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Record-Breaking Southwest Summers Will Likely Get Worse, Scientist Says

United States Postal Service letter carrier Brian Johnson, 55, takes a break from his 400 house mail route to hydrate with some water Monday, July 1, 2013 in Glendale, Ariz. CREDIT: AP PHOTO/RALPH FRESO
United States Postal Service letter carrier Brian Johnson, 55, takes a break from his 400 house mail route to hydrate with some water Monday, July 1, 2013 in Glendale, Ariz. CREDIT: AP PHOTO/RALPH FRESO

For Enrique Castañeda, the weather in Phoenix, Arizona, in the past four days can only be described with two words: “mad hot.”

“When I go run it feels like I have a blow dryer in my face,” the 25-year-old told ThinkProgress. “You don’t see many people outside.” Castañeda, who considers himself so much of a “desert cockroach” that he enjoys hot weather and sunsets that are “dark red like the sky is on fire,” even played some basketball on Saturday afternoon, despite thermometers registering an unusual 111 degrees.

His enthusiasm was short-lived. “I only lasted 20 minutes before I started feeling the heat affecting me,” he said.

The southwest deserts of the United States are naturally hot this time of year, with temperatures oscillating around the low 100s. Yet this year the late spring heat climbed way past the normal averages in Phoenix and multiple other cities, prompting officials to issue an excessive heat warning for the deserts that will end Wednesday.

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Experts reached said last weekend’s weather was unusually hot, but a study released this month found that summers across the globe will almost certainly break more records more often in the coming decades as global warming continues. Evidence of this can be seen already.

On Sunday, for instance, Phoenix reached 118 degrees, marking the 10th time this has happened since record keeping started in 1895. “We’ve only had it hotter [than 118 degrees] four times in Phoenix,” Andrew Deemer, a Weather service meteorologist, told ThinkProgress. “So when you look at it in that context it’s pretty unprecedented.” In Yuma, a county that borders California, temperatures reached 120 degrees, making it the fourth-hottest day on record there. “The message to really drill home is that this type of heat is pretty rare and the impacts are going to be definitely felt by the public,” Deemer said.

In California on Monday, the summer solstice pushed records there to the brink, too. In Palm Springs, just southeast of Los Angeles, temperatures reached 122 degrees early Monday afternoon. That’s just one degree short of the all-time record of 123 degrees set in July of 1995, according to the Desert Sun.

Across The Globe, Wildfire Season Is Lasting LongerClimate by CREDIT: Shutterstock With 35 active large fires currently burning up and down the West Coast – and with dry…thinkprogress.orgAs of press time, at least four heat-related fatalities have been reported in separate incidents in Arizona. All were hikers and one was a personal trainer who died of heatstroke despite having plenty of water on her, tragic proof of how powerful the desert heat has been in the past couple of days.

Meanwhile, evacuations are in place as at least five wildfires boosted by triple-digit weather are burning thousands of acres in multiple states, including New Mexico, Arizona, and California, according to published reports. In Santa Barbara, a wildfire grew to cover nearly 8,000 acres though it’s more than 50 percent contained, according to authorities. Some 200 miles south, a number of schools in east San Diego County are reportedly closed and evacuations are ongoing while hundreds of firefighters attempt to control blazes now ravaging a dry mountainous area on both sides of the U.S.-Mexico border.

While emergency personnel push to control fires and officials call for people to stay out of the heat, experts said what’s happening now is but a glimpse of what global warming is doing to the world’s summers. Indeed, recurrent record hot summers will almost certainly be the norm in the coming years, according to a study from the National Center for Atmospheric Research, or NCAR, published last week. The study found an 80 percent probability that any summer between 2061 and 2080 will be warmer than the hottest on record across the world’s land areas unless greenhouse gas emissions decrease.

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In addition, in large parts of North and South America, central Europe, Asia, and Africa the probabilities are 90 percent or higher, said Flavio Lehner, lead author and post-doctoral researcher at NCAR. This means virtually every summer will be warmer than the warmest during the period of 1920 through 2014. If emissions decline this probability drops in most areas, Lehner said. Otherwise in some areas “we can basically plan [for] these very hot summers every year.”

