Two faraway corners of the world, known for their temperate climates, are struck by deadly disasters. Wildfires have killed more than 120 people as they sweep Chile’s forested slopes, and record-breaking rainfall has swollen rivers and triggered mudslides in Southern California.
Behind these risks are two powerful forces: climate change, which can intensify both rain and drought, and the natural weather phenomenon known as El Niño, which can also outweigh extreme weather events.
In California, forecasters had warned for days that an unusually strong storm, known as an atmospheric river, was gathering strength due to extremely high temperatures in the Pacific Ocean. The rains started over the weekend and several counties are under a state of emergency. By Monday, officials warned that the Los Angeles area could be inundated with the equivalent of a year’s worth of rain in a single day.
In the southern hemisphere, Chile has been suffering from drought for the better part of a decade. This set the scene for an infernal weekend when, amid intense heat, fires broke out. The president has since declared two days of national mourning and warned that the death toll from the devastating fires could “rise significantly”.
Both the floods and wildfires reflect extreme weather hazards caused by a dangerous cocktail of global warming, caused primarily by the burning of fossil fuels, and this year’s El Niño, a cyclical weather phenomenon characterized by warming of the Pacific Ocean near Equator.
Disasters in Chile and California follow hottest year on land and oceans. They herald what is almost certain one of the five hottest years on record, according to the National Oceanic and Atmospheric Administration.
“These synchronized fires and floods in Chile and California are certainly a reminder of extreme weather and its effects on otherwise benign Mediterranean climates,” John Ambatzoglou, a climatologist at the University of California, Merced, said in an email. . Climate variables, along with the effects of El Niño, are “the main instruments in the orchestra for single extreme events,” he said, “with the drumbeat of climate change beating louder and louder as the years go by.”
In California’s case, unusually warm temperatures in the Pacific Ocean have outpaced atmospheric river storms that began Saturday and are expected to continue for at least another day. Parts of the Santa Monica Mountains recorded more than seven inches of rain over the weekend, triggering mudslides in some of Los Angeles’ wealthiest neighborhoods.
Up to 14 inches of rain could fall Monday in parts of the region, which would be close to the annual rainfall average. City and state officials urged people to stay off the roads. Showers could peak around evening commute time.
The two disasters highlight what some experts call an underestimated risk of climate change. While significant money and attention has gone into preparing for California’s drought, the chances of more severe storms also increase in a warming climate. “We’re not really ready,” Daniel Swain, a climate scientist at the University of California, Los Angeles, said Monday morning in a video he posted online.
“We have neglected to seriously consider large plausible increases in flood risk in a warming climate,” he said.
Brett F. Sanders, an engineering professor at the University of California, Irvine, who focuses on flood management, said atmospheric rivers like the one hitting the state now have been predicted by climate models and present urban planners with new challenges.
“The mindset of the past was that we could control flooding and contain flooding. And besides, communities, businesses and residents could do what they do and not think about flooding,” Dr Saunders said. “But we know now that, around the U.S., we’re seeing less infrastructure to contain today’s extreme weather.”
Chile is under extreme fire weather conditions as an unrelenting drought for much of the past decade has dried up forests and depleted water supplies. Over the weekend came a strong heat wave that also bore the fingerprints of an El Nino period. During an El Niño, warmer-than-usual ocean temperatures in parts of the Pacific can affect climate patterns worldwide, increasing rainfall in some places and exacerbating drought elsewhere.
It didn’t help that, in heat- and drought-stricken areas of Chile, there are large monoculture plantations of highly flammable trees near cities and towns. When a fire broke out, strong, hot winds fanned the flames quickly. Aerial video showed cars and houses in one of the country’s most popular tourist destinations in the Valparaiso area burning to the ground.
Chile is no stranger to wildfires during the hot summer months. An estimated 1.7 million hectares have burned in the past decade, triple the area burned in the previous decade. ONE recent study published in the journal Nature found that “the coincidence of El Niño and climate-fueled drought and heat waves enhance local fire risk and have contributed decisively to the intense fire activity recently seen in Central Chile.”
The government increased funding for firefighting this year. It was insufficient to prevent the country’s worst wildfires in a decade.
Sarah Feron, one of the authors of this study, saw it as a sign of things to come. “In some areas of the world, we are facing climate-fueled disasters for which we are unprepared and unlikely to be able to fully adapt,” he said.
Raymond Zhong contributed to the report.