The climate crisis has made heatwaves more likely and more intense around the world. Record-breaking high temperatures are being reported across the world. According to international data, the first week of July 2023 was the hottest week on record, putting millions of people in danger. All throughout this summer, recurring heatwaves have been affecting large portions of Asia, Europe, and the United States, priming the land for fires in places like Greece, Spain, and Canada, triggering unhealthy air warnings, evacuations, and heat-related deaths. The increasingly threatening effects of the climate crisis are also felt in cities worldwide, as extreme heat proves to be a rapidly growing health risk to millions of urban dwellers.
Cities are on the front lines of this public health emergency. People living in urban areas are among the hardest hit when heatwaves happen, partly because of urban heat islands. This is a phenomenon that occurs when cities replace the natural land cover with dense concentrations of surfaces that absorb and retain heat, like pavements and buildings. Heat risk levels also vary by neighborhood, with less affluent and historically marginalized sectors being the most affected due to the density of the population, limited access to cooling systems, and the limited availability of green urban spaces.