Boston's roofs, roads, parking lots boost temps by up to 14 degrees
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Boston's roofs, roads and parking lots drive up temperatures in some neighborhoods by up to 14 degrees compared with less-developed areas, a new analysis suggests.
Why it matters: The city's hottest neighborhoods experience heat emergencies sooner and for longer than their cooler counterparts.
- That leaves residents in those areas more susceptible to heat stroke, dizziness and other side effects.
Driving the news: Nearly two-thirds of the city has roofs, parking lots, roads and other surfaces that absorb solar energy and don't let water pass through, per a new analysis from the nonpartisan nonprofit Smart Surfaces Coalition.
- These "impervious surfaces" absorb up to 95% of solar energy, causing air temperatures in highly developed parts of the city to increase, per the report.
- The coalition recorded a ground surface temperature of 116 degrees in Roxbury, while a pocket on the west side of the city was just over 78 degrees, said Greg Kats, the coalition's CEO.
Context: The Smart Surfaces Coalition promotes the creation of climate-resilient infrastructure, including green roofs, tree cover and porous pavements.
- Mayor Michelle Wu and four other city mayors joined the Smart Surfaces Coalition in 2023 to explore climate resiliency measures.
- The report relies on a combination of satellite data and modeled data from the last five years, which may not reflect the recent climate resiliency measures Boston has taken.
By the numbers: Boston has an estimated 106,000 roofs, nearly 3,000 lane-miles of road, and 570 acres of parking lots.
- They not only drive up air temperatures, but also generate an estimated 28 billion gallons of stormwater runoff, causing flooding and polluting area waterways.
- The coalition's map measuring surface temperature found at one point the ground in Roxbury reached 116 degrees, while a pocket on the west side of the city was just over 78 degrees, said Greg Kats, the coalition's CEO.
Zoom in: The climate resiliency measures the Wu administration has already started include adding green roofs on bus shelters and launching partnerships to support tree planting on private property in urban heat islands.
- Wu's office said the city has also added trees in neighborhoods with historically lower tree canopy.
- The analysis suggests that expanding urban tree cover by 4% and converting 1%-2% of city surfaces to porous pavements could manage 6 billion gallons of stormwater while improving water and air quality.
- It also says that adding "smart surfaces" can reduce peak summer air temperatures by between 5.3 and 7.3 degrees in typically hotter neighborhoods.
Yes, but: The report doesn't say how much these measures are costing taxpayers.
- Instead, the report claims "smart surfaces" could "provide local citizens with $554 million in public health benefits, $91 million in energy savings and $252 million in infrastructure savings" over the next 35 years.
What they're saying: Kats says Boston can either invest in efforts to cool surface and air temperatures, or leave it up to residents to install air conditioning units, which means higher electricity bills and more hot air getting dumped outside.
- "Boston really faces a choice between public cooling ... or private air conditioning, which makes everybody miserable."