Why We Need Shade in a Warming World

In Los Angeles County—famous for its sunshine—just 20% of urbanized areas are shaded at noon. That’s creating a serious health hazard for people who work outdoors, wait at bus stops or play outside. Environmental journalist Sam Bloch argues that shade should be considered a basic human right, akin to access to clean air and safe drinking water. We speak with Bloch about why modern cities have so little shade and how we can reintroduce it as a fundamental element of urban design. Bloch’s new book is “Shade: The Promise of a Forgotten Natural Resource.” Do you struggle to find shade in your community?

This partial transcript was computer-generated. While our team has reviewed it, there may be errors.

Mina Kim: Welcome to Forum. I’m Mina Kim.

We’re all familiar with the experience of desperately seeking shade to escape the glare of the sun — deliberately crossing the street to walk on the shaded side, or finding the shade of a lone tree at the edge of a sun-bathed lawn. Shade can make it feel cooler by some twenty degrees and cool surfaces by more than double that. And with an increasingly warming planet, it can save lives.

But we haven’t valued it enough — in fact, we even have a bias against it, says Sam Bloch, who has looked at what it will take to provide more shaded areas and why it’s more complicated than it sounds.

Bloch’s an environmental journalist, and his new book is called Shade: The Promise of a Forgotten Natural Resource. Welcome to Forum, Sam.

Sam Bloch: Mina, thanks for having me. It’s great to be here.

Mina Kim: Glad to have you. So — we haven’t always devalued shade, right? You discovered in your reporting that ancient cities likely organized themselves around it?

Sam Bloch: Yeah, that’s right. I think when most of us think of shade, our first thought is probably trees — for good reason. But long before anyone had the idea of planting a tree on the street, or what we’d call a backyard or front yard, or creating a leafy park, urban people in really hot environments were making shade from the city itself — the buildings and the walls around them.

In my book, I write about the Mesopotamian city of Ur, in the Fertile Crescent — modern-day Iraq — one of the cradles of human civilization. Thousands of years ago, Ur and likely many other cities were probably designed specifically to create shade and protect from the sun.

The houses back then were about ten feet tall, packed so close together that they left only narrow, five-foot-wide alleys — like canyons — for people to walk through, which meant hardly any direct sun exposure.

Something else in Ur and other ancient cities: most American cities today are oriented on ninety-degree grids laid out in the 18th and 19th centuries. But back then, cities were oriented diagonally at forty-five degrees. That diagonal grid caught prevailing winds and meant the city cast equal amounts of sun and shade on streets and buildings throughout the day.

Between the narrow “urban canyon” layout and the diagonal orientation, pedestrians could move through a continuous shadow network, traversing the city out of the sun’s glare.

An archaeologist I spoke with told me she believes one reason cities took off in this part of the world — why people left scattered villages for urban centers — was for the shade they created. Life on the plain was probably incredibly hot, under a fiercely destructive sun. Shade was a draw.

It’s a fascinating way to think about the purpose of a city, how we make shade, and different urban design ideas that might be applicable today.

Mina Kim: And it underscores how shade not only cools people down but can also foster community. You wrote about modern-day examples where shade infrastructure has built community.

Sam Bloch: Right. Even in my own neighborhood in New York City — a few weeks ago, late June, first weekend of summer, the school year had just ended. I expected to see lots of people outside celebrating. But the streets and parks were dead. A sticky, early-season heat wave had rolled through.

I took my toddler out for a walk — you can only stay inside with air conditioning for so long — and we passed empty basketball courts, handball courts, and playgrounds. Finally, we found a shady oasis: a courtyard shaded by two 26-story apartment buildings, plus a few London plane trees.

That’s where life was — people playing dominoes, kids scooting, neighbors chatting.

I talk in the book about how shade preserves public space and community life as temperatures rise.

Mina Kim: You have this beautiful line: “They linger and relax, and that engenders more interactions and possibly even stimulates social cohesion. People want to be in shade. They muse longer, pray more peacefully, and find strength to walk farther.”

You also write about how brutal extreme heat is — and I was shocked to learn how many lives it claims compared to other emergencies.

Sam Bloch: Heat is America’s deadliest weather-related killer. The official estimate is around 2,000 deaths per year, but some estimates go up to 10,000. Heat affects the body in many ways — it might trigger a heart attack, worsen diabetes, inflame kidney disease, or set off asthma.

That 2,000-death figure is more than hurricanes, floods, and tornadoes combined. Yet heat doesn’t get the same attention or resources because it rarely causes visible destruction to property. Its imprint is largely invisible — hospital bills, empty streets, people stuck indoors.

Mina Kim: Noelle on Discord writes, “I think we can learn a lot from desert cities in Africa and other civilizations throughout the world.”

Listeners, join the conversation. Do you struggle to find shade in your community? Do you have a story about trying to access shade? What’s your favorite shaded spot? Or maybe you’re an architect or planner who’s worked to include shade.

Email forum@kqed.org. Find us on Discord, Bluesky, Facebook, Instagram, or Threads @kqedforum. Call 866-733-6786.

We’re talking with Sam Bloch, an environmental journalist, about the importance of shade.

You also remind us in the book that it’s not just about how hot it feels — the health effects of sun exposure can be even worse.

Sam Bloch: That’s right. Heat isn’t just air temperature. When we’re outside, we’re getting heat from multiple sources. First, we generate heat internally — especially when exercising or doing physical labor. Then we get heat from the air. Humidity makes it harder to lose heat. Wind can help us lose it.

But perhaps the most significant source is the sun. A microclimate specialist told me to imagine standing in an asphalt parking lot in Phoenix, fully exposed to the sun, on a 105-degree day. The energy from solar radiation is ten times greater than the heat we absorb from the air.

Simply stepping into the shadow of a building or under a dense tree can cut the “daytime heat burden” — the total heat from all sources — by about 30%. That’s huge. Shade can prevent dehydration, headaches, and serious heat illnesses, especially for vulnerable people: children, the elderly, pregnant women, those with chronic health conditions, and outdoor workers.

Mina Kim: Rhishi on Discord writes, “If I look at the Santa Clara Valley from the edges lining it, I see plenty of green. But along main roadways and even some creek trails — no shade.”

Noelle on Discord writes, “Shout-out to the nonprofit Our City Forest in San Jose. They planted a tree between the curb and sidewalk in front of our house in 2011, and it’s doing its job providing shade among other benefits. Walking under trees, the lower temperature is very noticeable.”

We’ll have more with you, listeners, and with Sam Bloch right after the break. Stay with us. You’re listening to Forum. I’m Mina Kim.