Extreme heat harms health — what is the human body’s limit?

This summer's extreme heatwaves in the Northern Hemisphere have made it difficult for people to stay cool. Credit: Getty via Patrick T. Fallon/AFP

The summertime in the Northern Hemisphere this year has been exceptional. Mexicali, in northern Mexico, saw scorching temperatures in July of 47 °C, which made residents stay indoors to prevent fainting and dizziness. A heatwave in June and July claimed at least 167 lives throughout Mexico. A weather station in the Xinjiang area of northwest China recorded 52.2 °C in July, while Death Valley in California recorded a scorching 53.3 °C. Furthermore, in August, extreme humidity and temperatures at Iran's Qeshm Dayrestan airport created an environment that would quickly kill healthy individuals.

Cities need to shield residents from intense heat.
The current heatwave in North America emphasizes how important it is for urban planners to consider excessive heat when creating measures for climate adaptation.

The heat wave that hit the western United States and Canada last month broke all previous records for temperature. The Canadian town of Lytton recorded a temperature of approximately 50°C on June 29, which was an incredible rise of nearly 5°C over the previous national record.  During the same three-day heatwave, hundreds of people died in the cities of Vancouver, Portland, and Seattle.

cool hallways
Paris is leading the way in this idea of "heat equity," as city officials are creating a network of "cooling islands" connected by cool walkways that span the entire city and include areas like parks and swimming pools. Concurrently, Medellín, Colombia, has focused on planting trees in low-income sections of the city; over 10,000 trees have been planted along 36 "green corridors," which have reduced surface temperatures by 2°C. To green their cities, government authorities need to keep an eye on the outcomes of these projects and apply the best available data.