It’s Getting Hot in Here!

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As a kid going on family camping trips I still remember the exaggerated inhale of ‘fresh mountain air’ upon arriving at our destination, purging our lungs of that stale ‘city air’ and remarking on how crisp and clean it felt in comparison. During the past few weeks, as D.C. and cities across the country faced record temperatures, I was reminded again of that contrast, though this time not even having to leave the city.

Living in a relatively ‘green’ area of D.C. – in close distance to natural assets such as Rock Creek Park and along a thickly tree-lined street – I can’t help but notice the stark difference in temperature between my neighborhood and areas closer to downtown, just 3miles from my front door. The difference? Far less air-cooling ‘green’ and significantly more heat-retaining ‘grey’.

Scientists have long studied the increased temperatures of urban compared to rural areas, and have termed particular areas of cities “heat islands.” While mention of “the islands” may at first elicit notions of cool air and tropical breezes, urban heat islands could not be further from this refreshing image. As the built environment of many cities overtakes, paves over or significantly reduces natural assets, the resulting concrete, asphalt, and other dark surfaces are left exposed, soaking up and reflecting the sun’s rays during the day and continually releasing excess heat throughout the evening.

Heat islands result in higher A/C use (and thus whopping energy bills) of surrounding homes and businesses, can cause increased stormwater runoff, have been shown to contribute to heat-related illnesses, and may even negatively impact surrounding businesses as people are less likely to spend time in these areas.

Scientific evidence demonstrating the negative byproducts of “heat islands,” is plentiful however even without quantitative data it should come as no surprise that these types of land use patterns have little to be desired. After all, when given the choice between spending an afternoon strolling along a tree-lined street, in a park or along a landscaped walking path and spending that same afternoon surrounded by concrete in the blazing sun – not too many people, would likely line up for the second option. The first scenario includes what is commonly termed “green infrastructure” and includes elements such as urban forestry, greenspace, gardens, landscaped areas, and vegetation. All of these elements (and more) are considered effective strategies to mitigate against “heat island” impacts and create more welcoming – and comfortable – communities. And while the aesthetic benefits are easily understood – too often, especially during times of economic strain, these assets are seen as simply that – beautification or “nice to have” amenities, but not priority investments and certainly not often seen as “infrastructure” in the traditional sense.

Studies examining the benefits of urban forestry alone have demonstrated several direct and indirect benefits. Trees collect stormwater while shading and reducing energy use of buildings; retain moisture, thus cooling the air; and provide welcoming environments shown to benefit the local economy and even reduce crime.

And in what I think may be one of the coolest (pun intended) outcomes of green infrastructure – it actually makes sustainability and its various benefits immediately visible! While changing lightbulbs, creating bike lanes, and installing PV panels all significantly contribute to city sustainability and quality of life, few things get people’s attention like the presence of greenspace, urban forestry, gardens, parks for their kids to play in and attractive landscaping.

Though “beautification” may be perceived as the primary benefit, I see it more as an attractive byproduct of an otherwise super-charged infrastructure project. And while green infrastructure is in no way a complete replacement for traditional ‘grey’ stormwater management systems, it can significantly reduce pressure on these aging systems while producing countless above-ground benefits (all at rate that sits a bit easier on the bottom line). As temperatures rise, energy bills surge, stormwater management becomes a growing challenge, and cities seek strategies to attract business and residents and create a sense of place, perhaps it’s time to take a closer look at what we consider ‘beautification’?

To learn more about Heat Islands check out EPA’s comprehensive “Heat Island Reduction” program and join the webinar this Wednesday August 8th, “Ways to Beat the Heat: Effective Approaches to Heat Island Reduction”. Check out SCI resources on Green Infrastructure including NLC’s action guide.