A single block in Chelsea, Mass., may offer a template for cities looking at what works — or doesn't — to cope with longer, hotter summers because of the warming climate.

Boston area city blocks become test cases for beating urban heat Boston — For Arwa Ait-Chaib and her mother, Wafa El Hidar, summertime in Chelsea, Massachusetts, means trying to beat the heat.

In what it calls an "urban laboratory," GreenRoots has planted more than 100 trees on the block, resurfaced the street in lighter colors to reflect heat, and painted nearby rooftops white.

An intensive effort is underway to lower temperatures on one of the hottest blocks in Massachusetts. The Cool Block pilot includes 47 new trees. Dark pavement will become gray or white.

Boston's hottest city blocks can see summer temperatures up to 10-12 degrees Fahrenheit warmer than other parts of the city. Painting flat, black roofs white could significantly cool the area.

In what it calls an "urban laboratory," GreenRoots has planted more than 100 trees on the block, resurfaced the street in lighter colors to reflect heat, and painted nearby rooftops white.