From Inside Climate News, a report on how summers are expected to be hotter soon, and what we can do about it.
Temperatures can vary across big cities like New York and Houston, depending on the landscape and the amount of green space and trees in a given neighborhood. Local scientists and community organizations have worked to understand the urban heat island effect over the past few decades. But the average city resident doesn’t always know that their neighborhood may feel hotter than the temperature from weather forecasts.
Around 150 Houston residents attached temperature sensors to the windows of their cars and drove around the city in 2024 to document the urban heat island effect in real time. This was the second study of its kind for the Houston Advanced Research Center; the first happened in 2020.
As expected, the results showed that areas with denser development and less tree cover were hotter. For many volunteers, it offered a snapshot of a problem that they can feel the effects of, but may not always be able to prove. It was not just about the science, said Meredith Jennings, the director of local government and community initiatives at the Houston Advanced Research Center, who worked on both experiments.
“For people to participate in this campaign and talk about it on the news and see how heat impacts people differently,” she said. “That can inform how people take action.”
From 2016 to 2024, the National Oceanic and Atmospheric Administration, in partnership with other federal agencies, funded the mapping of the urban heat island effect in American cities, including Houston. The U.S. Department of Agriculture funded the second study through a program to increase tree canopy in underserved communities. With recent federal cutbacks on climate research, the future of mapping heat and cooling in cities may now rest more firmly on the shoulders of local leaders.
In many cities across the country, you are more likely to live in a hotter neighborhood if you are low income or a person of color.
Communities in neighborhoods with very little green space have also often suffered because of their proximity to industry, such as power plants—which release heat while operating—and highways. A recent study found that highway expansions can considerably worsen the heat island effect.
In hotter neighborhoods, air conditioners are often used more frequently. Research has linked buildings’ higher cooling energy demand to urban overheating—and that’s if the resident even owns an air conditioner and can afford to use it amid rising electricity costs.
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Climate change is making our summers warmer, and this summer seems poised to continue that trend.
City governments that want to cool down hot neighborhoods can take practical steps like adding green spaces and street trees as well as using roof and pavement materials designed to absorb less heat.
Although planting trees is a proven way to cool neighborhoods by providing shade and lowering air temperatures, maintaining street trees can be costly, especially when they are dying from drought.
In New York, the city’s forthcoming Urban Forest Plan will be designed to cover 30 percent of the city with tree canopy, in part to reduce heat in certain areas. I reported in December that the city received state funding to plant and care for trees in its ailing forests. But the underfunded Parks and Recreation Department may struggle to keep up.
Since 2020, Houston leadership has been tracking tree plantings across the city, in line with a city plan that sets out a framework to achieve carbon neutrality by 2050, and greater resilience to climate change. According to the plan, city residents are forecast to experience 74 days a year with a heat index—a measure that assesses how a mix of heat and humidity feels to the human body—of 105 or more by 2050. Currently, they experience an average of only 10.
“Climate projections and the historical trends—they’re all pointing toward summers becoming more and more unbearable and longer,” Jennings said. “So this really becomes a quality of life issue.”
See here for some background on the Houston heat mapping project, which was a very cool thing that some friends of mine got to participate in. I hope this is a continued effort, because we need to know all we can about what heat is doing to our city. Over two full months of a heat index over 105? I like summer, but not that much. Of course there’s only so much any local government can do about this. It’s depressing to think how far backwards we’ve gone in the last sixteen months, but we can’t give up hope. We’ve still got to do what we can to make things better, because we’re going to need it for ourselves.