The Dutch city of Utrecht plans to cover every roof in its city district with plants and mosses or solar panels, according to the Guardian.
When city officials say they will cover every roof, they mean more than just buildings — the government has already reportedly installed green roofs on the city’s 316 bus stops.
“In this city district every roof will be either used for green or for solar panels,” Alderman Kees Diepeveen told the Guardian. “It will be that when you look at the different heights, the lower rooftops will be mainly green and the higher ones will be mainly solar panels. And now again a combination of the two because solar panels need some cooling.”
Utrecht also reportedly plans to build a “vertical forest” building that will feature a thousand plants on its sides. Its developers claim it will be able to absorb 5.4 metric tons of carbon dioxide each year, according to the Guardian.
Green roofs provide a number of benefits for cities, including reducing the “heat island” effect — when built-up areas are hotter than nearby rural areas — reducing energy costs, and filtering water. The solar panels in Utrecht will provide carbon-free energy to the city.
Green roof technology is more established in Europe than in North America, according to Green Roofs for Healthy Cities. Stuttgart, in Germany, has been called the “Green Roof Capital of Europe,” and Paris plans to open the world’s largest rooftop farm.
In the United States, cities such as Washington, DC, Newark, New Jersey, and Seattle, Washington, are among the leaders in square footage of green roofs. In 2016, San Francisco passed a law requiring new buildings to devote a portion of their rooftop space to solar panels or green roofs, and a similar law went into effect in New York City in 2019 that requires most new buildings or buildings undergoing major roof reconstruction to devote space to a solar panel, green roof, or combination of the two.
For green roofs to thrive in the US, “those responsible for maintaining buildings may have to acquire new skills, such as landscaping, and in some cases volunteers may be needed to help out,” according to Michael Hardman and Nick Davies, a senior lecturer in urban geography and research fellow, respectively, at the University of Salford.
“Other considerations include installing drainage paths, meeting health and safety requirements, and perhaps allowing access for the public, as well as planning restrictions and disruption from regular activities in and around the buildings during installation,” they added.
As climate change accelerates, it’s vital that cities become more sustainable, which is why achieving sustainable cities and communities is the 11th of the UN's Global Goals for Sustainable Development.