“With Death of Forests, a Loss of Key Climate Protectors,” read a recent New York Times headline for an article about how killing forests heats the world. We can see climate change all around us. The Department of Agriculture’s 1990 map of climatic zones for plant hardiness placed most of New Jersey and all of southeastern New York in Zone 6. As of 2007, warmer winters have made the entire region on average 10 degrees hotter, shifting the area to zone 7. Temperatures have risen in Connecticut, too: One can now grow bananas in the Nutmeg State.
As a designer of major urban landscape projects in such disparate climates as Texas, Spain, India, and China, I have observed that no city, whether we’re speaking of governments or citizens, has found a way to deal with climate change, even though shifting weather has consequences across the globe. Government has failed us. With a few exceptions–Mayor Michael Bloomberg and his green program, PlaNYC 2030 being one of them–politicians are paralyzed. In short, they have not put into action ways of addressing cities that can be understood by the people who live in them.
And yet cities are the prmary drivers climate change. They are heat islands. The sun heats roofs and streets 50–70º F hotter than the air temperature. Rain runs off pavements. Urban pollution washes into rivers and streams. River edges erode. Communities flood. And cities keep growing: In 1995, 50% of the world lived in cities. In 2025, it will be 60%. Much of this growth is in developing countries, where little is being done to prevent pollution, which further compounds climate change. The stakes are clear, but misinformation abounds. Radical change requires radical solutions, which in this case, are surprisingly easy to implement. Given our present situation we need to take actions as citizens, each one on the basis of their specific abilities. These are my suggestions.
The industrial lawn, staple tableau of the American Dream, is actually a toxic field of conformity that poisons everything around it. It consists of two or three species of grass, which are fertilized with nitrogen and phosphorus, and sprayed with herbicides. Rainwater washes these chemicals into groundwater and rivers. Algae blooms; fish, insects, and plants die.
By contrast, what I would call a Freedom Lawn is composed of a diverse mix of grasses and wildflowers and includes clover, to to fertilize the lawn without chemicals. Polluting runoff is eliminated. The rich plant mix fosters worms, butterflies, and birds.
Bare apartment and office roofs reflect the sun. Over a 24-hour period, temperatures can fluctuate by 180 degrees. Hot winds drive dust and dirt into the air. During storms, roofs send polluted rainwater into the drainage system, and sewage can overflow.
But rooftop deserts can bloom into oases. Green roofs absorb 90% of the sun’s energy. Rooftop plants filter dust and dirt, and evapotranspiration returns up to a third of the rainfall to the air. Roof temperatures drop, air conditioning use is reduced, and roof life doubles.
New developments around cities increase the volume of water to be drained. Underground pipes send the drainage water straight to rivers and streams, carrying surface pollution. As a result, big storms cause floods and make sewers overflow. Surface drainage systems, like the one in Minneapolis illustrated above, reduce runoff by retaining water at the peak of storms and averting floods. In addition to providing parkland, the plants on the banks and in the stream clean the water before it enters into ground- or river water.
These designs are available today. They have been tested, and they achieve results. In partnership with landscape architects and bioengineers, we, as citizens of cities and the world, must advocate for change. Any one of us can plant a Freedom Lawn, thereby eliminating chemicals and reducing runoff. Any one of us can start a green roof, making the city cooler, cleaning the air, and stemming runoff. With a few allies, we can go further, reaching out to neighborhoods and entire cities, and constructing ways for nature and humanity to thrive and co-exist in a better, sustainable world.