How Chicago is going green to battle oppressive heat

How Chicago keeps cool
How Chicago keeps cool 02:30

Dangerous heat and humidity will scorch several areas of the country Friday. Temperatures in cities across the central and Southern states could rise into the triple digits, and excessive heat alerts are posted in 21 states from coast to coast.

More than 150 million people will struggle with oppressive temperatures as the so-called "heat dome" moves east.

Dangerous heat wave 02:10

In Texas, the brutal sun caused the highway to buckle, and in Madison, Wisconsin, school district officials had to cancel summer school.

And in Chicago, firefighters have been put on 10 to 15-minute rotations to prevent overheating. The city is trying to do its part to bring the temperature down.

In Chicago, the answer to bringing down the temperature may be looking up, reports CBS News correspondent Dean Reynolds.

"So this little lot of grass is probably doing a little bit of cooling for the Prudential building," said Chicago's former Chief Sustainability Officer Karen Weigert.

According to Weigert -- now a senior fellow on global cities at the Chicago Council on Global Affairs -- darker surfaces like concrete and asphalt retain the high temperatures, turning major metro areas into so-called "heat islands."

"And so in the day, the heat is absorbed and then it's often actually released at night, so in day and night you end up with a hotter environment than if you move out a little more where you've got more trees, more green."

Weigert said Chicago's more than 500 green rooftops help repel heat and provide shade.

"It's staying away from situations where all the vegetation has been removed because then you got no counter-balancing," Weigert said.

Chicagoans know better than to take the heat lightly -- another summer wave struck the city 21 years ago, killing more than 700 people.

"So you're seeing more and more heat waves, more and more heat in general. And so cities on multiple continents are asking these same kind of questions," Weigert said.

Forecasters are actually calling this stretch of high temperatures a "heat dome" that's spanning the country. Temperatures in New York and Washington, D.C. are expected to reach well into the 90s this weekend. But the humidity may make it feel more like 100.