How climate change drives hotter, more frequent heat waves. Everything you need to know about the science linking global warming to extreme heat. Heat waves around the world are happening more frequently and reaching higher temperatures because of climate change. We know this thanks to the rapidly growing field of attribution science, which allows scientists to examine the link between rising levels of atmospheric carbon dioxide and extreme weather events. When a heat wave strikes — or another disaster, for that matter, be it a hurricane, drought, or very heavy rain — attribution scientists can determine the role that climate change played in its intensification. With extreme heat in particular, the answer is often tens or even hundreds of times more likely, thanks to a complicated mix of factors like abnormally dry soils and hotter-than-usual air. In fact, scientists are now comfortable assuming that all heat waves are being made more severe or likely because of climate change. At any given time, extreme heat is now affecting about one-tenth of the Earth’s land area, and scientists have observed an eightfold increase in record-breaking hot months over the past decade, compared to what would be expected in a world without climate change.  A cooling weather pattern called La Niña has suppressed global temperatures since 2020, but scientists announced this spring that a new, hotter pattern — El Niño — is emerging to replace it. Although experts say its full effects won’t be felt until next summer, it may already be contributing to some of this summer’s heat extremes.  Heat, one of the best-understood extreme weather events tied to climate change, doesn’t tend to draw the same attention as other disasters like hurricanes and wildfires. But that may be starting to change. In the U.S., scorching temperatures cause more deaths than any other weather-related disaster, claiming nearly170 lives every year. And as climate change drives global temperatures even higher, heat waves will only become more lethal, disrupting the lives of billions of people across the planet.   Most heat waves do share a common origin story, though. Broadly speaking, they form when ahigh-pressure air system parks itself over land, forcing air to sink to the ground. This air heats up as it compresses and becomes trapped, unable to dissipate into the upper atmosphere. Such a system also makes cloud formation less likely. (Cold air forces water out relatively quickly compared to hot air, and this water becomes clouds.) This allows more sunlight to reach the ground and exacerbate warming. There are a few additional “ingredients” that can converge to create a heat wave. Drier conditions, for example, mean more of the sun’s energy can go toward heating the air rather than evaporating water from plants and the soil. The time of year can also play a role: At latitudes farther from the equator, the Earth’s tilt can lead to summer days with 15 hours or more of sunlight — a long time for heat to build up. All these factors in combination are “a recipe for a lot of sunlight and warming, stagnant air,” Horton said.  Huge atmospheric wind patterns called jet streams also play a role in forming heat waves........read on.         https://grist.org/extreme-heat/how-climate-change-drives-hotter-more-frequent-heat-waves/?utm_medium=email&utm_source=newsletter&utm_campaign=weekly                       https://open.substack.com/pub/billmckibben/p/i-told-you-so?r=mwxsy&utm_campaign=post&utm_medium=email