SO, WHAT REALLY IS AN EL NIÑO?

'It's just an El Niño year, we've got nothing to worry about...'

… at least that’s what we’ve been hearing in the lift lines and in our DMs. So we’re here to set the record straight, and answer your burning questions on what El Niño’s, La Niña’s have to do with snowfall, climate change and fossil fuels.

Small changes in sea surface temperatures can lead to big changes in the atmosphere and the weather that we experience. During normal conditions in the tropical Pacific Ocean, trade winds blow west along the equator, taking warm water from South America towards Asia, and cold water rises up from the depths of the ocean to replace the warm water - called upwelling. El Niño and La Niña are two opposing patterns that break the normal sea temperature conditions which create changes in the atmospheric pressure and have global effects on weather, wildfires, ecosystems and more. 

What is an El Niño? 

El Niño-Southern Oscillation is a change in air pressure over the Pacific Ocean. Trade winds weaken and warm water pushes back east towards North and South America. This causes the pacific jet stream to move south and changes global weather patterns: Austral-Asia experiences droughts, parts of South America see increased rain, flooding and erosion. For us up in Canada we get dry and warm weather - not exactly the ideal ski season. 

What about La Niña events?

La Niña’s have the opposite effect. Trade winds are extra strong, pushing more warm water east, bringing more cold water to the surface and pushing the pacific jet stream north. In Canada we get heavy precipitation and cooler winter temperatures - think epic seasons.

Image Courtesy of NOAAclimate.gov

Well great! It’s just an El Niño year so next year’s La Niña will bring an even better ski season than ever… right? 

Not exactly. El Niño and La Niña events are naturally occuring, but they’re not consistent. Episodes of El Niño and La Niña last between 6-12 months and can occur every 2-7 years but not on a regular schedule. 

What’s the link between El Niño-Southern Oscillations and climate change?

Recent research shows that human-caused greenhouse gas emissions and global sea and air temperature rise are increasing the frequency and intensity of El Niño events. Over the last 50 years strong El Niño and La Niña events have occurred more often, and we can expect more intense and frequent El Niño’s and La Niña’s with more frequent swings between them. The number of extreme El Niño events could double over the next century because of climate change-induced surface warming of the Eastern Pacific Ocean.

Image Courtesy of BBC News

While climate change will increase the number and intensity of El Niño events, El Niño’s will also exacerbate the impacts of climate change, inducing record breaking spikes in temperature, and creating the conditions for more extreme and frequent droughts, floods, heatwaves, wildfires and storms. Current sea surface temperature extremes driven by El Niño have intensified by 10% compared to pre-1960 levels.

Climate change will also affect La Niña’s typically cooler temperatures. Record-breaking global temperatures, such as 2022’s La Niña year ranking as the fifth warmest year on record, can happen even during La Niña years, demonstrating the long-term warming trend driven by climate change. 

Beyond El Niño and La Niña events, climate change trends under normal atmospheric conditions are already impacting our ski seasons. New research out in Nature demonstrates that anthropogenic carbon emissions and human-caused warming has already caused declines in snowpack across the Northern Hemisphere over the past 40 years. 

The relationship between global average temperature rise and snow loss is not linear though, which explains why we’re experiencing a range of winters across Canada. In places where average winter temperatures stay below -8C, like Alberta and Quebec, there’s very little snow loss, but once temperatures rise past that threshold, snow loss accelerates rapidly. Remember, climate is the average weather, which vary geographically (think Alberta vs Ontario) and over time (differences year over year), so we’ll continue to see better and worse seasons as climate change accelerates but the trends are clear.

Winter national temperature departures and long-term trend, 1948-2023

Looking forward, research from our Science Alliance shows climate change will continue contributing to winter temperatures, shortened ski seasons, less natural snow and more reliance on snowmaking across Canada. We’re even starting to see places where snowmaking can’t keep up.

But, what is key about all this research is the difference between business as usual continuing with high carbon emissions and the future if we stop emissions and meet the Paris Agreement targets. While El Niño events will continue, if we can stop carbon emissions, we can limit global temperature rise and #KeepItDeep.

If you liked this article and want to help protect the future of snow, demand our Federal government #KeepItDeep and cap oil & gas emissions now, with no more delays. Use our email writing tool here to have your voice heard.