To survive a heating planet, humans need shade—lots of it.
“Every year, heat takes more lives than floods, hurricanes, and tornadoes combined. The fatalities can sometimes go unnoticed, perhaps because the danger is invisible: There’s no twister that uproots a neighborhood and no flood that sucks it underwater, nor billions of dollars in property damage. Instead, heat’s imprint is seen in empty streets, work slowdowns, cognitive decline, and hospital bills. When autumn arrives and temperatures relent, heat leaves no discernable trace.
The Earth is getting hotter. In many places on the planet, summer is already two to three weeks longer than in the 1950s. By the end of the century, the warm season in the United States could last six months, and extreme temperatures could force us to spend much of it indoors. Supercharged heat waves will settle over cities for weeks at a time and cause many people to die. Others will suffer heart attacks, kidney disease, and brain damage. What we now call winter will be a brief, two-month interregnum that feels more like spring.
[..] even if every single power source becomes a renewable one and we stop emitting carbon, the planet’s surface won’t start cooling. The temperature will continue to rise for a few years before gradually leveling off. It will take “many, many centuries,” NASA estimates, to end the global-greenhouse effect. [..]
[Urban-planning and geography professor at UCLA V Kelly] Turner believes that shade could be America’s next long-term investment in public health. What safe drinking water and clean air were to the 20th century, shade could be to the climate-changed 21st. Scientific models bear her out. If we can get emissions under control and put the planet on a path to moderate warming, then by 2050, getting out of the sun could be the difference between unsafe heat and a livable environment. [..]
There is no technology that cools the outdoors as effectively as a tree. These communal parasols are also misting machines that dissipate heat. It’s hard to feel that effect under one or two of them, but get enough trees together and an urban summer can be as fresh as a rural spring, a feat with major implications for energy use and public health.
Where tree-planting isn’t viable, cities must invest in other types of public infrastructure that cast shade. [..] Ariane Middel, an Arizona State University urban-climate researcher who runs the school’s Sensable Heatscapes and Digital Environments (SHaDE) Lab, surveyed students and staff as they strolled through the shadows that solar panels cast on a Tempe campus thoroughfare. More than any change in ambient temperature, humidity, or wind, the mere presence of shade was the only significant predictor of outdoor comfort. [..]
As intense heat bears down, we have to see shade as a basic human right. We have forgotten that shade is a natural resource. We don’t grasp its importance, and we don’t appreciate its promise for a better future. Loggers and farmers cut down forests, forcing animals to flee and land to turn fallow. Engineers ignore time-honored methods of keeping out heat, locking us into mechanical cooling systems that fail during blackouts. And urban planners denude shady parks and pave neighborhoods with heat-sucking roads, only to drive us mad with the infernal conditions. But shade is a path to a better future—if we just learn to value it again, and design for it in the places we live.”
Full article, S Bloch, The Atlantic, 2025.7.22