How “Green Roofs” Help Save the Planet

In cities across the globe, lush gardens bloom on rooftops. They create a soothing natural retreat, lower temperatures, reduce air pollution, and provide habitats for wildlife.

Replacing dark roof surfaces with gardens can reduce temperatures in cities by as much as 5 degrees, research has found. That's no small matter. The “urban heat island effect” can often make cities 10 degrees warmer than surrounding areas. The green roofs store water in plants. When the moisture evaporates, the natural process cools the air.   

Extreme heat fueled by climate change has proven more deadly than ever. Heat kills 1,300 Americans each year.   

Green roofs have sprouted in cities including New York, Paris, and Singapore. Some countries like France, Switzerland, and Canada have even passed laws requiring new buildings to have at least a partly green rooftop.

That reflects growing awareness of the benefits of green roofs. They do more than just turn down the heat.

Green roofs also: 

• Cut energy use by naturally cooling buildings in the summer. They also retain heat in the winter. 
• Produce oxygen and reduce emissions of greenhouse gasses that fuel climate change.
• Act as a sponge. They reduce runoff that carries pollution when it flows through streets.

So on Earth Day, we salute those helping save the planet by planting on rooftops.  

Photo from US Environmental Protection Agency.