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Just as population pressures in cities compel us to build upwards, so resource scarcity has given rise to the concept of green roofs and other forms of urban greening. Many European cities are already investing in green roof technology, and North America is not far behind. An expert panel in Singapore has gone so far as to recommend that building owners be required by law to install green roofs.
Singapore has gone so far as to recommend that building owners be required by law to install green roofs.
This trend has grown out of an increasing understanding of urban water issues, coupled with a series of economic considerations. More and more cities are giving renewed thought to the issue of stormwater management, many having recently been struck by climate change-related floods or water shortages. Green roofs reduce stormwater runoff, easing pressure on existing sewer systems.
On the economic side of the ledger, green roofs increase the energy efficiency of the building on which they sit, which translates into considerable cost-savings over the lifetime of a roof. Building owners are finding that green upgrades to existing buildings provide a worthwhile return in increased rents, sales and property values, in addition to more intangible benefits such as lower employee turnover.
The question of whether environmental sustainability must come at an economic cost has raged for years. That green roofs satisfy both criteria, and have been adopted for such a wide array of reasons, suggests that this trend is likely to gather momentum as long as resource scarcity and economic well-being are on our collective minds.
While black roofs trap heat, contributing to global warming, vegetation absorbs it, thus cooling its surroundings. Further, a large green roof can reduce the energy demand for air conditioning by more than 75%, resulting in a correspondingly large financial benefit. The appeal of making considerable energy efficiency gains without any sacrifice – since roofs are typically unused space – has had a role to play in the unopposed adoptation of these urban green spaces.
Due to the myriad benefits, green roofing may become the standard for new construction projects. Employers and landlords may also find that their employees and tenants increasingly come to expect rooftop gardens at their disposal.
By Stu Campana
Stu is an international environmental consultant, currently working with Fern Ridge Landscaping and Eco-Consulting in Ontario, Canada. He has a multi-disciplinary background, with a BA in Political Science and an MSc. in Environment and Resource Management from the Vrije Universiteit in Amsterdam. Stu is interested in the manifestation of climate change as a social and political issue, and in the future impacts of these complex problems.