Vangie Jacobo wipes her face with a wet cloth while working outside in 106 degree heat in Phoenix, Arizona on July 23, 2022. REUTERS/Rebecca Noble
July 24 (Reuters) – Virtually all of the contiguous United States experienced above-normal temperatures in the past week, with more dangerously hot weather forecast. read more
The US heatwave followed record heat that killed hundreds if not thousands of people and sparked wildfires in Europe. read more
Following is an explanation of what causes heat waves, according to scientists.
WHAT IS A HEAT WAVE?
A heat wave does not have a single scientific definition. Depending on the climate of a region, it can be determined by a certain number of days above a specific temperature or percentile of the norm.
ARCTIC WARMING AND JET STREAM MIGRATION
The Arctic is warming three to four times faster than the globe as a whole, meaning that there is less and less difference between northern temperatures and those closer to the equator. See the article : Policy Report: People asked for time and now they’re getting time because what they really wanted was time.
This creates oscillations in the North Atlantic jet stream, which then leads to extreme weather events such as heat waves and floods, according to Jennifer Francis, senior scientist at the Woodwell Climate Research Center.
HEAT DOMES
Warm oceans contribute to the heat dome, which traps heat over large geographic areas. This weekend, the heat dome will stretch from the southern beaches of the Oklahoma/Arkansas region to the eastern seaboard, according to the U. To see also : The federal office focused on the impacts of the climate crisis on health has no permanent staff or funding.S. Weather Prediction Center.
Scientists have found that the main cause of the heat dome is a strong change in ocean temperatures from west to east in the tropical Pacific Ocean during the previous winter.
“As prevailing winds move the warm air eastward, the northward shifts of the jet stream trap the air and move it landward, where it sinks, resulting in heat waves,” the US National Oceanic and Atmospheric Administration says on its website.
EL NIÑO AND LA NIÑA
Every few years, the climate patterns known as El Niño and, less frequently, La Niña occur. To see also : Women scientists aren’t getting authorship they should, new study suggests. El Niño brings warm water from the equatorial Pacific Ocean to the west coast of North America, and La Niña brings colder water.
Currently, La Niña is in effect. Because summer temperatures tend to be lower during La Niña, climate scientists are concerned about what a serious heat wave will look like during the next El Niño, when even hotter summer weather is expected.
HUMAN-INFLUENCED CLIMATE CHANGE
Climate change caused by the burning of fossil fuels is a global phenomenon that is certainly playing a role in what the United States is experiencing, scientists say.
“Climate change is making extreme and unprecedented heat events more intense and more frequent, pretty much universally across the globe,” said Daniel Swain, a climate scientist at UCLA.
“Heat waves are probably the most underestimated type of potential disaster because they routinely kill a lot of people. And we just don’t hear about it because it doesn’t kill them, to put it bluntly, in dramatic enough ways. There are no bodies on the street.”
Francis, of the Woodwell Center, said with climate change the world is changing wind patterns and weather systems “in ways that make these heat waves, as we see now, more intense, more persistent, and cover areas that are just not used to having heat waves.” “
Alex Ruane, a researcher at NASA’s Goddard Institute for Space Studies, said as the world warms, “it takes less of a natural anomaly to push us into the extreme heat categories. As we get closer to those thresholds, it’s more likely that you “will get more than one heat wave at the same time.” We see that in the United States.”
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Report by Daniel Trotta; Editing by Donna Bryson and Rosalba O’Brien
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