“Not only can we stop damaging nature, but we can also restore, it, too. And when you put the two together, you get powerful and natural solutions to climate change.”

~ Bronson Griscom

“We need bees for the future of our cities and urban living.”

~ Noah Wilson-Rich

Envision downtown Denver before it was developed: gentle hills, cottonwoods and wild plum along the streams feeding into the Platte River, wide grasslands interspersed with sage and rabbitbrush. Of course, we’ve now taken most of that ecology and covered it with buildings and pavement. But maybe, we can take some small steps to bring the natural areas back.

Denver just approved an initiative to require “green roofs” for certain new and renovated buildings. The roof modifications can include a traditional vegetation cover or solar panels. The Denver Green Roof Initiative proclaims that “green roofs and solar work in tandem. Solar panels give shade to vegetation and the plants keep the roof cooler.”

In addition, “The benefits are many! Green Roofs are a Best Management Practice for storm water management. They reduce the Urban Heat Island Effect through evapotranspiration. This also reduces energy costs. Air quality is improved and noise pollution is lessened. Roof longevity is extended. City beautification is achieved which, studies show, lead to a better quality of life and workplace environment.” Given that Denver is the eighth-worst city in the U.S. for ozone pollution according to the American Lung Association, anything done to improve air quality also has significant health effects.

Arguments against the green roof requirement focused on the costs, primarily the initial capital costs. Proponents noted research that showed green roofs last longer and had lower operating costs than normal roofs, mitigating the capital costs over time, usually within five years.

However, the benefits of vegetative green roofs are not limited to us humans. Increased vegetation in densly urban areas provides habitat for other creatures, including birds and insects. Of note, urban vegetation is known to be beneficial to bees. Janet Marinelli reports that “…researchers are finding that flower patches — in parks, residential properties, community vegetable plots, and vacant lots — support surprisingly healthy populations of bees, the most important pollinators in agricultural and most natural areas. In a few cases, urban bee populations are more diverse and abundant than those outside the city.”

Many cities, including Denver, are located on riparian corridors (major rivers) that provide the habitat needed for insect and bird migration routes. While much has been made of bird disorientation and deaths associated with night-time lighted tall buildings, vegetative roofs provide both shelter and feeding opportunities for birds and insects.

People like nature – they feed pigeons in cities, and cameras fixed on peregrine falcon nests on skyscrapers have always attracted ardent followers. Bringing nature a little closer into the urban experience is calming and beneficial to our health. Employees value the quality of the work environment, so provding access to nature would seem to be highly desirable feature for most work places.

Although some people are nervous around bees, including those with an allergic reaction to stings, Noah Wilson-Rich maintains, “If you’re not a flower, these bees do not care about you.” Most of us, though, enjoy the buzzing of bees as they collect pollen and spread it to other flowers. Some places actually maintain bee hives in their roof gardens and collect the honey for use and promotional purposes.

Researchers also note that revegetation of denuded areas can have a positive effect on climate change. It follows that covering rooftops with vegetation, and even green walls, will help. So, in addition to all the other benefits, green roofs help to mitigate some of the climate change impacts.

Maybe the Denver initiative isn’t world changing by itself, but it seems like a relatively practical step in the right direction, providing benefits across mutiple factors. But, it doesn’t take big steps to achieve big change; many small steps can accomplish the same. As the Pollinator Partnership’s Vicki Wojcik points out,

“If everyone in a city of a million people planted even one pollinator-friendly plant,” she says, “there would be a million more foraging opportunities for bees.”

Bee green!

Additional Information:

American Lung Association, State Of The Air 2016, Lung.Org

denvergreenroof.org, The Denver Green Roof Initiative, 2017

Janet Marinelli, Urban Refuge: How Cities Can Help Rebuild Declining Bee Populations, November 9, 2017, YaleEnvironment360

Justine E. Hausheer, New Science Shows Nature’s Potential to Fight Climate Change, November 7, 2017, Cool Green Science

Noah Wilson-Rich, Every City Needs Healthy Honeybees, July 2012, www.TedTalks.com