Harsh weather doesn’t end with summer

On Labor Day, you can drive from Minnesota’s border with Canada all the way to where Louisiana hits the Gulf of Mexico and never experience a high temperature below 90 degrees. The heat isn’t over yet: Today, nearly one-third of Americans experience extreme heat under heat alerts.

Such weather is a fitting end to a devastating season, the kind that runs out of superlatives. This summer, extreme weather events suddenly seemed to be everywhere, all at once. It was the world’s hottest June since humans began tracking it. July was even worse. Phoenix – which middle 102 degrees in July – it got so hot that people got third degree burns from touching door handles. In Iowa, cattle fell dead in their barns. Disasters were not limited to heat: Canadian wildfires covered large areas of the United States in smoke, flash floods shook Vermont, and wildfires turned parts of the island of Maui into ruins.

Pumpkin Spice is already back on the Starbucks menu, but fall isn’t ready to provide a break. El Niño, the warm phase of a naturally recurring cycle that can wreak havoc on global weather patterns, is officially back, and it’s expected to be strong. The southern United States is likely to be wetter, while forecasts indicate a warm winter in the north. These cycles always have some fluctuations, but experts say the climate crisis has now caused temperatures to rise to the point that El Niño may also be amplified. This summer has starkly demonstrated how climate change can make weather even more powerful. This fall, the El Niño phenomenon may exacerbate the problem.

Although El Niño technically began in June, it likely did not contribute much to extreme events this summer. That was the climate crisis. Across the United States, hundreds of record-setting temperatures were set. The heat index in Kansas City approached that of Death Valley. Chicago had to reduce the speed of its trains because high temperatures stressed the tracks. “Historically, El Niño events during the summer have had very little impact on the United States,” Michele L’Heureux, a climate scientist at the National Oceanic and Atmospheric Administration, told me. “However, climate change is having an impact.” Scientists were once reluctant to talk about how global warming might make weather worse. They can now accurately measure how climate contributes to events such as heat waves. An international team of researchers found that climate change made July heat waves in the United States, Europe and China hotter by up to 2 degrees Celsius, or 3.6 degrees Fahrenheit, as a result of climate change.

After the extreme conditions of this summer, it is difficult to reach the peak of the El Niño cycle. Normally, because of the direction in which the world rotates, winds move from east to west across the tropics. This pushes warm surface waters away from South America, where colder waters swell to replace them. But every two to seven years, these winds weaken and more warm water stays along the Americas, creating the El Niño phenomenon. (When the winds get stronger, you get its counterpart, La Niña.) The Pacific Ocean is huge, covering a third of the Earth’s surface, so these cycles can cause huge changes in global storms and droughts. That’s why L’Heureux calls El Niño the “big push.” As she explains: “It pushes atmospheric patterns around the world in certain directions that cause weather patterns to repeat.”

Unlike during La Niña, when cooler oceans can absorb more heat, El Niño essentially acts as a temporary boost to global warming — raising global temperatures by about a tenth of a degree Celsius, or roughly 0.2 degrees Fahrenheit. However, the effects vary by location: some places become colder, while others become warmer. For example, a strong El Niño event during the winter of 1997-1998 caused floods in California, while Indonesia and the Philippines experienced severe drought. In 2016, another El Niño record contributed to what remains officially the world’s warmest year on record; The National Oceanic and Atmospheric Administration (NOAA) estimates it raised the annual global temperature 0.12 degrees Celsius, or 0.2 degrees Fahrenheit, above average.

The impact of El Niño is also likely to increase due to climate change. Warmer air holds more moisture, setting the stage for more intense precipitation; Likewise, higher temperatures may exacerbate the drought conditions they already tend to bring to some locations. “The effects of El Niño no longer operate in isolation. There is always a climate component,” L’Heureux said.

