What is El Niño and how does it affect Alberta?

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In December, El Niño peaked as one of the five strongest on record. The effects of this were felt in Canada, where the country experienced warmer than average winter temperatures. The current El Niño formed in June 2023 and, although it is fading, impacts are expected to continue into May.

David Phillips, senior climatologist at Environment and Climate Change Canada, notes that 2023 is the warmest year on record due to long-term climate change and the 2023/2024 El Niño event. He attributes the winter warmth to a large El Niño combined with residual heat from last year in various bodies of water around the world that was delivered to the atmosphere, preventing the winter from cooling.

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What is El Niño?

El Niño, which typically occurs every two to seven years and lasts nine to 12 months, is a weather pattern associated with warming of the ocean surface off the coast of South America.

El Niño is characterized by the water being warmer than normal by more than half a degree and lasting several months. The normal temperatures used as reference are averages calculated over 30 years.

Phillips credits South American fishermen as being the first to notice El Niño’s changes. Warming water negatively affected the fish population in their region, so they took note of temperature trends.

It occurs naturally, but “its impacts are exacerbated by climate change,” said Claire Nullis of the World Meteorological Organization.

El Niño affects seasonal climate averages and can cause extreme weather and climate events in some regions. Some effects of El Niño can be warm temperatures, heavy rain, floods and droughts, depending on the region. These weather events can create problems with agriculture and water supply.

The climate is warming due to the ocean temperature. The climate over the ocean works to sustain itself, warming regions for weeks or months.

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Heavy rains and droughts are caused by westerly winds that alter precipitation patterns. Southern U.S. states are more likely to experience rain and flooding, while northern states and Canada will experience warmer temperatures and drought.

The climate impact of El Niño is long-term, “it gives the flavor or character of the weather that’s coming for several months,” Phillips said, about why there are still cold snaps and unexpected weather events during an El Niño event.

El Niño is one of the three phases of a recurring natural phenomenon called the El Niño-Southern Oscillation (ENSO). ENSO is characterized by “fluctuating ocean temperatures in the equatorial Pacific, coupled with changes in the atmosphere, which have a significant influence on weather patterns in various parts of the world,” according to the World Meteorological Organization.

The other two phases are La Niña, the large-scale cooling of ocean temperatures in the same region as El Niño, and neutral, or La Nada.

El Niño and climate change

Nullis acknowledged that El Niño has been a factor in the rise in global temperatures, but said that “the main driver of the increase is human-induced climate change.”

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Phillips echoes this sentiment, saying that “one of the big factors driving what winter will be is climate change.” He comes to this conclusion by looking at the history of La Niña events and warming weather patterns during those years that, scientifically, should be colder.

Historically, La Niña winters were colder. While there’s no guarantee, you can bet these years will be colder, Phillips said. Between 1950 and 1987, in more than 12 La Niña episodes, eight were colder and four were warmer. In the last 27 years, in more than 15 La Niña events, there have been more warmer temperatures than colder ones.

“It’s almost as if climate change has surpassed the effects of El Niño,” Phillips said. He attributes last year’s heat to El Niño and climate change moving in the same direction.

Phillips believes there is too much emphasis placed on El Niño and La Niña, and says that while they increase the odds and allow for severe weather conditions, there are other factors at play as well.

Effects in Alberta

Alberta’s water shortages and drought conditions may be an effect of the 2023/2024 El Niño, although experts say it is likely a combination of the weather event and climate change. Dr. Israel Dunmade, professor of Environmental Sciences at Mount Royal University, believes the two are working together, causing harmful conditions in Alberta. “The depth of this heat and drought we are seeing is exacerbated by climate change,” he said.

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To put the importance of unseasonable heat into perspective, Alberta winters have warmed almost four degrees since 1948. By comparison, the world has warmed between 1.2 and 1.5 degrees. The province has been warming, steadily, for 76 years.

The unusually warm and dry 2023/2024 winter season brought on by El Niño exacerbated concerns about drought and a water supply issue already prevalent in Alberta.

Dunmade said that while the expected upcoming transition from El Niño to La Niña should bring rain, it likely won’t be enough to prevent a wildfire season similar to, if not worse than, 2023.

There are also concerns about how water shortages and drought will affect Alberta agriculture. Dunmade said the drought may be too significant and says “water management is very crucial to ensure we can get good food production.”

One of the reasons water shortages in Alberta are significant this year is because the province has experienced several dry growing seasons in a row. “What we’re seeing is a continuation of the same thing,” Phillips said, “we need the climate to change.”

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