? 

Why Are Heat Wave Temperatures Worsening?

Last year, the Earth experienced the hottest four days on record worldwide from July 3 to July 6 — the culprit: Human-induced greenhouse gas emissions and an El Nino occurrence in the tropical Pacific Ocean.

Experts predict the warmest temperatures will rise 5 degrees Fahrenheit annually by mid-century and 10 F by late-century. Additionally, hotter temperatures combined with high humidity will create dangerous situations for every living thing. During the same timeframes, the number of days with heat indexes above 100 F will double in the United States, tripling with temperatures above 105 F by 2100.

What scientists consider the threshold for heat waves is relative to a particular area — heat wave temperatures will differ between Phoenix and Seattle. Regardless, the impacts will prove significant to each location. 

Consequences of Rising Temperatures

The U.S. Environmental Protection Agency explains how heat waves affect the human body. For instance, people must cool off at night after a scorching day. The heart has to work harder, while the body endures extra strain if nights remain too warm. 

Heat wave temperatures also cause droughts and wildfires, and can negatively impact various economic sectors, including tourism, infrastructure, and agriculture. In fact, crops exposed to three days of extreme heat during their 30-day reproductive cycle often produce 10% less yields. 

Maize, in particular — one of the world’s three primary crops — will undergo a 24% decline by 2030 due to hotter temperatures, posing a risk to global food security. Likewise, heat waves and droughts exacerbate the water crisis and accessibility to clean drinking sources in places like Africa and the Middle East. 

Across the globe, Canada is one of the most heat-impacted nations. For instance, experts blame the 2021 heat wave on Canada’s Pacific coast for the nearly 1 billion marine wildlife deaths that occurred, demonstrating ecosystem vulnerabilities to climate change. Temperatures in this area reached a scorching 104 F for five days straight. Hot, dry conditions also induced widespread wildfires in 2023 that sent choking smoke across the U.S. and caused thousands to flee their homes.

Global Impacts of Heat Waves

Every continent has felt the effects of rising heat wave temperatures in recent years. Europe is especially marred by its deadly 2019 heat wave, killing 2,500 people in France, Belgium, and the Netherlands. However, 2023’s global heat wave events were just as dire. Here’s what happened around the world last year.


Heat wave temperatures across the Mediterranean Sea reached a record high of 28.71 degrees Celsius, surpassing 2003’s record of 28.25 C — about 84 F and 83 F, respectively. 

While the 80s might feel comfortable to someone from the world’s hottest regions, these temperatures significantly damaged marine life in the Mediterranean, such as corals and mollusks. Warmer ocean temperatures could also drive heavy precipitation across Europe, risking flooding and other environmental and human impacts.


China is notoriously the largest emitter of greenhouse gases worldwide. As such, it should come as little surprise it also endures some of the worst heat waves. In June 2023, Southern China recorded temperatures of 95 F to 104 F for days with humidity.

As temperatures rose, electricity demand did, too. Unfortunately, 2,000 households in Shenzhen suffered power outages while running their air conditioners. In Guangdong, the city power grids exceeded the maximum power capacity of 200 million kilowatts — a historical record. Hainan, Guangxi, Yunnan, and Guizhou were also affected.

The heat wave sent several people to the emergency room while employees mandated workers return to work from an early lunch to stay out of the heat.


Unfortunately, Europe’s 2019 heat wave didn’t end that summer — 2023 broke new records across Germany and Italy. Italy suffered the most, with 127,000 people exposed to 104 F, compared to 4,000 people enduring high temperatures between 1980 and 1999. 

France also set new late-summer records for excessive heat in August — the hottest weather recorded since 1947. Weather experts predicted maximum temperatures of 107 F in the Aquitaine and Occitanie regions near Spain, and the Rhone Valley.

South America

Scientists blame climate change for the heat wave across South America from July to September 2023. Temperatures rose 4.5 degrees above normal, reaching 104 F in Argentina, Brazil, Uruguay, and Bolivia. 

Four people died from heat-related illnesses in Sao Paulo, Brazil. However, the actual death toll could take some time to determine accurately. 

Mitigation and Adaptation to Heat Waves

Globally, more countries will have to learn how to adapt to rising temperatures. To improve resilience to heat waves, cities should implement the following mitigation measures:

  • Develop Heat Emergency Response Plans, including forecasting, monitoring, and education strategies
  • Communicate heat warnings and educational information to the public when heat waves approach, such as news outlets
  • Raise public awareness to protect the most vulnerable populations like children and older adults
  • Build community cooling centers in underserved communities
  • Maintain public works systems and energy equipment
  • Create hotlines for public health officials, citizens, and high-risk people
  • Provide energy efficiency recommendations to decrease electricity demand and peak loads

Likewise, infrastructure improvements in urban areas will be crucial to offset the urban heat island effects. These updates include maintaining roadways, reducing transportation congestion, implementing green roofs on commercial buildings, laying cool pavements, and planting more vegetation. 

Today’s Heat Waves a Scorching Reality

Heat wave temperatures remain a top concern for health officials as they develop resiliency plans to combat climate change. Today’s excessive, dry heat is nothing to take lightly. Mitigation strategies must comprise public awareness and essential upgrades to prevent adverse effects, while everyone must do their part to protect themselves, their neighbors, and the planet.

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About the author

Jane Marsh

Starting from an early age, Jane Marsh loved all animals and became a budding environmentalist. Now, Jane works as the Editor-in-Chief of where she covers topics related to climate policy, renewable energy, the food industry, and more.