Green Cities –The Escape from the "Heat Island"

In post-apocalyptic science fiction (or present day Chernobyl), Mother Nature is often depicted as having 'taken back' the cities of mankind: all is quiet, a deer nibbles among buildings with shattered windows and crumbling walls. Weeds, grasses and flowers have begun to grow upon the rubble and the roofs of remaining structures. Alternately, to evoke travel through time, fingersnaps exchange skyscrapers and streets for soaring redwoods and mossy earth, or vice versa.

But why should dense urban centers be a one-or-the-other proposition, with endless concrete and a few token parks thrown in? When Renzo Piano designed the new California Academy of Sciences building in San Francisco's Golden Gate Park, thought to be the 'greenest museum ever built', he wanted it to seem as though a piece of the park had been lifted and the building 'slid underneath'. Granted, you're in a park to begin with, but isn't that exactly where 99% of North American cities were plunked down in the first place? Fields, forests and wetlands-- even swamps, as if doesn't say in the Welcome to D.C. visitor's guide.

Viewed from above, urban roofs are essentially inanimate: repeating rectangular tracts of grey sandpaper, pocked with steel boxes containing elevator motors and chugging ventilation equipment. Calling this space 'wasted' and idealistically demanding organic tomatoes and rosemary be nurtured atop the 77th floor? As far as single urban core projects go, that's still the legal prerogative of the builders (at present only Germany, Switzerland and Japan require vegetation atop various new buildings). However, a long day's sunlight shining down upon a 20th century style metropolis results in something called the 'urban heat island effect', which could be dramatically reduced by living roofs. Absorption of rainwater is another benefit, as storm runoff necessitates bigger and bigger drainage systems and increasing time spent maintaining them.

When Disneyland updated its Tomorrowland in 1997, it was asserted that the Future was 'looking more and more like Montana'. The Autopia attraction persists (and to be fair, there are plenty of freeways in the Big Sky state), but the point was valid: people in the 1950's saw a future where we lived completely removed from trees and wildlife. In the Fabulous Year 2007 you can look down upon projects under construction that buck old trends-- maybe not from a flying car, but from a blimp advertising tires that could end up on electric ones, perhaps.  On the west coast of North America alone, the 2.5 acre, 1.7 million native plant accommodating living roof of Cal-Sciences is just one example of cities and nature shaking hands. In Seattle's Ballard district, a new library's roof is home to 18,000 low-water plants (appropriate... Ballard is historically-Norwegian, and the Vikings often covered the tops of their homes with turf). On an even more ambitious scale, when the Vancouver, B.C.'s convention center's expansion is completed next year, the building will feature a six-acre living roof-- the largest in all of Canada. It will be home to 400,000 plants and feature wild grasses sure to be appreciated by wildlife visiting downtown Vancouver's north shore.

Cooling down huge cities by a few degrees won't solve global warming... helping migratory butterflies won't bring back extinct species... rooftop produce gardens won't significantly affect freeways jammed with countless semi trucks trying to keep fast-food chains filled... but as steps are slowly taken towards a more sustainable world, science will be right alongside with designs that may not resemble the tomorrow we expected, but will help ensure there actually is a tomorrow.

by Eric Duby

links:
vcec.ca
calacademy.org
pressureworks.org

Comments

[jtnewsom]

Arizona gets hot. My garden wall at 1 am was still hot to the touch. In fact four months of the year my back yard was no man's land 24/7. What to do?

I grew some cat claw vines on those walls and found my back yard turn completely around. It became a haven for every kind of urban wild life in our area. The wall stayed cool night and day.

Get others to try it with this kind of proof. Hell no! Everybody either has their head up their asses or they want to kill the planet on purpose.

[Eric Duby]

Here's a trick: go to your nearest botanical garden, and pretend you've got a cabin there, just out of sight. I've been mentally living in San Francisco's for years. Our pet peeve? Neighbors who water in the blaring Noon sun, arcing water up into the dry air...