El Niño is on our doorstep, but not all are created equal. So what does it mean for Canada?

A global weather phenomenon is coming.

The U.S. National Oceanic and Atmospheric Administration (NOAA) is forecasting an El Niño within the next few months, with a 90 per cent chance that it will carry on into the northern hemisphere winter.

El Niño is an unusual warming in the Pacific Ocean that, coupled with the atmosphere, can cause a rise in the global temperature. It can also affect weather patterns around the world.

"It's not 100 per cent. Nothing's 100 per cent," said Jon Gottschalck, chief of NOAA's Climate Prediction Center's climate operational prediction branch. "But right now, most of the observations and model forecasts are really painting that sort of picture that we'll go into an El Niño event as we enter the summer months or mid-summer period."

As well, the forecast El Niño could be mild, or it could be strong, such as the ones in 1997–1998 and 2015–2016, both of which recorded some of the highest global temperatures ever recorded.

While forecasting has certainly become better over the past few decades, the question always remains as to what some of the potential consequences could be for countries already dealing with a warming world, especially Canada, which has warmed at twice the global rate.

The problem is, not all El Niños are created equal. There are several different types, including a coastal El Niño, which occurs off the coast of Peru, or the dateline/Modoki El Niño, where the warming is found mainly in the central equatorial Pacific Ocean. And each of those bring different consequences to different regions of the world.

As the planet continues to warm due to increased CO2 in our atmosphere, the potential El Niño has climatologists and meteorologists on their heels, particularly as we have come out of a "triple-dip" La Niña. The three years of what is essentially the opposite of El Niño — where the region in the Pacific Ocean cools — still saw some of the warmest global temperatures on record.

And a potentially powerful or "super" El Niño could raise global temperatures further above the current 1.2 C of warming compared to pre-industrial times.

The whole El Niño/La Niña system — referred to as the El Niño-Southern Oscillation (ENSO) — has itself been changing. La Niñas have been warming, as have the El Niños and the in-between period of neutral observations.

WATCH | El Niño and La Niña explained:

"What's interesting about this, and I think it's so important to remember, is all of these events are getting warmer," said Simon Donner, climate scientist and professor at the University of British Columbia. "If we do end up with a strong El Niño event, if that same event happened in the 1800s, it simply wouldn't be as warm and the impacts wouldn't be as strong."

Just look at 2021, when during the "cool" La Niña, Western Canada saw devastating heat waves that contributed to the deaths of roughly 600 people. An all-time Canadian record-high temperature of 49.6 C was recorded in Lytton, B.C., which was practically wiped off the map during a particularly catastrophic wildfire season. 

Trying to determine the potential fallout in terms of extreme weather events in the ENSO cycle is especially difficult in the time of global warming.