Every year, four billion tons of cement are manufactured—a half ton for every person on Earth. Its production contributes to greenhouse gases, making our cities even hotter.

There’s a song I think of every July. It’s titled “Summer in the City,” and it was recorded by The Lovin’ Spoonful way back in 1966. Some of the lyrics go like this:

“Hot town, summer in the city
Back of my neck getting dirty and gritty
Been down, isn’t it a pity
Doesn’t seem to be a shadow in the city
All around, people looking half dead
Walking on the sidewalk, hotter than a match head.”

I have thought of that song every July for the past decade or so, I think, because every year, the summers in the U.S. have been getting hotter and hotter—especially in our cities. Part of the reason for that is the urban heat island effect, where roof and pavement surface temperatures can be 50 to 90 degrees Fahrenheit hotter than the air. Shaded or moist surfaces—often in more rural surroundings—remain close to air temperatures. And, according to the Environmental Protection Agency, air temperatures in cities, particularly after sunset, can be as much as 22 degrees Fahrenheit warmer than the air in neighboring, less developed regions.


Every year, it seems, summers get hotter—especially in our cities. Reminds me of a 1966 Lovin’ Spoonful song.

Cities also tend to have less trees and vegetation than rural areas, with concrete bridges, dams, highways, sidewalks and buildings taking their place. In fact, cement (which is the glue that allows concrete to harden) has been called “the foundation of modern civilization.” Worldwide, four billion tons of cement are manufactured each year—a half ton for every person on Earth, and it has a huge carbon footprint.

That’s why Ferrock offers hope for our hot cities. Ferrock is a waste-iron-based, glass-aggregate cement. Its whole manufacturing process is carbon negative: it not only keeps more of the greenhouse gas carbon dioxide from entering the atmosphere but actually takes some of it out.

Watch the video from the PBS NewsHour below, which demonstrates the advantages of using Ferrock in building our cities. It isn’t available for large projects just yet, such as an airport runway or a six-lane highway. And, it’s not quite as exciting and beautiful as the forested city China is currently constructing.

Cement accounts for about 5 percent of global carbon dioxide (CO2) emissions. ©Valerie Everett, flickr

But it’s good to know that perhaps in the near future, instead of contributing to greenhouse gases and even hotter summer temperatures, our cities could actually use up and trap CO2.

As for “walking on the sidewalk hotter than a match head,” I’d rather walk on sequestered CO2.

Wouldn’t you?

Here’s to finding your true places and natural habitats,