In the climate crisis, a vision of Shade Cities

© Steve Austin (used with permission)

By Steve Austin, JD | ASLA | Assistant Clinical Professor of Landscape Architecture, Washington State University

A heat wave unlike any other has begun in the U.S.  This is the long-term heat wave accompanying the accelerating climate crisis, which is caused primarily by the burning of fossil fuels.  Global heating is happening, despite presidential claims that it’s a Chinese hoax, despite fossil fuel companies’ best efforts to confuse, and despite many people’s resulting disinterest.  Regardless and urgently, in the face of reality, we need to create “Shade Cities” to ensure urban livability over the coming decades. 

It is getting hotter, faster. Industrial civilization has already raised the average global temperature by 1.8 degrees Fahrenheit above historical levels.  Eighteen of the last nineteen years have been the hottest on record, and the heating over the past four years has been “exceptional.” July 2019 was the hottest month ever recorded. This added heat is altering the Earth’s climate system with devastating impacts.

This is happening right now. Unless we stop burning fossil fuels very soon, the future will be even hotter.  

If we don’t stop burning fossil fuels, reasonable estimates are that average daily summer temperatures in US cities could increase by seven degrees or more over the next 50 years. This is obviously well within the lifetime of people alive today.  Extremely hot days – those with a heat index above 100 degrees – will also increase.  New research suggests that by mid-century, more than 250 U.S. cities will experience thirty days or more per year above that mark in a typical summer, compared to just 29 US cities historically.  

Exacerbating this, the urban heat island effect can additionally increase temperatures more than 20 degrees above those air temperatures, particularly after sunset.  The bottom line is that even “normal” summers will become incredibly hot.   “The rise in days with extreme heat will change life as we know it,” says Rachel Licker of the Union of Concerned Scientists. 

This will impact the country in many negative ways.   First and foremost, this is a looming health emergency, especially for vulnerable populations of youth, elderly, outdoor workers, the unsheltered, and those without access to cooling.  This heat wave will also continue to erode our already crumbling infrastructure.  Further, dealing with extreme heat will cost businesses and individuals money, further stressing economic and social conditions.

Unfortunately, cities in the U.S. do not appear to be anticipating either the heat wave or the associated impacts.  So much needs to be done, from new city planning paradigms, to connecting vulnerable populations with improved social and health services, to ensuring the reliability of the electric grids. 

Fortunately, there is one basic action that can help us adapt to the hotter reality:  planting trees. By starting to plant trees now, and absolutely everywhere possible, they will be mature when the heat wave reaches new extremes. 

Planting trees creates multiple victories for U.S. cities. Trees improve air quality, add beauty, and sequester carbon, which will be vital in restoring a livable atmospheric CO2 balance. They also filter and slow rainfall runoff, which will increase in amount and intensity in a hotter world; trees can help to reduce the impact of flash floods. Most importantly for the heat wave, trees will provide shade. New research shows that cities with robust urban forests are cooler by as much as 10 degrees Fahrenheit. 

Access to this shade in the increasingly hot time will be a social justice issue.   Poorer neighborhoods generally have much less tree cover than their wealthier neighbors. Lack of shade must not become another indicator of inequality in our communities:  access to it will be as vital as access to water and health care.  

In acknowledgment of the crisis, communities should begin developing “Shade City” plans to plant billions of trees in American cities.  This is beyond anything ever attempted in U.S. urban planning and will change everything about how planning is now done. From now on, one of the first questions of city planning should be:  “what about the trees?” Crucially, these plans should focus on creating diverse urban forests with climate appropriate trees and not simply a monoculture.  Trees should be planted in parks and around schools, churches and hospitals, factories and streams, along streets and trails, and in so many other places.  Much of the 25 to 40% of urban areas made of pavement and parking lots should be ripped up to make way for trees.  And of course every single homeowner should add to the forest. 

To accomplish the Shade City vision, a long-term sense of institutional and personal stewardship is needed, as is funding for planting and maintenance. This stewardship will mark a vital step toward repairing our relationship with the rest of nature.  Positively too, this is economic development in the climate emergency era– think tree nurseries – as well as a job creation opportunity: imagine a Shade City Corps, modeled on the Civilian Conservation Corps, to plant and maintain trees as part of the Green New Deal. 

Shade Cities can be our gift to the future.  And even if a disbelief in the climate crisis is central to your dream of making the U.S. great again, please help plant trees, just in case. The climate crisis isn’t stopping simply because you wear a red hat.  That’s not throwing shade, that’s pleading for some. 

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