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Analysis: Climate Crisis Made Heat Wave Hitting Western US 5 Times More Likely

Some areas will experience record high temperatures, including Las Vegas, which could exceed 117 degrees this weekend.

In an aerial view, a Caltrans changeable message sign on Highway 101 displays a warning about extreme heat on July 2, 2024, in Corte Madera, California.

Millions of Americans in the western United States are set to feel the effects of a massive heat wave this weekend that could last for up to two weeks, with temperatures set to break record highs in several areas.

The heat that will be experienced is undoubtedly a result of human-made climate change, an analysis of the high temperatures has found.

According to ABC News, around 170 million Americans will be affected by excessive heat throughout the country, including in parts of California, Nevada, Arizona, Washington and Oregon. Portions of the South and the Mid-Atlantic states are also set to see “dangerous” levels of heat.

The National Weather Service (NWS) is warning that the heat could pose physical dangers to people who are outside for too long, stating on its account on X that those in affected areas should “limit time outdoors” and monitor themselves “for signs of heat related illnesses.” The NWS added that the Western Heat Wave would continue “through much of next week.”

The west had been experiencing heat for several days well before the July 4 holiday, but forecasters are saying that the remaining days of the heat wave will likely be even worse. Excessive heat warnings currently cover a majority of California, and temperatures in Las Vegas are predicted to come very close to its all-time record high of 117 degrees Fahrenheit.

The long-lasting heat that has persisted, coupled with the heat wave that’s about to take off, is also worsening wildfire conditions throughout the west, and will likely exacerbate existing wildfires. One such wildfire, the Thompson Fire in Northern California, has already consumed more than 3,000 acres. Around 26,000 residents of Oroville, California, had to be evacuated because of the fire.

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Excessive and record-breaking heat waves and wildfires are tied to the effects of the climate crisis, and this current heat wave is no different, according to an analysis from Climate Central.

That organization produces a “Climate Shift Index,” a daily measure of how likely it is that a given area’s temperature was affected by the climate crisis. A score of 0 on the index indicates that climate change had no effect on temperatures, while a score of five means there was an exceptional effect.

As of July 5, most of California was within that five rating, meaning that human-caused climate change made the conditions within those areas at least five times more likely, and potentially more so.

Climate scientists have warned that people must be extra cautious during this holiday weekend, noting that heat warnings are not to be downplayed.

“Heat is an underrated killer,” Daniel Swain, a climate scientist at the University of California, Los Angeles, told The Associated Press about the current heat wave. “It’s one we’ve long underestimated. And I think we continue to do so at our peril.”

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