City rooftops are getting a makeover. Instead of concrete, many are now covered by grasses, flowers, and even small trees.

Andy Creath, president of Green Roofs of Colorado, says green roofs are not just pretty. They benefit the climate too.

Creath: “Green roofs actually cool cities.”

By replacing heat-absorbing materials like concrete and tar, green roofs help to lower the temperature of the air around them. And, they act as insulators for buildings, which reduces the energy needed for heating and cooling.

Plus, green roofs absorb water, which helps reduce storm run-off. They can create habitat for birds and pollinators. And in some places, they’re even used to grow vegetables.

Learn more about a new #GreenRoof ordinance that just took effect in Denver.CLICK TO TWEET

In January, a new ordinance took effect in Denver, which requires green roofs on buildings larger than 25,000 square feet. It applies to new construction and older buildings being renovated.

It’s one of the country’s most ambitious green roof mandates, but Creath says Denver is only one of many cities where rooftops are going green.

Creath: “These cities are looking to the future and how they’re going to adapt to climate change, and this is one of the ways of doing it.”

Reporting credit: Anna Moritz/ChavoBart Digital Media.

Jan Ellen Spiegel is a freelance writer and editor based in Connecticut. In 2013, she received a Knight Journalism Fellowship at MIT on energy and climate.