El Niño conditions have developed in the tropical Pacific for the first time in seven years, according to the World Meteorological Organization, leading to a possible surge in global temperatures.
The WMO made the declaration Tuesday, several months after saying there was a high chance of the phenomenon developing this year.
The organization expects the event to be at least of moderate strength, but even a moderate El Niño could increase the likelihood of breaking temperature records and triggering more extreme heat in many parts of the world and in the ocean, according to WMO secretary-general Petteri Taalas.
“The declaration of an El Niño by WMO is the signal to governments around the world to mobilize preparations to limit the impacts on our health, our ecosystems and our economies,” he said in a statement. “Early warnings and anticipatory action of extreme weather events associated with this major climate phenomenon are vital to save lives and livelihoods.”
Armel Castellan, a meteorologist with Environment and Climate Change Canada, said the El Niño is expected to affect B.C. in December and will likely mean a milder winter.
He said the summer and fall in B.C. are forecast to be hotter and drier than normal but that’s not because of El Niño.
“They’re just a result of sea surface temperature anomalies right across the Northern Hemisphere. In particular in the Pacific, where of course we get most of our weather from west to east,” he said.
However, as El Niño continues, he said there is a high probability that B.C. could see conditions similar to 2016 — the world’s hottest year on record — when warmer temperatures coincided with a strong El Niño.
The concern is that a strong El Niño could create what the WMO calls a “double whammy,” where a powerful event is combined with human-induced climate change from greenhouse gases causing record temperatures.
In 2016, B.C. had a temperate winter with freezing levels much higher than normal, causing a bleak ski season for lower elevation areas like Vancouver.
Castellan said El Niño events do cause warmer temperatures but aren’t necessarily wetter or drier than normal, and meteorologists can’t yet predict how much warmer it will be this winter. This is because it depends on whether it’s a moderate or strong El Niño, and those ratings relate to how strong the sea surface temperature anomaly is in that particular region in the equatorial Pacific.
He added that the global implications of this phenomenon could mean that 2024 will break 2016’s hottest year on record.
In May, the WMO predicted that at least one of the next five years will be warmer than 2016. That report, led by the U.K.’s Met Office with partners around the world, also said there is a 66 per cent likelihood that the annual average near-surface global temperature between 2023 and 2027 will temporarily be more than 1.5 C above pre-industrial levels for at least one year.
Taalas noted that the world has just had the eight warmest years on record, even though there was a cooling La Niña for the past three years. Earlier this year, B.C. climate experts weighed in on the likelihood of El Niño developing this year, saying it could mean a warmer-than-normal fall and winter for the province.
Rachel White, an assistant professor of atmospheric science at the University of B.C.’s department of earth, ocean and atmospheric sciences, said “chances are, average temperatures will be slightly hotter this year, particularly in the second half of the year” because of the El Niño-Southern Oscillation.
The El Niño-Southern Oscillation, or ENSO, is a phenomenon that can change atmospheric circulation, which can cause cooler or warmer weather. There are three states: El Niño, La Niña and neutral.
El Niño is a warming of the ocean surface in the central and eastern tropical Pacific. When the temperatures warm-up, there is typically more rain over the tropical Pacific Ocean.
