By Meredith Jennings, PhD, Research Associate, Community and Climate Resilience; Rachel Correll, Science Policy Fellow, NASEM Gulf Research Program; and McKenzie Roberts, Research Assistant, Energy and Environment
Houstonians are used to the heat, enduring summer after summer of warm, humid temperatures until cooler fall weather provides a welcome relief. However, summers are getting both warmer and longer. In fact, 2020 tied with 2016 as the hottest year on record.
Last summer, HARC joined the Houston Harris Heat Action Team along with the City of Houston, Harris County Public Health, and the Nature Conservancy of Texas, to help find Houston and Harris County’s warmest places through a one day community science mapping campaign managed by CAPA Strategies and NOAA.
The project sought to address many questions, including:
How will longer, warmer summers change life in the Houston region? How will we adapt? Not every location heats up the same. Are the places that we live, learn, work, and play currently able to keep us healthy and cool? Which areas need more help getting cool? What can we learn from areas that are cooler?
At 6 AM, 3PM, and 7PM on August 7th, 2020, teams of volunteer community scientists simultaneously drove one-hour routes across 32 Houston and Harris County neighborhoods with temperature and humidity sensors attached to their cars.
The H3AT campaign was larger than any other campaign conducted by NOAA/CAPA by over 120 square miles, made possible by the efforts of 84 community scientists from Houston and Harris County.
The campaign resulted in a series of maps depicting temperature and heat index throughout the day, shown below as traverse points (original measurements made by the community volunteers) and as results modeled to a larger area (based on the measured values and satellite data of land surfaces).
When we compare the temperature results to the land cover imagery, we can see that areas with more trees and green spaces are often cooler than areas developed with streets and buildings. This is something you’d expect to see since trees and vegetation provide shade and reduce the temperature of the air through a process called evapotranspiration. However, trees can also block breezes and contribute to the relative humidity, which can make the heat index, or “feels like” temperature, feel warmer. These are examples of potential impacts we plan to examine more closely.
Heat is disproportionately distributed across the Houston area with some areas, such as southwest of the Galleria, measuring ground temperatures as high as 103 degrees. Temperatures tend to be higher in more densely populated areas as well as more industrial areas. Several areas across the Houston area did not cool below 80 degrees. Nighttime cooling is important to help human and animal bodies rest and reset. There is an increase in heat related health issues when there is not enough cooling.
It is important to remember that heat affects everyone differently and not everyone has the same resources (such as air conditioning) to adapt. The elderly, the young, those with preexisting conditions (especially heart-related), people working outside, pets, and people with mental illnesses are at most risk. We can help combat the rising heat by planting more trees, reducing the carbon footprints of buildings and cars, planting rooftop gardens or painting roofs white, using more reflective and permeable paving, and by checking on our neighbors when temperatures rise.