Early Southwest heat is latest in parade of weather extremes as Earth warms

WASHINGTON (AP) — The dangerous heat wave that shattered March records across the U.S. Southwest is more than just an extreme weather incident. This is a final, next-level weather disaster that is occurring with increasing frequency as the Earth warms.

Experts said unprecedented and deadly extreme weather, which sometimes hits at abnormal times and in unusual places, is putting more people at risk. For example, the Southwest is accustomed to dealing with deadly heat, but not months ahead of schedule, including a temperature of 110 degrees Fahrenheit (43.3 Celsius) in the Arizona desert on Thursday that exceeded the highest March temperature recorded in the United States.

On Thursday, locations in Arizona and southern California recorded preliminary temperatures of 109 F (about 43 C), which would be the hottest March day on record in the United States.

“This is what climate change looks like in real time: extremes beyond the limits we once thought possible,” said Andrew Weaver, a climate scientist at the University of Victoria. “What were once unprecedented events are now recurring features of a warming world. »

March’s heat would have been virtually impossible without human-caused climate change, according to a report released Friday by World Weather Attribution, an international group of scientists who study the causes of extreme weather events.

More than a dozen scientists, meteorologists and disaster experts interviewed by The Associated Press placed the March heat wave in a kind of ultra-extreme classification with events such as the 2021 Pacific Northwest heat wave, the 2022 Pakistan floods and the deadly hurricanes Helene, Harvey and Sandy.

The area of ​​the United States affected by extreme weather over the past five years has doubled from 20 years ago, according to the National Oceanic and Atmospheric Administration’s Climate Extremes Index, which includes various types of extreme weather, such as heat and cold waves, downpours and drought.

The United States is now breaking 77% more heat records than in the 1970s and 19% more than in the 2010s, according to an AP analysis of NOAA records. In the United States, the number and average cost of billion-dollar weather disasters, adjusted for inflation, over the past two years are twice as high as a decade ago and nearly four times as high as thirty years ago, according to records maintained by NOAA and Climate Central, a nonprofit group of scientists and communicators who research and report on climate change.

Trying to follow extremes and failing

“It’s really hard to keep track of how extreme our extremes are getting,” said Bernadette Woods Placky, chief meteorologist at Climate Central. “It’s changing our risk, it’s changing our relationship with weather, it’s putting more people in risky situations and sometimes we’re not used to it. So yes, we’re pushing the extremes to new levels in all types of weather conditions.”

For government officials facing a disaster, this presents a huge problem.

Craig Fugate, who led the Federal Emergency Management Agency until 2017, said he saw an increase in extremes.

“We were increasingly operating outside of the historical playbook. Flood maps, surge models, heat records – events kept appearing outside of the envelope around which we built systems. That’s exactly what we saw,” Fugate said by email.

He added: “We’ve built communities on about 100 years of past weather and assumed that was a good guide to the future. That assumption is starting to break down. And the clearest signal is not the scientific debate. It’s the insurers pulling out.”

“Virtually impossible” without climate change

Climate scientists at World Weather Attribution conducted a flash analysis – which has not yet been peer-reviewed – to determine whether climate change was a factor in this Southwest heat wave. They compared the temperatures expected this week to those seen in the region in March since 1900 and to computer models of a world facing climate change. They found that “events as hot as March 2026 would have been virtually impossible without human-induced climate change.”

This warming, due to the burning of coal, oil and natural gas, added between 4.7 and 7.2 degrees F (2.6 to 4 degrees C) to felt temperatures, according to the report.

“What we can say with certainty is that human-caused warming has increased the temperatures that we see because of this thermal dome, and that’s going to take those temperatures from what would have been very uncomfortable to potentially dangerous,” said Clair Barnes, co-author of the report and an awarding scientist at Imperial College London.

Examples abound of extreme heat and weather conditions

The Southwest heat wave falls firmly into the “giant event” category, with temperatures up to 30 degrees Fahrenheit (16.7 degrees Celsius) above normal, said Chris Field, a climate scientist at Stanford University.

He listed five others in the past six years: a 2020 Siberia heat wave, the 2021 Pacific Northwest heat wave that made British Columbia hotter than Death Valley, summer 2022 in North America, China and Europe, a 2023 western Mediterranean heat wave and a 2023 South Asia heat wave with high humidity.

And that doesn’t include the 2022 East Antarctic heatwave, when temperatures were 81 degrees (45 degrees Celsius) warmer than normal. It’s the largest anomaly on record, said weather historian Chris Burt, author of the book “Extreme Weather.”

Worsening wild weather influenced by climate change is not limited to very hot days, but also includes deadly hurricanes, droughts and downpours, scientists told the AP.

Devastating floods hit West Africa in 2022 and again in 2024. Iran is in the midst of a six-year drought. And the deadly Typhoon Haiyan that hit the Philippines in 2013 shocked the world.

Superstorm Sandy, which flooded New York City and its neighbors in 2012, brought tropical storm-force winds that covered an area nearly one-fifth the size of the contiguous United States. It spawned seas 12 feet high across 1.4 million square miles, about half the size of the United States, with energy equivalent to five Hiroshima-sized atomic bombs, said Yale Climate Connections meteorologist Jeff Masters.

And don’t forget wildfires that are made worse by heat and drought, so recent extremes are expected to include the Palisades and Eaton wildfires in 2025, which were the costliest weather disaster in the U.S. last year, said Adam Smith, a Climate Central meteorologist and economist.

“This is due to climate change, the fact that we are seeing more extreme, more intense events and so many records are being broken,” said Friederike Otto, a climatologist at Imperial College London who coordinates global weather allocation.

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