This article is part of Earth Refuge’s Spotlight Series on Philadelphia
During the summer of 2021, cities across the United States (‘US’) have seen record breaking temperatures to an extent that scientists say would have been “virtually impossible” to reach without anthropogenic climate change. Cities are especially prone to such extreme heat because of particular characteristics which cause people within urban areas— particularly low-income residents — to bear an undue burden of the effects of climate change.
What is the Urban Heat Island Effect?
Heat islands are urban areas that experience higher temperatures than their surrounding areas for a variety of reasons. For one, cities contain more man-made structures, such as buildings, roads, and dark roofs, which absorb and re-emit the sun’s heat more than natural land does. Additionally, more vehicles, more air conditioning units, and more industrial facilities all contribute to the heat island effect felt in cities across the world.
The city of Philadelphia is a paradigmatic heat island. Since 1970, Philadelphia’s average summer temperature has increased by three degrees Fahrenheit (-16 °C), leading to more extreme heat events. In the past fourteen years alone, heat-related events have caused nearly 150 deaths in Philadelphia. The magnitude of such tragedy is only expected to grow larger. Just this past summer, Philadelphia declared a Heat Health Emergency, which only occurs from May through June when temperatures are expected to reach 101°F (38 °C) or higher for two consecutive days, or 98°F (37 °C ) or higher for three or more consecutive days. This designation puts services like the city’s heatline into effect and bars any residential utility shutoffs.
The Disproportionate Impacts
Philadelphia is a quintessential heat island not only because the city has become hotter overall, but also because within the city — as in so many others — low-income neighborhoods and communities of color face disproportionate impacts of the increasing temperatures.
