Urban Strategies for Combating Climate Change

Thursday, June 30th, 2016
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Cities around the world are turning to innovative strategies for combating the worsening heat island effect in the wake of worsening climate change.

The impact of global warming on regional climates around the world is becoming an increasingly incontrovertible fact, with 2016 already on track to be the hottest year on record.

Temperatures around the world have reached unprecedented heights in recent months, with India logging a record heat level of 51 degrees Celsius and Australia seeing its warmest ever autumn.

Gains in global temperature levels will have a particularly adverse effect upon cities, given the fact they’re slated to host the preponderance of the world’s human population and the exacerbation of hot weather in urban areas by heat island effects.

In order to address the challenges that warmer climates will bring to the world’s urban centres, cities around the globe are turning to innovative methods to help combat worsening temperatures levels in built-up areas.

One of the most convenient, low-tech expedients currently in use by a major world city is Manhattan’s plan to simply change the colour of its building surfaces in order to help reduce the urban heat island effect.

A chief cause of the urban heat island effect is the darker surface colouring of many of the built assets and infrastructure that comprise modern cities, which serves to absorb radiant heat throughout the day.

In New York City, the black asphalt installed on many building roofs can approach temperatures of as high as 87 degrees Celsius during the summer months.

In order to mitigate this phenomenon, the NYC CoolRoofs program is covering large swathes of this roofing asphalt with a light coating that will help keep temperatures low by reflecting away more sunlight.

The program has already covered 6 million square feet of asphalt surface in New York, with plans to increase this amount by a million square feet of roofing per year. According to some estimates, the initiative could reduce the air temperature of New York by as much as two degrees.

Chicago has deployed a similar initiative to address the exact same problem blighting its own built assets using a slightly more hi-tech solution.

The Green Alleys program was first launched by the Windy City last decade, and has thus far seen the repaving of 200 smaller streets with a permeable, lighter-hued concrete that better reflects to the radiant heat of the sun, while also permitting rainwater to penetrate through street surfaces and soak into the earth.

The lighter concrete is now the standard material used for the upgrade and repaving of alleys throughout the city, while the initiative has inspired similar programs in other major American cities such as Los Angeles and Seattle.

A more active approach to addressing the problem of torrid urban temperatures involves the manipulation and channelling of natural air flow to produce cooling winds on city streets.

Urban planners in the German city of Stuttgart have long made use of this method, employing ventilation corridors to corral natural wind flow and direct it towards settled areas.

The method was first deployed in the 1930s, with the creation of green ventilation paths that dispatch cool winds from higher altitudes down into the valleys where much of the city’s built-up areas are located.

The proven effectiveness of this method is such that urban planners in China hope to use the method to cool and cleanse the smoggy air of Beijing.

The desert community of Masdar City in the UAE is turning to even more elaborate measures to channel natural wind flow for the purpose of cooling its parched urban areas.

While the model urban development has been plagued by setback and delay since first breaking ground back in 2008, the city’s cooling measures are a proven success story. When temperatures in the adjacent desert environment hover at a stifling 35 degrees Celsius, the city itself remains at a balmy 20 degrees or so.

One of the primary means by which Masdar City achieves this remarkable cooling effect is a wind tower in the campus courtyard, consisting of giant air funnel measuring roughly 45 metres in height.

The tower gathers cool air flowing at its apogee and funnels in towards the ground, generating a steady, artificial breeze that makes a vital contribution to the cooling of Masdar’s air.

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