The big idea
Days of extreme high heat and extreme air pollution are both increasing worldwide. In November 2019, New Delhi experienced a week of the worst air pollution in human history. The entire city shut down and planes couldn’t see well enough to land. Not long before that, Western Europe was slammed with two record-breaking heatwaves that caused the deaths of nearly 1,500 people.
Days of extreme heat and extreme pollution do not often overlap, but our two teams at Texas A&M wanted to see if the number of these double extreme days was increasing and explore what the health risks of that might be.
To test this, we used a computer model to look at the co-occurrence of extreme heat and extreme air pollution in South Asia. The model incorporated trends in greenhouse gas and air pollution emissions from industrial and residential sources, population growth, migration trends and even how air pollution is affected by weather, terrain and nearby oceans.
We predict that the frequency of days with both extreme heat and pollution – and the number of people that will be affected by those days – could massively increase by 2050.
We focused on South Asia because it’s already a climate change hot spot and its population is projected to increase from 1.5 billion today to 2 billion by 2050. Under a worst-case climate change scenario and with little reduction in CO2 and other pollutants, days with both extreme heat and extreme pollution would increase in frequency by 175% in the region, resulting in roughly 78 days a year with those double whammy conditions.
Additionally, the amount of land that would experience this double threat for 60 days or more a year would increase tenfold from 2000 to 2050 – from 2% to more than 25% of all of South Asia. This will also lead to more than 52% of the population being exposed to more than 60 days of this double hazard.
Why it matters
Both extreme heat and air pollution have severe negative effects on the human body.
Extreme heat increases the likelihood of heat exhaustion and heat stroke, but can also worsen chronic ailments such as heart disease. As part of an effort to better understand how extreme heat affects mortality rates, we are currently studying the health effects of heat extremes here in Texas.
So what happens when a person experiences both at the same time?
Scientists know that when a person experiences air pollution in addition to another simultaneous stressor, they become more susceptible to both. This has been shown for combinations such as air pollution and smoking, as well as air pollution and COVID-19.
It is hard to say exactly what effect a prolonged exposure to the double threats of heat and air pollution would have on human health as there have only been a few cases studies looking at the combined effects of both. The results, though sparse, do suggest that more people die when the two conditions co-occur.
What still isn’t known
The full health effects from a combination of extreme heat and extreme pollution are largely unknown, especially in many developing nations where studies haven’t been done and the extremes are expected to get more severe. Billions of people are expected to experience these conditions in the coming decades, but researchers know little about what the risks are.
Which populations – both demographically and in terms of chronic diseases – are most at risk? Just how dangerous are these double extreme days to human health? Where are the most at-risk populations?
It is thus important to develop an empirical understanding of the relationship between health outcomes and multiple environmental stressors like heat and air quality.
Learning who is most at risk is important, but taking preventative measures, everyone together, should also be considered.
Using our models, we found that reducing carbon dioxide and non-CO2 air pollutant emissions – even by a moderate amount far less than what would be required to meet the 2 degrees Celsius target in the Paris agreement – would prevent the most severe outcomes.
Even under a very moderate emission reduction scenario called RCP6.0 – where emissions peak in 2060 – the frequency of double extreme days would increase by only 58% by 2050, compared to the 175% we are headed for. The population and land area to experience extended exposure to this hazard would be less than half of what was projected in the business-as-usual scenario.
These increases are still nothing to look forward to, but they show that mitigation efforts can make a big difference. In our view, the world needs to act swiftly and, for example, seize the opportunity of current economic recovery to invest in greener energy. Our future generations do not deserve a dirty, hot future.
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This article is republished from The Conversation, a nonprofit news site dedicated to sharing ideas from academic experts. It was written by: Yangyang Xu, Texas A&M University and Xiaohui Xu, Texas A&M University.
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Yangyang Xu receives funding from National Science Foundation.
Xiaohui Xu does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
Minnesota wildfire doubles in size, creates its own weather
A wildfire in northeastern Minnesota more than doubled in size Tuesday, growing to more than 19,000 acres, after it produced pyrocumulous clouds that generated lightning and even raindrops, fire officials said.
The Greenwood Fire’s growth, most of which happened Monday afternoon, prompted firefighters to leave McDougal Lake, about 80 miles south-southwest of Duluth, officials said. Authorities fear that structures might have been destroyed or damaged.
“We had crews embedded, and as this fire took off, it was quite an effort to communicate with forces on the ground so they could get out,” said federal fire incident spokesman Clark McCreedy.
The pullout was a success, and no injuries were reported. However, downed trees and necessary cleanup mean crews have been unable to assess damage around the lake, McCreedy said.
In addition to the firefighter pullout, 159 dwellings were evacuated Monday, according to an update from the National Wildfire Coordinating Group. Cabins, homes and recreational sites remain under threat, the group said.
Patrick Prochaska, a Minneapolis resident who built a cabin near McDougal Lake in 2012, told NBC affiliate KARE that he watched via security camera as flames mostly bypassed his property Monday, causing minor damage.
“I was feeling very scared,” he said. “At the same time, I could see that it was not doing anything to the house, and it was kind of reassuring.”
The fire in and north of Superior National Forest has mostly performed according to the weather, fire officials said. On Monday, with dry fuel on the ground and temperatures in the high 80s, it was an expanding inferno punctuated by strobes of lightning.