In reaching their conclusions, scientists evaluated two scenarios. One was a business as usual scenario called RCP 8.5, which assumes high population, high energy demand, and unabated green house emissions. “That means emissions are continuing at the rate that they are at now,” he said. The second scenario, RCP 4.5, assumes global warming policies that produce moderately lower emissions and other climate mitigation policies.

The business as usual scenario on the top left shows an overwhelming probability that a given summer during 2061–2080 will be warmer than the warmest on record during thehistorical period 1920–2014. Top right shows overall improvement if greenhouse gas emissions moderately decline. Thestippling in (c) indicates areas that see a risk of 90 percent or more already under some emissions mitigation. CREDIT: Future risk of record-breaking summer temperatures and its mitigation study
The business as usual scenario on the top left shows an overwhelming probability that a given summer during 2061–2080 will be warmer than the warmest on record during thehistorical period 1920–2014. Top right shows overall improvement if greenhouse gas emissions moderately decline. Thestippling in (c) indicates areas that see a risk of 90 percent or more already under some emissions mitigation. CREDIT: Future risk of record-breaking summer temperatures and its mitigation study

After recreating thousands of past and future summers, researchers found that reducing emissions would lower the global probability of record hot future summers by at least 40 percent. However, probabilities don’t drop uniformly across the globe. In some regions, including the East Coast, northeastern Africa, Indonesia, parts of China, and large parts of the tropics, the probability remains over 90 percent since these areas warm up even under moderately lower emissions, according to the study.

The global consensus set in the Paris climate accord tries to limit warming to 2 degrees Celsius, but some researchers and advocates have said the most vulnerable regions require a 1.5 Celsius threshold.

Still, Lehner noted that areas benefiting the most — including central Europe, parts of Brazil, and southeast China — are among the most densely populated. “Humans benefit disproportionately from [emission] reductions,” said Lehner. He also explained that under the business as usual scenario the southwest is poised to heat up substantially. In Phoenix, summers could be up to 9 degrees Fahrenheit higher than normal. “Warming is quite tremendous in those regions,” he said about potential warming for the southwest.

Southwest And Great Plains Could Face Worst ‘Megadroughts’ In Modern History, Study FindsClimate by CREDIT: Shutterstock A new study that builds upon recent research predicts that in the second half of the…thinkprogress.orgThe higher temperatures as projected by the NCAR study and others become a daunting problem for the arid southwest, a region already prone to droughts. In 2015 a study from Columbia University’s Lamont-Doherty Earth Observatory found that the Southwest and Great Plains will in the second half of the 21st-century experience drought conditions worse than those documented in ancient and modern times.

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Increasing temperatures would only make any drought worse, Lehner said, but noted emissions reductions would make a substantial difference in reducing dangerous warming. “This risk can really be cut in half with these moderate mitigations,” he said while referring to policies that promote less greenhouse gas emissions. “Even moderate mitigation has a clear benefit.”

Whether the world will aggressively pursue in the coming years the emission reductions to avert the dramatic warming Lehner’s study projects remains to be seen. Countries are ratifying the Paris accords, but in the United States, a political battle continues as to whether to pursue emission reduction policies like the Clean Power Plan, which calls for reductions in carbon emissions from the electricity sector by 32 percent over 2005 levels in the next 15 years. In the meantime, “the rate of record-breaking temperatures is indeed increasing,” Lehner said, adding that delays could force the world to forgo mitigation to focus instead on adaptation. “And I think that’s when it starts being very complicated.”

That’s because adaptation is costly. The United Nations estimated that adaptation costs for developing countries could be as high as $500 billion every year by 2050, a full decade before the NCAR study projected record warming summers to become the new normal.

Yet despite the risks of warming, Arizona’s leaders have tried to block the Clean Power Plan, even as 2,000 Arizonans visit the ER due to heat-related illnesses each year. The sun-drenched state’s utilities have also put roadblocks in front of solar energy development by proposing so-called demand rates that reduce the financial incentive to install solar panels — which have caused layoffs in the state’s fledgling solar industry.