Denver Passes Ordinance Aimed at Curbing Heat Island Effect
The city of Denver, Colorado voted on Tuesday to narrowly pass an ordinance that will require new and some existing high-rise residential and office buildings to have rooftop gardens to help counter the effects of the city’s urban heat island effect.
The final results won’t be released later on this week, but all signs on Wednesday pointed to a close victory for the pro-ordinance group, which is designed to stop the city’s urban heat island.
Denver’s heat island is among the highest in the country, according to a 2014 Climate Central study, with an urban-rural temperature differential of 4.9° between the city’s center and outlying rural areas. A heat island is the creation of additional warmth in a city due to the additional pavement and concrete in urban areas. Simply put, pavement absorbs and ‘traps’ in heat, leading to warmer temperatures in those areas.
This ordinance aims to curb some of those impacts by requiring new buildings to have varying sizes of rooftop gardens, with the idea that those gardens will reduce the surface area of pavement and help mitigate the urban-rural temperature split.
The ordinance will be the strictest in the country, and it would be modeled after Toronto, Canada’s strict green roof bylaws, which were put into law in 2012. San Francisco, California enacted similarly stringent laws earlier this year, but Denver’s will require more space to be covered than San Francisco’s.
WeatherNation will have more on this.
For WeatherNation: Meteorologist Chris Bianchi