Are cities ready for extreme heat?

Moving people to cooling hubs – shopping malls, for example – is one of the emergency measures local authorities can take during singular heat waves. But as longer and longer bouts of high temperatures begin to turn into chronic high heat, city leaders must find ways to constantly try to counter the rise in temperature caused by global warming.

Shade and transpiration from trees can cool surface temperatures by up to 20 degrees Celsius (36 degrees Fahrenheit) compared to those exposed to the sun. In Miami-Dade County, Jane Gilbert and the Resilient305 Collaborative seek to increase the canopy of urban trees from a meager 20% to a more acceptable (but bare minimum) 30% through, among other things, gifts from trees. The plan is to prioritize areas that currently have the lowest forest cover.

Cities can also add artificial shade, such as bus stop canopies and covered playgrounds. These shade structures cannot cool surfaces as much as trees, but can still subtract 10 to 15 degrees Celsius (18 to 27 degrees Fahrenheit) compared to unshaded areas. As Gilbert says, “all shade is good”. Spread across hundreds of cities across the United States, these local adaptations will be crucial in saving thousands of lives.

Around the world, millions of people who would otherwise succumb to high heat could be saved if countries implement policies that reduce and stop the burning of fossil fuels. The United States alone could save 7.4 million souls across the planet if it meets President Biden’s goal of net zero emissions by 2050, according to a study by the Climate Impact Lab consortium. This does not even take into account other climatic hazards, just the heat. Acting today on the climate crisis at the local, national and international levels can protect millions of people from morbidity and death.

The heat is quiet. You don’t have to be.