“The winds were drawn into the fire from all directions,” the incident’s fire behavior analyst, Michael Locke, said in a video update Tuesday. “It created what we call pyrocumulous clouds. And really high in the atmosphere … you’d see a thunderstorm, and in fact they went high enough to produce a few sprinkles of rain and even some lightning.”
Temperatures dipped into the mid-70s Tuesday, and the blaze mellowed. “The real story was cloud cover and cooler temperatures,” McCreedy said.
More of the same, and possibly rain, was in the forecast, giving officials hope that they might be able to close the book on an unusually active and dry fire season in Minnesota.
Experts have said climate change has set the stage for extreme weather, including an increase in the frequency and intensity of wildfires in the Northern Hemisphere.
Firefighters — 426 were assigned to the Greenwood event — have been confronted with “prolonged, severe drought,” making parts of Minnesota look like the fire-prone West this summer, McCreedy said.
The Greenwood Fire, which was detected Aug. 15, is believed to have been sparked by lightning.
So far, firefighters have scored no containment, and areas including McDougal Lake, Sand Lake and the Highway 2 corridor have been under mandatory evacuation orders. The federal Boundary Waters Canoe Area Wilderness was closed Saturday “due to active and increasing fire activity, extreme drought, limited resources,” the National Forest Service said in a notice.
Officials set a goal of Sept. 1 for full containment.
“We’re probably going to get more of that moderating weather for the rest of the week,” McCreedy said. “That opens the door for fire crews to make progress on the ground.”
Hiker survives grizzly bear attack at Denali National Park
A tourist from Indiana was attacked and injured by a grizzly bear at Denali National Park and Preserve in Alaska on Monday night, park officials said.
The 55-year-old tourist, whose name was not released, was hiking alone in dense fog in the Thoroughfare Pass area when a mother bear and multiple cubs charged him from nearby bushes, the National Park Service said in a statement Tuesday.
He had puncture wounds to a calf, his left ribs and his left shoulder, the agency said.
The victim used bear spray that might have cut the attack short, the park service indicated. He walked 1.5 miles to a visitor’s center where “medical personnel” vacationing at Denali treated him as a park bus driver called 911, it said.
The hiker was taken to a medical center near the park before he was transferred to Fairbanks Memorial Hospital, about 120 miles away, park officials said. He was stabilized at the Fairbanks hospital, they said.
“Due to the apparent defensive nature of this attack, there are no plans to locate the bear involved,” the park service said. “Female bears with cubs are naturally defensive of their young, especially when surprised. There is no indication that this bear is unusually dangerous.”
Grizzly bears are federally protected as a threatened species in the lower 48 states. According to the National Wildlife Federation, fewer than 1,500 grizzlies are left in the lower 48, but they thrive, comparatively, in Alaska, where they have a population of about 31,000.
The backcountry area of the attack is closed for one week as a precaution, the park service said.
House passes John Lewis voting rights bill, sends measure to Senate for tougher fight
House Democrats on Tuesday passed a sweeping voting rights bill named after Rep. John Lewis, D-Ga., the late civil rights icon.
The John Lewis Voting Rights Advancement Act was approved 219-212. All Republicans voted against the legislation.
The bill is part of congressional Democrats’ broader campaign to strengthen voting laws at the federal level to fight restrictive voting laws passed in Republican-led states, such as Texas and Georgia. However, it faces steep opposition in the Senate, where Democrats hold a wafer-thin majority.
The House returned from its recess this week to take up the bipartisan infrastructure bill and a resolution for Democrats’ $3.5 trillion budget package, which includes funding for much of President Joe Biden’s legislative agenda. The procedural motion used to pass the multitrillion-dollar resolution paved the way for the House to vote on the voting rights bill, which was re-introduced last week by Rep. Terri Sewell, D-Ala.
The legislation would require states with recent histories of discrimination to get federal “preclearance” to change their voting laws, which directly addresses the Supreme Court’s 2013 ruling in Shelby County v. Holder. The ruling gutted the preclearance system in the Voting Rights Act of 1965, which civil rights advocates argue was successful in blocking proposed voting restrictions in states and localities with histories of racial discrimination.
House Speaker Nancy Pelosi, D-Calif., said in a statement last week that Congress had “not only an ironclad Constitutional mandate, but a moral responsibility” to pass the bill.
Shortly before its passage, Pelosi said on the House floor that the bill would honor Lewis’ legacy.
“We should have the right to vote and shouldn’t be diminished by anyone. It is unpatriotic to undermine the ability of people who have a right to vote, who have access to the polls,” she said. “As John knew, this precious pillar of our democracy is under attack from one of the worst voter suppression campaigns since Jim Crow.”
It isn’t the first time House Democrats have tackled election law. In March, House Democrats passed the For the People Act, a sweeping bill that seeks to change campaign finance, voting and ethics laws.
The bill would expand access to the ballot box by creating automatic voter registration across the country by registering eligible voters whenever they interact with government agencies, restoring the voting rights of the formerly incarcerated, expanding early voting and modernizing the country’s voting systems.
However, Senate Republicans filibustered the voting rights legislation in June, and the vote to advance an amended version of the For the People Act split along party lines 50-50, short of the 60 votes needed. All Democratic-aligned senators voted to begin debate, and Republicans unanimously voted to block the bill.
Passage of the voting measure was the final vote of the week for the House, whose members are leaving Washington and won’t return until Sept. 20.
Haley Talbot contributed.
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