The science behind heat waves
Tales of environmental disasters – wildfires, hurricanes, droughts, heat waves, heat domes – have crowded the news over the past months. There are now, on average, six heat waves per year in the United States, and more than 2,400 temperature records were broken between June and July (“What”). Scientists estimate that, at any one time, extreme temperatures are impacting about 10% of the globe’s land area (Winters). In July, “Earth logged its seven hottest days ever” (Winters).
Many of these reports have focused upon the social impacts of these events. However, it is also important to understand how and why they came about – even for ordinary citizens, whose collective efforts are the world’s best hope for combatting the environmental crisis.
Heat waves tend to follow a relatively predictable pattern of atmospheric events (“The”). First, air must sink through the atmosphere to form a high-pressure region at ground level; this compression, in turn, warms the air. If a high-pressure region remains in one area for a long period of time, a heat wave will occur.
The term “heat dome” can also be seen frequently in today’s news, but it is not synonymous with the term “heat wave”. Heat domes are the high-pressure atmospheric “lids” that condense air and trap heat, resulting in a heat wave (US). They typically trap hot air from the oceans; thus, a large or abrupt change in ocean temperatures can trigger the formation of a heat dome (“Heat”). Air heated by the ocean surface will rise, flow with jet stream patterns towards the shore, and then sink, scorching the land over which it falls.
Nearly all climate scientists agree that climate change is altering the jet stream patterns, as well as the strength with which they flow (“How”). However, this is not the only link between broader environmental issues and isolated heat wave events. Deforestation and the expansion of infrastructure have resulted in “urban heat islands”, or large, densely populated regions of “heat-trapping concrete and asphalt” that can amplify the effects of a heat wave (“Laboratory”). Atmospheric carbon dioxide, which absorbs heat and radiates it back towards the ground, has increased in concentration due to high levels of fossil fuel consumption (Lindsey).
If ordinary citizens are to effectively advocate for environmental reforms, it is essential that they understand how and why environmental crises are taking place, just as it is essential that they empathize with the victims of those crises.
“How Humans Are Breaking the Jet Stream and Changing the Weather.” Www.pennfuture.org, www.pennfuture.org/Blog-Item-How-Humans-are-Breaking-the-Jet-Stream-and-Changing-the-Weather#:~:text=In%20other%20words%2C%20global%20warming. Accessed 24 Aug. 2023.
Laboratory, By Sally Younger, NASA’s Jet Propulsion. “NASA Maps Key Heat Wave Differences in Southern California.” Climate Change: Vital Signs of the Planet, climate.nasa.gov/news/3280/nasa-maps-key-heat-wave-differences-in-southern-california/#:~:text=Climate%20change%20is%20fueling%20longer. Accessed 24 Aug. 2023.
Lindsey, Rebecca. “Climate Change: Atmospheric Carbon Dioxide | NOAA Climate.gov.” Www.climate.gov, 23 June 2022, www.climate.gov/news-features/understanding-climate/climate-change-atmospheric-carbon-dioxide#:~:text=Without%20carbon%20dioxide%2C%20Earth%27s%20natural.
US Department of Commerce, National Oceanic and Atmospheric Administration. “What Is a Heat Dome?” Oceanservice.noaa.gov, oceanservice.noaa.gov/facts/heat-dome.html#:~:text=High%2Dpressure%20circulation%20in%20the. Accessed 18 Aug. 2023.
“The Science of Heat Waves Explained.” KQED, www.kqed.org/news/11880497/the-science-of-heatwaves-explained. Accessed 18 Aug. 2023.
Winters, Joseph. “How Climate Change Drives Hotter, More Frequent Heat Waves.” Grist, 11 July 2023, grist.org/extreme-heat/how-climate-change-drives-hotter-more-frequent-heat-waves/. Accessed 18 Aug. 2023.
“What to Know about Heat Domes—and How Long They Last.” Time, 27 July 2023, time.com/6299072/what-to-know-about-heat-domes-and-how-long-they-last/#:~:text=Vecchi%2C%20professor%20of%20Geosciences%20at. Accessed 18 Aug. 2023.
“Heat Waves and Heat Dome.” Drishti IAS, www.drishtiias.com/paper1/heat-waves-and-heat-dome. Accessed 18 Aug. 2023.