Heat, Floods, Fire: Was Summer 2023 the New Normal?

Climate scientists have a message about this summer’s wild weather: Get used to it.

The wildfires, flooding and heatwaves will get worse and happen more often—and affect more people, they say.

“There isn’t really a new normal yet,” said Rachel White, an atmospheric scientist and assistant professor at the University of British Columbia. “What we’re experiencing right now is probably just a stopover on our way to the new normal.”

Decades of pumping greenhouse gasses into the air is heating the planet, climate scientists say, making wildfires burn farther, storms grow stronger and heat waves last longer.

A warmer planet doesn’t just mean extreme heat, said Michael E. Mann, a professor at the University of Pennsylvania and the director of the Penn Center for Science, Sustainability and the Media.

The heat dries out soil, worsening summer droughts. Heat and drought is a recipe for intense wildfires. And as the atmosphere warms, it holds more water, leading to heavier rainfall and floods. In addition, the jet stream—a narrow band of strong, high-altitude winds separating warm and cold air—has slowed during the summer as the Earth’s poles warm. That is causing persistent weather extremes, such as longlasting droughts and fires, Mann said.

Some of these extreme weather events have hit parts of the world where they are historically rare, in aberrations that scientists say could become more common.

July was the Earth’s hottest month on record. And 2023 is on track to become the hottest year in history, according to the National Oceanic and Atmospheric Administration.

Heat

Heat waves in the summer aren’t new. But here’s what is: heat waves with record-high temperatures that last for days or longer, said Akshay Deoras, a meteorologist at the University of Reading in England.

China set a new national record last month, when temperatures climbed to 126 degrees Fahrenheit in the northwest of the country. Phoenix had a record 31 straight days of temperatures above 110 degrees in July, beating a 1974 streak of 18 days. In Europe, heat waves are expected until the end of August.

Natural variability in the Earth’s climate means some years will be hotter or cooler than others. With the combination of climate change in those hotter years, “you get really intense conditions,” White said.

The long stretches of warm weather are affecting everything from food production to everyday activities. Farmers in Italy are growing mangoes, bananas and other tropical fruits. In the U.S., people are running errands after the sun sets, when it’s cooler.

Wildfires

The blistering heat has helped worsen drought conditions around the globe, stoking fires in Greece, Spain, the U.S. and Canada.

A team from World Weather Attribution, a group of climate scientists based in London and the Netherlands, found that fire weather—a composite measure of temperature, rainfall, wind and humidity that influences the spread of wildfires—has been boosted by underlying climate warming.

The researchers focused their analysis on the conditions and fires this year in Quebec, which contributed to the heavy plumes of smoke that blanketed a huge swatch of the Eastern U.S. in June.

Their study found the weather conditions that spawned the record-breaking Quebec fires were twice as likely to occur and up to 50% more intense as the result of climate warming.

Quebec experienced less snow cover, which usually blankets the ground and tamps down potential fires, as well as severe drought conditions, said Yan Boulanger, research scientist at the Canadian Forest Service. May and June broke the previous national temperature record for the two-month period by 1.4 degrees Fahrenheit and fueled the spread of wildfires.

By taking the observed weather conditions and feeding them into existing climate models, the scientists found that fire weather “is becoming more severe and more likely as the globe warms,” said Clair Barnes, research associate at the Grantham Institute, Imperial College London, who was part of the research team.

More than 5,800 fires in Canada scorched 34.6 million acres this summer, nearly double the previous record from 1989, according to Boulanger.

The blazes have forced thousands to evacuate their homes. In June, a town of 16,000 in the suburbs of Halifax, Nova Scotia, was asked to leave due to fires. Last week, residents in Yellowknife, a town of 20,000 people in Canada’s Northwest Territories about 300 miles south of the Arctic Circle, had to flee.

In Hawaii, drought, gusty winds and an overgrowth of invasive grasses and shrubs helped fuel the deadliest U.S. wildfire in more than a century. Flames destroyed Lahaina, the former capital of the Hawaiian Kingdom, located in one of Maui’s most fire-prone areas. At least 115 people died, and hundreds are still missing.

Flooding

As the Earth’s atmosphere warms, it holds more water vapor, leading to heavy rainfalls that can cause catastrophic flooding, said Mohammed Ombadi, a climate professor at the University of Michigan.

Every 1 degree Celsius the Earth’s atmosphere warms, it can hold 7% more moisture, according to the National Aeronautics and Space Administration.

Last month, the worst floods in a century hit Vermont’s capital city of Montpelier. Homes, businesses and critical infrastructure were destroyed across the state. Rescuers raced to save stranded residents.

In China, torrential rains from Typhoon Doksuri caused the deadliest flooding in a decade in the Beijing area. While tropical storms frequently hit the country’s coastal regions, the extent of the rainfall and flooding from Doksuri was unusual.

The remnants of Hurricane Hilary, meanwhile, dropped record amounts of rain on Southern California over the weekend, flooding roads in typically dry Palm Springs. Hilary was the first tropical storm in nearly a century to hit the region.

Fuente: The Wall Street Journal