In June 2023, the planet experienced its hottest month on record. In Iran, the heat index reached a staggering 66.7 degrees Celsius, pushing the boundaries of human endurance. This alarming trend is not an anomaly. It is a stark reminder that temperatures will continue to rise as climate change intensifies.
Scientists are linking the rise to human-induced climate change and the El Niño phenomenon. Additionally, the natural warming of Pacific Ocean waters is being further intensified by global warming.
That does not imply the highest temperature ever recorded since the Earth's formation around 4.5 billion years ago, but rather the highest within the last few millennia. Michael Mann, a climatologist at the University of Pennsylvania (USA), referring to a 2021 study, suggests, "It is certainly plausible that the recent days have been the hottest in the last 120,000 years or at least in the last 23,000."
Heatwaves are currently sweeping through multiple regions worldwide, including Europe, the United States, and Asia. In Brazil, scientists are particularly concerned about the increased risk of wildfires, especially in the Amazon region. In June, the Amazon rainforest and the Cerrado savanna experienced record-breaking wildfires, surpassing levels not seen since 2007.
How can we adapt cities to extreme heatwaves?
Crossroads
When the Dutch city of Arnhem devised a new plan to combat extreme heat, they considered reimagining their roads as part of the strategy. They recognized that the more paved areas in a neighborhood, the stronger the urban heat island effect, as these surfaces absorb heat during the day and release it at night. Arnhem is now evaluating which roads are underutilized, to reduce traffic lanes and replace some asphalt with greenery. Additionally, the city is planting trees along bike paths and sidewalks to provide extra shade, creating new shaded parks and ponds as cool spots for residents, and identifying areas that should remain open to help regulate temperatures.
Redesigning Public Spaces
In Abu Dhabi, where temperatures have recently reached 50 degrees Celsius, the city is testing various features to enhance outdoor comfort during extreme heat. These features comprise parks with blinds designed to open at night, releasing accumulated heat, strategically placed walls to direct cooling breezes, shaded seating areas, and misting devices that spray water to provide additional cooling.
Planting Trees
Low-income neighborhoods tend to have fewer trees, leading to a lack of shade that can make these areas at least 5 degrees hotter. To address this issue, some cities are using tools like the Tree Equity Score from American Forests to identify areas in need of more trees. Subsequently, they are implementing large-scale tree-planting projects to mitigate the heat disparity.
Cities like Dallas and Phoenix have focused on planting trees along the paths children take to reach elementary schools. Medellín, Colombia, has developed a network of 30 "green corridors" adorned with thousands of trees to enhance walking and biking experiences throughout the city. However, any such initiative requires meticulous planning to ensure tree survival. In Madrid, a forest encircling the city aimed at cooling was unfortunately dubbed a "tree cemetery" due to the high mortality rate caused by drought. Consequently, some cities are revising their approach to urban forestry, emphasizing diversity in tree species and selecting those resilient to climate change.
Revisiting Old Cooling Techniques
In Abu Dhabi, where temperatures often exceed comfort levels, certain buildings are incorporating modernized versions of ancient cooling methods. For instance, the Al Bahar Towers, a 25-story skyscraper, is adorned with shades inspired by traditional Islamic latticed screens. These shades, equipped with sensors that open in sunlight, significantly reduce the need for air conditioning. Meanwhile, in China, where temperatures are consistently breaking records, architects are drawing inspiration from ancient "skywells," which are shaded courtyards designed to naturally attract cooler air.
White Paint
Applying a white coating to rooftops can reflect up to 90% of sunlight, resulting in indoor spaces being around 30% cooler and reducing the reliance on air conditioning. New York City provides free coatings for selected buildings, including low-income housing, and assists other building owners in accessing discounted paint and free labor. Emerging technologies, like the whitest white paint developed by Purdue University researchers, offer additional cooling benefits. Furthermore, cities such as Los Angeles are also coating roads to help lower temperatures in neighborhoods.
Hiring Heat Specialists
A growing number of cities are introducing new roles for "heat chiefs," recognizing the escalating risk of extreme heat and the urgent need for resilience. Jane Gilbert became the first Chief Heat Officer (CHO) in Miami-Dade County in 2021. In this capacity, she oversees initiatives such as tree planting, installing cool roofs and pavements, and upgrading low-income housing to reduce energy consumption for cooling. The county has also proposed a new decree to safeguard outdoor workers, ensuring they receive regular breaks and access to water when the heat index reaches 40 degrees.
Via Tabulla.
