According to Wikipedia, Green Infrastructure is defined as a way of building with nature to solve urban and climatic challenges. The main components of this approach include stormwater management, climate adaptation, reduction of heat stress, increased biodiversity, food production, better air quality, sustainable energy production, clean water and healthy soils, as well as improved quality of life through recreation, shade and shelter in and around towns and cities.
Significant elements of Green Infrastructure are green roofs, living walls and rainwater harvesting. The Foundation for a Green Future, Inc. is a staunch propoent of green roof technology.
A green roof, sometimes known as a living roof, is a roof covered in living vegetation. Green roofs can include sod, vegetable gardens, decorative plants, and even small trees. In the summer, a layer of vegetation on a building’s roof can reduce a building’s total energy consumption by reducing the amount of heat that is absorbed while air conditioners are running. Amazingly, green roofs can also reduce energy consumption in the winter by decreasing heat loss and evaporative cooling. Green roofs can filter contaminants out of the air, creating a safer city environment with lower rates of asthma. A green roof can also collect and filter rainwater, turning water that might otherwise have been wasted into a fresh, clean resource. Some green roofs can be equipped with safety fences so that children can play in a natural environment even in a densely populated city.
Another option for greening our urban environment is a living wall, also known as a green wall. A living wall can be made of a façade of climbing plants like ivy or melon, or a mat of growing medium that can support smaller plants. Living walls can reduce energy consumption by cooling and insulating buildings. A living wall can also filter air and water to create a healthier, cleaner environment.
Foundation for a Green Future, Inc. runs educational workshops and designs interactive curricula about green roofs, living walls, urban gardening, and more.
By Karen L. Weber
Just shy of a month ago, the annual Green Roof for Healthy Cities Conference took place in Baltimore, MD. Two years ago it was here in Boston. Much has happened since. In 2007 there was an estimated 30% gain from 2006 in the square footage of green roofs in North America Now the figure has jumped to 2,407,525 square feet according to the survey of Green Roofs for Healthy Cities – a gain of 40% for extensive green roofs. However, the majority are in the Midwest, although Phildelphia and Washington ,DC are now on the US top ten cities list for green roofs. We need to work on Boston!
Green roofs are a good thing to install any and everywhere, but the most important impact is along our coasts where our urban centers are cement ovens emitting great amounts of heat into our atmosphere.
It has been seen that conventional roofs can get as hot as 150-200ºF. Almost hot enough to fry an egg! And we all know that when we are barefoot in the summer we jump from the hot black asphalt to the cool green grass. This is because vegetation tends to remain between 77-90ºF. That large mass of hot air rises over our coastal cities and settles down over our coastal waters.
There is a constant exchange between the land and water. The hotter the air over the land, the warmer the air is over the ocean. This is likely impacting our fisheries and our coastal currents. Do you know that the slightest rise in our ocean temperature is a signal for jellyfish to move in? Once jellyfish move in to a fishery they can overtake the fishery and turn it into a desert since they have virtually no predators.
Roslindale already experienced its first blackout this year and it was not yet summer. Do we know what is in store for us? If we have more heat waves, we will have more blackouts where people will be without airconditioning and fans to keep them cool. This puts young children and elderly at risk.
In Chicago in 1995 there was a heatwave that killed 785 people. Two years ago there was a terrible heatwave in France and Spain in which they estimate 20,000-30,000 people died. Mayor Daley has been making a dramatic effort to cover Chicago in green roofs to help protect the city from the heat.
Europe, particularly Germany , has been working for more than 50 years to put green roofs on their buildings. There is an incredible impact green roofs have on the peak demand that we experience in a heatwave when everyone puts their aircooling systems to the highest notch on the knob. Green roofs can bring our knobs down! They can also reduce our need to build costly power plants to supply electricity for a few weeks in the summer to cover our short but critical peak demand.
Let us install more green roofs to make our cities healthy. We will have more beautiful places to live and we will stay cool. And we can keep our hands off our A/C knobs….