Satellites zoom in on cities’ hottest neighborhoods to help combat the urban heat island effect


Article by Daniel P. Johnson: “Spend time in a city in summer and you can feel the urban heat rising from the pavement and radiating from buildings. Cities are generally hotter than surrounding rural areas, but even within cities, some residential neighborhoods get dangerously warmer than others just a few miles away.

Within these “micro-urban heat islands,” communities can experience heat wave conditions well before officials declare a heat emergency.

I use Earth-observing satellites and population data to map these hot spots, often on projects with NASA. Satellites like the Landsat program have become crucial for pinpointing urban risks so cities can prepare for and respond to extreme heat, a top weather-related killer.

Among the many things we’ve been able to track with increasingly detailed satellite data is that the hottest neighborhoods are typically low-income and often have predominantly Black or Hispanic residents….

With rising global temperatures increasing the likelihood of dangerous heat waves, cities need to know which neighborhoods are at high risk. Excessive heat can lead to dehydration, heat exhaustion, heat stroke and even death with prolonged exposure, and the most at-risk residents often lack financial resources to adapt.

Map of Chicago showing how heat deaths clustered in the urban core during the 1995 heat wave.
The July 1995 Chicago heat wave was blamed for over 739 deaths in a five-day period. Most victims were poor and elderly people who lacked air conditioning or feared opening windows because of crime. This figure shows the location of heat-related deaths clustered in areas of higher surface urban heat intensity.

Satellite instruments can identify communities vulnerable to extreme heat because they can measure and map the surface urban heat island in high detail.

For example, industrial and commercial zones are frequently among the hottest areas in cities. They typically have fewer trees to cool the air and more pavement and buildings to retain and radiate heat…(More)”