Urban heat islands: rising temperatures and inequity
This summer was especially hot— from sweltering heatwaves in Paris to tropical humidity in California. While human-driven climate change is the primary factor of this heat, there’s a widely less understood contributor that works with climate change: the urban heat island effect. This phenomenon occurs when an urban area (the city) experiences much warmer temperatures than rural, undeveloped areas surrounding it. Because the sun reaches the city and rural areas the same way, the difference in temperatures is determined by the environment’s ability to absorb and release heat.
Think of a brick that’s been heating up in an oven: when you take it out, it’ll remain warm for a few hours. In the bigger picture, infrastructure in major urban areas acts as this brick. A local example of this was Downtown Los Angeles on September 9th, 2026, which met the record temperature of 105°F set in 2024. Due to the limited amount of greenspace and tall buildings spaced closely together, heat is easily trapped, and essentially forms a warm bubble around the city.
Though everyone experiences the effects of the urban heat island in some way, not everyone is equally affected. Studies have shown that communities living below the poverty line or with people of color suffer larger impacts in contrast to wealthier, white counterparts. On average, higher-income neighborhoods have 15.2% more tree coverage than lower-income neighborhoods, which act as an essential heat-mitigating landscape feature. The patterns leading to these inequities link to historical processes like redlining and zoning, shaping racial and economic segregation that continue in the present day. As a result, these communities are all the more vulnerable to intense heat events, exacerbating existing health and economic inequalities.
So, how might we try to solve this problem? Mitigating environmental issues often require careful planning and policy making, but the first steps can be made from the comfort of your own home. For rising temperatures and urban heat islands, many may have the immediate reaction of turning to air conditioning that keeps us cool during hot summer days. However, this dismisses the root cause of heat islands and the amount of energy being used in the long run. Instead, we can consider the addition of more trees, vegetation, and green/cooling roofs, as it is the single most effective solution. According to a study back in 2012 by the Natural Resources Defense Council, the Emmett Center of Climate Change, and the Environment at UCLA School of Law, installing green roofs in southern California could save up to $211 million in energy costs, which is the equivalent of removing 91,000 cars from the road each year. Installing a few drought resistant plants or painting reflective roofs are the simple steps you can take to mitigate the heat island effect.
Ultimately, urban heat islands are both a physical and systemic issue that continues to persist alongside climate change and global warming. By working collectively and investing in green infrastructure, cities can dismantle these structural disparities and pave the way for a cooler future.
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