Michigan is sweating through its fifth-warmest July in a century. Detroit and other local cities have designated libraries and other public facilities as “cooling centers” where residents can take refuge from temperatures in the mid-90s. Unfortunately, the long-term forecast offers little hope of a respite. Scientists predict that global warming could triple the number of hot days in Detroit, posing a particular threat to the city’s elderly residents.
UniverCities Connection intern Stephanie Chueh has been researching one climate change mitigation strategy that promises relief to the sweltering streets: shade trees.
Trees inhale some carbon dioxide through their leaves, but that‘s not their only climate benefit. By sheltering adjacent buildings from the sun, they can cut down on the use of air conditioning and reduce electricity consumption. In that sense, they serve as both a climate change mitigation and adaptation strategy, not only curbing climate change but lightening the global warming burden that we will have to bear. “I love it when things are multifunctional!” Stephanie says.
According to her research, the average street tree costs the famously leafy City of Ann Arbor something like $250, plus $30 annually in maintenance. The City calculates the estimated yearly energy savings per tree at $47.55. That’s a darn good deal, especially considering the benefits of trees for the human environment. A green canopy makes for more comfort, natural beauty, and higher real estate values, too, suggesting why new tree plantings are so often a part of streetscape improvement plans in cities’ business districts.
Ideally, Stephanie indicates, tree planting would be just one element in a suite of climate strategies applied to city streets. “A bunch of projects can work together and serve different purposes,” she says. “For example, just building more sidewalks by themselves may not reduce a ton of GHG [greenhouse gas] emissions, but coupled with LED streetlights that light the way and trees to shade pedestrians, we can begin to take more cars off the road and build more vibrant, livable communities.” After all, what’s a cool city if not a comfortable place to chill?