Temperatures

 

Significant temperature increases throughout Quebec are expected until the end of the century (Figure 1). It can be seen that for the next 30 years, the temperature increases are similar, regardless of the greenhouse gas emissions scenario. However, around the 2050s, global warming will slow if society succeeds in limiting its greenhouse gas emissions; otherwise, it will accelerate. There is clear urgency to act, both to reduce greenhouse gas emissions in order to stabilize the climate and to adapt to the inevitable changes. 

As with the observed trends, the climate models project differences depending on the region. There is more marked warming in northern Quebec than in the south of the province. 

 

Figure 1

Figure 1 : Change in average annual temperatures throughout Quebec from 1950 to 2100. Average temperatures observed (in green), modeled (in gray) and projected in the future based on moderate (in blue) and high (in red) greenhouse gas emissions scenarios. Taken from the Ouranos Climate Portraits.

With a high emissions scenario

In the north, the projections show average annual temperature increases of 3 to 5°C for 2050 and of 4 to 9°C for 2080.
In the south, they show average annual temperature increases of 2 to 4°C for 2050 and 4 to 7°C for 2080.

*Anticipated changes are relative to the historical reference period of 1981–2010.

Summer temperatures

In the summer, the increase in temperatures will result, in particular, in more frequent heat waves, especially towards the south of the province, which is consistent with various studies, including those of the Intergovernmental Panel on Climate Change (Figure 2). For example, in Outaouais, while the maximum regional temperature exceeded 30°C about 5 days per year during the last few decades, it could do so up to 20 days per year in 2050 and 45 days in 2080, which corresponds to nearly a month and a half a year. By way of comparison, towards the end of the century, the city of Gatineau could experience the intense heat currently observed in Denver, Colorado.   

Warmer summer temperatures also result in more growing degree days. Once again, the south of the province will experience the largest increases, with 660 more growing degree days by 2050, while the north could gain 250. 
 

Definition | Degree days

A degree day is the difference, in degrees Celsius, which separates the average daily temperature from a base value, determined according to the context, for example, 4˚C. If the value is equal to or less than 4˚C, the day has zero growing degree days.

Figure 2

Figure 2 : Average of the number of days with a maximum temperature above 30°C from 1981 to 2010 (left panel) and the median for the period 2071–2100 with a high greenhouse gas emissions scenario (panel at right). Taken from the Ouranos Climate Portraits.

Winter temperatures

Winter temperatures are also on the rise, more markedly in the north of the province, with increases reaching 10 to 15°C at the end of the century for a high greenhouse gas emissions scenario. These regions will also see the number of days with winter minimums below -25°C drop from 50 to 20 by 2050. Central Quebec will lose about 25 days of extreme cold, while in the south, the estimate is around ten days.

Freeze-thaw events will be less frequent on an annual basis all over Quebec. However, there are nuances depending on the season, with slight increases during the winter. 
 

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