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Tuesday, December 04, 2018

American architects are looking at ways that urban design and planning needs to adapt to coming temperature shifts

A study looked at how an increase in the number of “dangerous summer days” will increase the number of heat-related deaths in 45 U.S. cities. An estimated 150 Americans will die every summer day due to extreme heat by 2040, with almost 30,000 heat-related deaths annually. That’s twice the number of people who are killed by gun violence annually in the U.S. today.

American architects are looking at ways that urban design and planning needs to adapt to coming temperature shifts.

The large majority of urban heat island effects are accruing as a result of the replacement of natural systems or living systems with hard surfaces and engineered surfaces." That, of course, is the overall story of climate change. But cities face a particularly difficult challenge when it comes to cooling, since many of the natural remedies have been eliminated thanks to dense construction and the growth of air conditioning, which by consuming ever-increasing amounts of energy that generates the emissions responsible for climate change, creates a negative feedback loop. For those who can afford it, technology is creating an indoor ecosystem and car-focused transportation network dependent on artificial cooling.

The biggest effect has been going from building design that emphasizes cross-ventilation to those with tight insulation. But it seems like everything that involves air conditioning has created undesirable feedback loops. There’s no way modern traffic systems, and our huge traffic jams, would be bearable without air conditioning. And one effect of artificial cooling is you’re able to pack more concrete, stone, steel and asphalt into a small area, and you have the urban heat island effect.

Manhattan offers a case study in how technology meant to cool ends up making us hotter in the long run: the dense development of modern high-rises, made possible by air conditioning, creates strips of concrete and steel that absorb heat during the day and radiate it back out at night. During the summer, Manhattan is often 7 degrees warmer due to the heat island effect.

Air conditioning, in effect, creates its own ecosystem. To cool off without sending carbon emissions off the charts—a huge potential crises as more and more people across the globe move to urban areas—cities need to promote and fund more natural methods of cooling off.

City planners have already been promoting numerous strategies to blunt the effects of increasingly warm weather. Increasing green space and adding shade offer residents a respite, while promoting green roofs, reflective coverings, and the addition of photovoltaic panels can both reflect and absorb heat, while increasing green energy production.

Even small changes can truly add up: a study conducted by Concordia University suggests that by increasing the amount of white rooftops by just 1 percent across the globe, the adding reflectivity would provide enough of a cooling effect to keep more than 100 billion tons of carbon dioxide out of the atmosphere over the next century. A recent International Energy Agency report noted that investing in solar-powered air conditioning can cut cooling costs by up to 25%.

Oftentimes, the most effective solutions are the most simple. Many planners and park officials in cities such as Denver, Chicago, and Philadelphia have made a concerted push to restore and replant trees in an effort to provide a natural canopy and help cool urban centers. It’s an effort taking place across the country, even in the perhaps unlikely desert metropolis of Phoenix. There, Forestry Supervisor Richard Adkins is promoting an ambitious plan to cover a quarter of the city with tree canopy, a huge undertaking in an area considered a poster child for the detriments of sprawl (and one that, according to a report from Climate Central, is one of the fastest-warming in the country).

"Phoenix is going to continue to grow," says Adkins. "In order to develop sustainably, we need green infrastructure in place. It can’t just be gray. The health, environmental, and educational benefits have been proven by multiple studies."

Adkins’ Tree and Shade Master Plan, may read like a fantasy to those with a stereotypical view of Phoenix: by 2030, the city will double the amount of tree canopy. But in many ways, the future Askins envisions is merely returning the region to its past. Once criss-crossed with irrigation channels, due to its early agricultural industry, Phoenix was known as the "city of gardens." Before asphalt and development amplified the heat island effect, rows of trees provided a natural means of lowering the temperature.

After a decade in Phoenix, Adkins’s has achieved substantial buy-in from the mayor and local government, mostly due to the numerous benefits of proper urban forestry.  From absorbing water runoff (a big issue during flash floods in the dry desert) to cooling the ground and making it more comfortable to be outside, reducing trips in cars, planting can play a huge role. 

This back-to-nature approach is the lynchpin of many major climate plans in cities across the globe. In Berlin, planners want to create "sponge cities" and encourage the construction of more green roofs and urban wetlands, anything to add more plants and restore natural water flow, which prevents rapid evaporation and mediates heat gain.

Other design professionals been incorporating and experimenting with ways to alter building designs to promote natural cooling and energy efficiency. Most striking, however, are the increasing ways architects are incorporating natural features into new building designs. One of the most striking examples of this is Singapore’s OASIA, a recently completed 30-story structure that features exterior walls as trellises. The building, which will eventually be wrapped in green when plants finish growing along the exterior, will benefit from natural cooling and cross-ventilation, with a blooming exoskeleton significantly cutting cooling costs compared to other towers in the tropical city-state.

"Examining the central business districts of so many cities is like looking at the moon from the Earth; one is filled with life, the other is just this collection of dead stone," the designer of the building says. "With Oasia, we’ve seen so many birds and insects flying around the building. People respond so well to seeing a hummingbird flying right outside their office window."

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