The Future City and Climate: What We Can Do About the Heat
When we talk about climate change, people sort themselves into tribes: the deniers, the skeptics, the technocratic scientists, the holier-than-thou environmentalists, the doomsayers… Then there are the people like us. We worry that something we don’t fully understand is happening. We remember when winter in Minnesota meant snow on the ground, and when extreme weather events didn’t happen quite so frequently—yet we cannot wrap our heads around what the future might hold for us, or how we can avoid or even prepare for it. It is to this middle crowd that urban climate change researcher Brian Stone addresses his book, The City and the Coming Climate: Climate Change in the Places We Live. If you want to understand climate change, and how you as an urban dweller have the power to make a difference, read the book.
Stone discusses the basic building blocks of climate change, but focuses on its impact on cities. Stone cites this powerful statistic: If the average temperature of the earth rises by 2 degrees Celsius (or when, rather—we’re well on our way), cities will see their temperatures rise by up to 8 degrees Fahrenheit. Warm days will become hot days and hot days unbearable. Higher temperatures will increase air pollution and heat exhaustion among urban dwellers. In 2003, he notes, an extended heat wave killed 70,000 Europeans, mostly in overheated cities.
Many efforts to address climate change on a global scale focus on reducing carbon emissions. Stone points to actions that cities can take to address overheating on the urban scale, the scale at which we live. For example, we can plant trees for shade and install raingardens that cool the ground. These actions, focusing on green space, can keep our cities safer and more habitable, and help decrease global temperatures.
Stone explains how cities become urban heat islands. Plants shade the ground and cool their surroundings through transpiration. But in cities, which have limited green space, dark and dense building materials soak up and retain the heat from the sun, turning urban areas into “islands” of heat in the relatively cooler rural areas around them. This can influence weather patterns. The extra heat rising off the urban landscape can increase convection within storms, pushing them higher faster, sometimes causing them to bypass the city altogether.
When it does rain, our cities are designed to send runoff to the nearest storm sewer. This prevents storm water from soaking in and cooling the earth and in turn being cooled itself. Water does not get into the ground. Stone points to the loss of tree and plant life as the number one reason that cities become so hot. We’ve lost shade, nature’s umbrellas and air detoxifiers, and because of that we’ve lost water. He advocates for more plants and trees in cities to help address the problem.
There are many ways to do this. Some are more complicated, such as green roofs and walls that house vegetation and plant life. These examples of “ecological urbanism” provide shade and absorb heat. Other strategies include installing raingardens, swales, and stormwater planters to mitigate runoff and heat. Native plants in your garden and permeable pavers in your driveway will help decrease runoff and infiltrate rainwater into the ground.
Planting trees increases the moisture in your yard. Their shade keeps buildings cool in the summer, and can reduce wind, and consequently home heating costs, in the winter. Research shows a neighborhood with mature trees can be 4 to 8 degrees cooler than its treeless counterparts, and the immediate shade of a tree can be 20 degrees cooler. As the old proverb says, “the best time to plant a tree was 20 years ago; the second-best time is today.”
Stone says we don’t live on the global scale as individuals. But we can have an impact on our own local climate. What you do about your microclimate, what flowers and plants you choose, what grasses you grow, what pavement you use, how many trees you plant—these are all decisions you control. And improving the microclimate of your own yard contributes to a larger effort.
Break ground in your neighborhood. Join thousands of others who are pledging to plant 10,000 plantings by 2020 and creating green space in their neighborhoods.
To help you get started, connect with any of our Blue Thumb partners for ideas on increasing your property’s green factor.
The City and the Coming Climate: Climate Change in the Places We Live, by Brian Stone, Cambridge University Press, 2012.
Related Climate Stories and Urban Cooling Methods:
Georgia Institute of Technology: School of City and Regional Planning. “Brian Stone.”
Huttner, P. (2017). “Climate cast: The warming of MN forests and lakes.” MPR News.
Minnesota Pollution Control Agency. (2017). “MS4 fact sheet – green roofs.”
United States Environmental Protection Agency. (2016). “Heat island cooling strategies.”
United States Environmental Protection Agency. (2017). “Learn about heat islands.”