On November 1, Environment and Climate Change Canada (ECCC) released its seasonal forecasts for Canada’s climate in the upcoming winter months. These forecasts predict above-average temperatures this winter across Canada. 

According to ECCC, an abnormally warm winter is especially likely in the maritime provinces and the Canadian Arctic, but high temperatures are also probable in highly populated parts of the country including Vancouver, Calgary, and Toronto. The prediction further states that average or below-average temperatures are not probable anywhere in Canada on any given day in December, January, or February.

Understanding climate forecasting

ECCC collects climate data at hundreds of weather stations across Canada — everything from temperature to rainfall to wind speeds. 

Climatologists can take years of historical data and plug it into a number of mathematical simulation algorithms called climate models to make predictions about future temperatures, precipitation, and other weather patterns. ECCC uses a number of different climate models to predict the weather patterns that are likely for each coming winter.

Climate forecasting is really just a game of predicting climate end states based on subtle environmental factors in beginning states, backed by historical data. The classic analogy to describe it would be predicting how long a car journey takes based on variables of departure time, traffic congestion, road closures, and so on. If someone makes the same journey every day for a month, they can guess their approximate arrival time based on these variables. They just can’t be certain. 

It’s the same principle with this climate prediction. ECCC predicts that the coming winter months will probably be warm based on data from recent years. They just can’t be certain yet.

Causes of a warm winter

This prediction is hardly surprising given the fact that overall global temperatures have increased from pre-industrial temperatures by an average of 1.1 degrees celsius according to the 2022 “Canada’s Changing Climate Report.” Though it is hard to predict what causes climate patterns for a given year, the recent trend in unseasonably warm and non-snowy winters — and the fact that 2023 is the second hottest year globally — is a result of these increased global temperatures caused by climate change.

But the 1.1-degrees-celsius figure is a worldwide statistic. Understanding the predictions in the 2023 seasonal forecast requires a bit more nuance. 

One main keyword that the media has been tossing around is “El Niño,” but it’s worth understanding what this actually means. Put simply, every two to seven years or so, the water temperatures in the central Pacific Ocean increase, causing significant climate variance across the world. For much of Canada, an “El Niño” event in the winter months means milder temperatures than a typical Canadian winter.

An El Niño event has been officially ongoing since the World Meteorological Organisation (WMO) formally declared it on July 4, 2023. The WMO reported on November 8 that the present El Niño event is likely to persist until April 2024, issuing a “widespread prediction of above-normal temperatures over almost all land areas.” El Niño will affect the climate of the entire world, and Canada is no exception.

Though El Niño events have been occurring for centuries and are a natural phenomenon in the Earth system, there is a growing body of research that suggests these events will become more frequent with heightened temperatures due to climate change.

Statistics of the Earth

Climate change is not about individual seasons and events — understanding the climate crisis means understanding frequencies, trends, and probabilities. Events like the forecasted warm Canadian winter or the 2023 El Niño are compelling symptoms of a warming planet, but it’s important that we don’t interpret these phenomena in a vacuum. 

Well-intentioned climate activists and concerned citizens might gesture to these events in isolation as manifestations of climate change, but such thinking is overly simplistic and potentially creates talking points for climate denialists. If an activist points to one warm winter as a sign of a changing climate, a denier might point to one cool summer as evidence to the contrary. This type of rhetoric is unrigorous.

In understanding global change, it is critical to understand the statistical nature of climatology. The 2023–2024 winter is likely to be unseasonably warm. And even though scientists cannot pin this fact on its own to the climate crisis, such warm winters are certainly going to become more common as the planet gets warmer and warmer.