Unless you’re a mosquito in New Mexico, this isn’t good news for the fall and winter. Currently, satellites, sensors and models indicate that ocean temperatures are gradually increasing, as the circulation gains strength. The effects of El Niño will be most noticeable later this fall and into the winter of 2024. (This phenomenon is called El Niño, or “the little boy” in Spanish, after the birth of Christ, because the cycle tends to peak at Christmas.) The southern United States will likely see wetter conditions. Meanwhile, the Pacific Northwest is expected to be drier, while the northern part of the country may have a mild winter. “Because it’s a climate forecast, and we can’t say anything definitively, we put probabilities on everything,” Loro said.

Based on past El Niño events, the United States may experience more extreme weather events. In 1997-1998, for example, California experienced 150% of its normal rainfall, washing out roads and causing deadly mudslides that destroyed homes. There was practically no winter in the Midwest, with some areas seeing average temperatures 12 degrees warmer than a normal year. Some may rejoice in a milder fall and winter, but that may also increase the risk of alarming temperatures in September and October. Warmer temperatures could set the stage for worse wildfires next summer. Not to mention all the other downstream effects of throwing normal patterns out of control. In 2016, for example, a cool, wet spring was great for fleas and other disease-carrying insects, which led to increased cases of plague and West Nile in the Southwest. Going back to 1982 and 1983, unseasonal heat in Alaska was likely behind the decline in salmon yields, while warmer waters caused a rash of shark bites off the Oregon coast.

Of course, El Niño is not just a problem specific to the United States. As with climate change, developing countries are often the most affected. Petteri Taalas, Secretary-General of the World Meteorological Organization, warned that as a result of the El Niño phenomenon, the coming months could have “far-reaching implications for health, food security, water management and the environment.” The total heat could push global temperatures beyond the notorious benchmark — 1.5 degrees Celsius warmer than the pre-industrial era, surpassing records set during the last El Niño in 2016.

L’Heureux leads the El Nino-Southern Oscillation team in NOAA’s Climate Prediction Center and its team predict that El Niño has a more than 95% chance of continuing through February 2024. After that, it’s hard to say. El Niño typically lasts for about a year, but the exact timing and intensity of each cycle can vary. In a warmer future, El Niño may extend for a longer period. newly nature The paper notes that there is some early evidence that the transitions between El Niño and La Niña phases may be slowing, meaning the associated conditions could persist. The Pacific circulation, a huge atmospheric ring over most of the tropics, helps determine these shifts, and many models predict that climate change will weaken this ring. As a result, “instead of single years of El Niño or La Niña conditions, we may see more multi-year events,” says Georgina Falster, lead author of the study. Think extended droughts, and more summers with heat waves that last for weeks.

These are complex systems, and many parts of the El Niño cycle are still not well understood. But knowing how these cycles change is important, because climate models rely on our best attempts at description Present conditions in order to make assumptions about how the world will change. If the assumptions are not accurate, they could change our expectations of climate impacts. “There’s a lot of uncertainty” about these models, Lorioux said. This applies to the way we confront climate change as well. The weather in any given year can be extremely variable, a point that Sen. James Inhofe’s snowball inadvertently made to Congress. Climate change may not always seem linear, and last summer, its effects appeared to be progressing rapidly. A hot winter, partly fueled by El Niño, does not necessarily mean next summer will be worse. But in the long term, the trend toward warming is non-negotiable.

Disturbingly, all of this is still just an introduction to a world that looks very different from the one we have known so far. Allegra LeGrande, a research physicist at NASA’s Goddard Institute for Space Studies, told me that when her young children reach their 40s, “they won’t have as cold a summer as I do.” Although researchers have been predicting dire climate consequences for decades, many scientists I spoke with this summer grappled with how to feel about the latest drumbeat of broken records. For her part, LeGrande has been coping by overindulging in survival shows like Single that drops contestants into the wilderness to see how long they can withstand the elements – a cinematic version of the altered reality that many have already begun to encounter off-screen.

No matter how much you study or read about the climate crisis, it hits differently when you have to confront it every time you walk outside. After this summer’s strangeness, the science may be complicated, but the conclusion is simple: Even when El Niño dissipates and the world returns to a cooler phase, it will not be enough to counter the march toward a warming Earth. Only we can do that.

(tags for translation) El Niño phenomenon

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