The accelerated growth of modern cities has affected many of the planet’s natural processes. In urban centres, which are dominated by asphalt and cement, have been shown to actually alter the natural cycles of water and air among other things.
During the summer, urban regions tend to have temperatures that average one to 4.5 degrees Celsius higher than in nearby areas, a phenomenon known as the heat island effect, with the heat increase varying based on the climate, topography and urban design.
New York City, for example, is 3.6 to 5.4 degrees warmer than its surrounding suburbs. The effect is more pronounced in tropical cities. In Mexico City, the temperature difference between the city and its suburbs can climb as high as nine degrees.
To restore the balance in urban ecosystems, urban planners and designers have started to look for different ways to generate green spaces in an increasingly grey world. Green spaces benefit cities and their inhabitants by minimizing temperature variation, absorbing rainwater, reducing stormwater runoff and promoting biodiversity, all of which can improve the well-being of the cities inhabitants.
Indeed, green roofs have become very popular in many regions over the last decade, but this phenomenon is still not taking hold in some parts of the world. In Latin America, for instance, there are only a select few cities benefiting from the introduction of green roofs as countries such as Argentina, Chile, Brazil and Colombia, there is no legislation encouraging or enforcing sustainable building requirements.
The City of Buenos Aires, Argentina, took a big step last month by approving the Green Roofs Law. The law will grant building owners a reduction in service-related costs such as lighting, sweeping and cleaning to help offset the cost of integrating green roofing in the building design. That means that those who install and maintain green roofs on their buildings will be able to help reduce greenhouse gases in the busy city without paying wholly out of their own pockets.
The law aims to promote sustainable features for both new and existing buildings, helping to reduce the “heat island effect” and improving air quality within the city limits. The roofs must be built to specific building standards using specified materials, including a hydrophobic insulating membrane and a protective pre-coating layer of drainage gravel. Every building must also undergo a structural analysis to verify the load resistances generated.
Developers looking to implement green roofs must deal with the evolving availability of materials in Latin America. The law provides an important incentive to encourage developers to invest in materials that, although far more expensive initially, can help to reduce the servicerelated building costs in the longer term.
Buenos Aires’ Green Roof Law is a significant step towards promoting a healthier and more sustainable city and big a step forward for sustainable design in Latin America.
The importance of encouraging sustainable development in Latin America should not be underestimated. Australia and Argentina are already linked by the drought cycles of the el nino/la nina phenomenon, and with climate change a growing concern, what happens on one side of the world will eventually be felt on the other.