On a typical summer's day, the roof covering the Minneapolis Target Center -- home to the NBA Minnesota Timberwolves -- regularly reaches temperatures in excess of 140 degrees. Thanks to a new $5.3 million green roof installation, such blistering conditions will come to an end. The nearly 2.5 acres of plants will maintain roughly the same temperature as the air, reducing cooling and heating costs.

Billed by project managers as the fifth-largest green roof project in the United States, the Target Center will also keep an estimated 3.68 million gallons of rainwater annually from draining into the Mississippi. Workers started in late June unrolling 900 rolls of 80-pound vegetation mats -- containing about 2.5 inches of soil -- across the 110,000 square foot roof. Almost 11 miles of irrigation lines will be installed and concrete pavers to offer firebreaks "just in case".

"It's really depressing to see the sheer amount of tarred rooftops," said Minneapolis City Council Member Lisa Goodman. "This is an opportunity."

The city is also taking the initiative on planning for what may amount to the largest solar-electric array in the Upper Midwest. If the city can find a partner, Goodman says, the array will find a home atop the Minneapolis Convention Center.

With Toronto recently passing a new law mandating "green" rooftops for all new developments, and Chicago installing more than 600 green rooftops, don't be surprised if similar initiatives take off around the country. As Minneapolis has discovered, there's plenty of real estate above our heads to exploit for the greater green good.

Check out a video below of crews starting work on the new green roof project in Minneapolis. The project is expected to be completed this fall.