It looks like we’re in for a strong, lengthy El Niño this year.
Warmer-than-usual water in parts of the Pacific Ocean indicates that a developing El Niño is intensifying and might become one of the strongest on record. And National Oceanic and Atmospheric Administration scientists think the weather phenomenon probably will continue through the winter of 2015-16, and into the spring of 2016.
El Niños have been occurring at least since the end of the last Ice Age about 10,000 years ago. But scientists have only been able to effectively monitor the events since the advent of weather satellites. In that time, there have only been two strong El Niños—one in 1982-83 and another in 1997-98.
Given the lack of past data, precise predictions can be difficult. And it's too early to tell whether this El Niño will set any records. But meteorologists say the list of possible effects is unsettling and includes torrential rainfall and flooding in some places, drought in other areas, powerful hurricanes in the Pacific, and winter tornadoes in Florida and the U.S. Southeast.
El Niño has already made this summer a stormy one in the Pacific. Eight tropical storms have formed since mid-May, and three of those have become very powerful hurricanes with winds exceeding 130 miles per hour (209 kilometers per hour).
The warmer water usually fuels powerful winter thunderstorms in North America and South America. So the developing El Niño could bring badly needed rain to California later this year. But that carries a risk. The 1982-83 event caused flooding in California and the southern U.S., and the 1997-98 El Niño caused deadly flooding in Peru and Ecuador.
Ecuador and northern Peru also saw heavy rains in 1982-83. The rain spurred plant growth, which attracted swarms of grasshoppers. That was followed by a surge in toad and bird populations. The wetness caused a huge increase in mosquitoes and, subsequently, an uptick in malaria.
But it’s not all storms. The 1997-98 El Niño led to a severe drought in Indonesia, along with unusually high temperatures. Huge forest fires there burned an area larger than the state of Indiana, says Jeff Masters, meteorological director for the website Weather Underground.
If there’s a silver lining to a powerful El Niño, it's that the activity usually increases upper-level winds over the Atlantic Ocean. This makes it much more difficult for hurricanes to form in the Atlantic. So far this summer, the Atlantic hurricane season has been relatively quiet.
Concern for Fish
A powerful El Niño could affect fish and wildlife. When the warming waters in the equatorial Pacific set an El Niño into motion, the prevailing east-to-west winds relax and even reverse. Warm water then moves eastward over the ocean.
The warmer water disrupts the normal upwelling of nutrients from cooler depths, and that “messes up the food chain in the ocean,” says meteorologist Stanley Goldenberg at NOAA’s Hurricane Research Division in Miami. “It tends to almost wipe out anchovy fishing. That’s not a big deal to people who don’t like anchovies on their pizza, but anchovies also provide the fish meal that is used to feed livestock. So it has a ripple effect.”
Anchovies also are a major food source for many other fish, seabirds and marine mammals.
This year, there’s concern that unusually warm water off the Peruvian coast has already cut off the flow of nutrients. That will diminish the catch of commercial fishermen, sending a shock through Peru’s economy. And Peruvian officials have declared a state of emergency in expectation of heavy rainfall and flooding this winter, Weather Underground’s Masters says.
The reversal of prevailing winds can also cause sea levels to rise in the eastern Pacific and drop elsewhere. During the 1982-83 El Niño, the rise caused seabirds on Christmas Island to abandon their young. Fur seals and sea lions died, and fish from Chile to British Columbia left in search of more temperate waters.
The drop can expose the tops of coral reefs. Most of the reefs around the Galapagos Islands were killed during the 1982-83 El Niño.
Officials in Hawaii are very worried that the current El Niño could cause a massive die-off of coral there.
More to Study
Scientists aren’t sure whether human-induced climate change will be a factor in the developing El Niño. “That’s a big question,” says Neal Dorst, a meteorologist at the Hurricane Research Division. “We don’t have a long enough record of El Niños.”
Nor do they know whether the global sea level rise might become a factor.
Masters says climate change “could lead to some surprising effects,” but it’s hard to predict what those effects might be, or even if they will occur.
Water temperatures off the coast of California and Mexico are the warmest on record, Masters says, and that eventually could produce powerful rainstorms that will cause flooding worse than that seen during earlier El Niños. And a warmer winter could reduce snowfall in the Sierra Mountains, meaning there would be less snowpack during the spring melt that normally provides irrigation and drinking water.
Still, the El Niño’s effects will end eventually.
“It is stressful on animals and plants,” said Dorst. “It’s altering their ecological conditions, the warmth of the water and the amount of rain. But it’s short-lived. Things go back to normal conditions, and they recover.”
And when it’s over, scientists will have a third strong El Niño to help improve their predictions for the fourth.
North Carolina author Willie Drye’s latest book, For Sale—American Paradise, will be published October 1 by Lyons Press.