Blog Post: Parks are a natural defense mechanism against the normalizing heat waves
BY JORDAN MULLANEY
The scorching hot temperatures experienced in June 2021 shattered records in cities and states across North America. Wildfires sparked, pavement buckling, power lines melting, and hundreds of deaths attributed to the historic heatwave in the Pacific Northwest and Canada.
While the District was left unscathed with near-average temperatures in June, Washingtonians should brace for the hottest temperatures yet to come. As many Americans are awakened through first-hand experiences of the catastrophic effects of the climate emergency, we’re reminded of the central role parks and green spaces play in keeping cities cool amidst the heat waves.
Urban areas experience what’s known as the “heat island effect” -- when dense concentrations of pavement, buildings, and other built surfaces absorb and radiate heat, causing temperatures to climb as much as 22°F warmer than neighboring rural areas. Unsurprisingly, summer heatwaves intensify this effect and create life-threatening conditions for at-risk or senior populations. Not to mention, you can expect increased reliance on cooling systems that overload power grids and increase CO2 emissions.
Parks as a Solution
Trees and vegetation are natural guardians against urban heat islands. Whether it’s a pocket park, street tree, or soccer field, green spaces stay cooler than the built environment. Countering the effect of the artificial temperatures in cities, green spaces cool the air through both shading and evapotranspiration -- the movement of water from the plant to vapor in the atmosphere.
Increased coverage of green spaces not only makes the District more livable, but also more survivable. As temperatures continue to break records, healthy trees and vegetation in open spaces prove themselves as invaluable defense mechanisms against an intensifying climate emergency.
Is the District Prepared?
Washington, DC set a goal for 40% healthy tree canopy coverage by 2032. Yet, a tug-of-war ensues, with the fear of stunting the District’s growth and development in place of a growing tree population, which funnels money into the economy, alongside concrete and increased energy consumption and costs.
According to the Trust for Public Land’s 2021 ParkScore, low-income communities actually have access to 50% more park space than the city median, and 9% more than those in high-income areas.
Despite the findings, the heat island effect is more severe in low-income neighborhoods, which cannot be overlooked. Discriminatory housing practices through redlining policies shaped these disparities as they left communities astray, without investment into cooling infrastructures like tree canopies of higher-income areas.
D.C.’s historically underserved African-American communities face extreme heat, where residents are more at risk of heat-related illnesses. Within the boundaries of the District itself, studies have shown temperatures differences ranging from 16°F between the hottest and coolest neighborhoods. D.C. Policy Center identified the neighborhoods at highest risk of heatstroke or heat-related illnesses include those of Buzzard Point, Edgewood, and Washington Highlands. The interactive map clearly highlights the disparities of the District’s east and west quadrants, with a particular need in Wards 7 and 8.
Extreme heat can longer be written off as a minor annoyance. The history and data supporting D.C.’s disparities facing extreme heat conditions must be used as a roadmap in preparing for the oppressing environments to come in this climate emergency.
Parks, green spaces, tree canopies, and vegetation, are the natural solutions to urban heat islands, and their ancillary benefits of cleaning surrounding air, improving water quality, and trapping pollutants (not to mention their mental health benefits, too), make them a no-brainer for the types of investment the District should be prioritizing.
With rising temperatures to come, transforming asphalt into cool, green city parks matters more than ever -- and might even be the matter of life and death.
Jordan Mullaney, Communications & Social Media Liasion, Green Spaces for DC