What is El Niño and how does it affect Alberta’s weather?
In December, El Niño peaked as one of the five strongest on record. The effects of this were felt in Canada, with the country experiencing warmer-than-average winter temperatures. The current El Niño formed in June 2023, and though it is fading, the impacts are expected to continue through May.
David Phillips, a senior climatologist with Environment and Climate Change Canada, notes 2023 as the warmest year on record due to long-term climate change and the 2023-24 El Niño episode. He credits the winter warmth to a big El Niño combined with residual heat from last year in several bodies of water globally that was given up to the atmosphere, keeping the winter from cooling off.
WHAT IS EL NIÑO?
Typically occurring every two to seven years and lasting nine to 12 months, El Niño is a climate pattern associated with the 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, lasting for several months. The normal temperatures used as reference are averages calculated over 30 years.
Phillips recognizes fishermen in South America as the first to notice the changes of El Niño. The warming of the water negatively affected fish population in their region so they took note of temperature trends.
It is naturally occurring, but “its impacts are exacerbated by climate change,” said Claire Nullis from 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 may be warm temperatures, heavy rainfall, flooding and drought, depending on the region. These weather events may then create issues with agriculture and water supply.
The weather warms due to ocean temperatures. The weather above the ocean works to sustain itself, warming regions for weeks to months.
Heavy rainfall and drought are caused by western winds disrupting precipitation patterns. Southern U.S. states are more likely to experience rain and flooding, while northern states and Canada will see warmer temperatures and drought.
The weather impact of El Niño is long-term, “it gives the flavour or personality of weather coming up over several months,” said Phillips, on why there are still cold-snaps and unexpected weather events during an El Niño event.
El Niño is one of three phases of a recurring natural phenomenon called 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 major influence on climate 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 warmer global temperatures, but said, “the main driver of the increase is humaninduced climate change.”
Phillips mirrors this sentiment, saying, “one of the big factors that is driving what the winter is going to be, is climate change.” He comes to this conclusion by looking at a history of La Niña events and warming weather patterns during those years that should, scientifically, be cooler.
Historically, La Niña winters were colder. While there is no guarantee, you could bet on the fact that these years would be colder, said Phillips. From 1950 to 1987, over 12 La Niña’s, eight were colder and four were warmer. In the last 27 years, over 15 La Niña’s, more were warmer than colder.
“It’s almost as if climate change has trumped the effects of El Niño,” said Phillips. He credits last year’s warmth to El Niño and climate change moving in the same direction.
Phillips believes there is too much emphasis put on El Niño and La Niña, saying while it does raise the odds and allow for severe weather conditions, there are also other factors at work.
EFFECTS ON ALBERTA
Alberta’s water shortage and drought conditions may be an effect of the 2023-24 El Niño, though experts are saying it is likely a combination of the weather event and climate change.
Dr. Israel Dunmade, Professor of Environmental Science at Mount Royal University, believes the two are working together, causing damaging conditions in Alberta. “The depth of this warmth and the drought that we are seeing are aggravated by climate change,” he said.
To put in perspective the significance of the unseasonable warmth, Alberta’s winters have warmed up by nearly four degrees since 1948. In comparison, the world has warmed by 1.2 to 1.5 degrees. The province has been heating up, consistently, for 76 years.
The unseasonably warm and dry 2023-24 winter season brought on by El Niño exacerbated drought concerns and a water supply problem already prevalent in Alberta.
Dunmade said that while the upcoming expected transition from El Niño to La Niña should cause rainfall, it will not likely be enough to prevent a wildfire season similar to, if not worse than, 2023.