WEATHER

Even October is hot. Here's how many extra days of heat the U.S. gets

Brandon Loomis
The Republic | azcentral.com
Lili Lopez cools with drinks of water before Game 1 of the World Series in Los Angeles on Oct. 24, 2017. As baseball fans headed to Dodger Stadium for the first game of the World Series, temperatures in downtown Los Angeles hit a record-breaking 103 degrees by early afternoon.

The World Series opened Tuesday on a sunny Los Angeles day with triple-digit heat. But those temperatures are hardly unexpected in our warming world.

Millions of Americans experience more than an extra week of summer heat that would have seemed extreme a generation ago. Sometimes the summer heat outlasts summer.

As Los Angeles sweltered at a record 104 degrees on Tuesday and Phoenix climbed to a record 99, environmentalists and public-health specialists focused attention on the rising heat they consider a growing crisis.

"The summers of the past no longer speak to the summers of the present," said Kim Knowlton, a senior scientist for the Natural Resources Defense Council. The group released a map and report Tuesday detailing the rise of extreme heat by U.S. county.

More than 210 million Americans and most Arizonans experience at least nine days extra of extreme heat each summer, according to an NRDC analysis. In Arizona, only Pinal and Santa Cruz counties saw smaller rises of super-heated days.

The group's scientists charted the hottest 10 percent of days of the three-month summers in every county from 1961 to 1990 and calculated how many more days broke into that temperature range yearly in the 2007-2016 decade.

Some counties in Arizona — the state's entire western flank, plus Pima and Greenlee counties — experienced 15 or more extra days of extreme heat.

MORE FROM OUR SPECIAL REPORT: 
PART 1: Phoenix's heat is rising — and so is the danger
PART 2: How heat discriminates
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Extreme heat's link to global warming is established, making more weeks like this record-breaker ever likelier, University of California, Los Angeles, climatologist Daniel Swain said.

While a hot World Series first pitch "might not be a formal climatological indicator," he said, "it's certainly representative of broader regional and global trends."

Public-health threat

A client takes advantage of the heat-relief hours in the chapel of the Society of St. Vincent de Paul in downtown Phoenix in June.

Heat is a growing public-health threat, especially for the poor, the homeless, the sick or aged, and the very young. 

Parents must be more mindful about protecting children from heat than they may recall from their own childhoods, Virginia Commonwealth University pediatrician Samantha Ahdoot said during a news conference about the NRDC report.

She recalled days of treating a teen football player who had collapsed in August heat, and said studies show heat-related athlete deaths and emergency room visits have doubled or worse in recent decades.

As the Arizona Republic reported this month, hundreds of Maricopa County residents have died of heat-related causes in recent years. It happens as springtime highs begin warming, and the rate spikes on days when Phoenix hits 110 degrees or doesn't drop below 90.

The heat also afflicts neighborhoods unequally, based on factors such as shade and air-conditioning.

Programs can save lives

Los Angeles sweated into its Fall Classic opener on Tuesday, but it has begun actions to reduce heat stress on its vulnerable residents. The city has an ordinance requiring all new roofs meet reflective standards to absorb less solar energy.

More action is needed nationwide, said Linda Rudolph, director of the Public Health Institute's Center for Climate Change & Health.

Cities can invest in trees, cooler pavements, greener spaces and shaded playgrounds, she said. They can coordinate longer hours in public spaces like malls and libraries during heat emergencies. They can educate people about cooling centers and federal assistance with paying power bills for air-conditioning.

Rudolph argued against a proposed federal-budget plan eliminating that support for low-income people.

"We can literally save lives," she said.

Knowlton argued that the county heat data suggest the lack of wisdom in the Trump administration's rejections of carbon-cutting movements such as the Paris Agreement or the Clean Power Plan.

"Its a bad idea for the United States to pull back from climate action," she said.

Skeptics reject the notion that carbon is responsible for the warm-up of places like Phoenix. William Boyes, founding director of Arizona State University's Center for the Study of Economic Liberty, said the heat-absorbing buildup of urban areas is a likelier culprit.

"The carbon effects are very overrated," he said.

'What we should expect'

A cyclist lays down in the shade on a bench in Griffith Park in Los Angeles on Oct. 23, 2017.

California's warming climate may or may not be provably responsible for Tuesday's scorcher, but it does make such a toasty World Series likelier.

"It's exactly what we should expect," Stanford University climate researcher Noah Diffenbaugh said.

California's baseline is warmer than it was last century, and that means it takes fewer weather variables to boost a given heat wave to new heights, he said. That's why the U.S. now logs about twice as many new records for heat as it does for cold in a year.

As a scientist reviewing global statistics, he wasn't surprised by Tuesday's weather. As a lifelong Californian walking across his Palo Alto campus, he was.

"It's late October, and it's hot," he said.

Environmental coverage on azcentral.com and in the Republic is supported by a grant from the Nina Mason Pulliam Charitable Trust. Follow the azcentral and Arizona Republic environmental reporting team at OurGrandAZ on Facebook, Twitter and Instagram.

 

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