Understand | What the summers of the future will look like

With the smoke from the forest fires, the heat, but also the torrential rains, does the current season give a good idea of ​​what Quebec summers will look like as the planet warms up? Probably, if we rely on the most recent models. Science popularizer Angelica Alberti-Dufort offers four sources to see how our summers will change by 2100.

A report – What science finds and announces

Let’s start at the beginning: research and knowledge transfer specialist Angelica Alberti-Dufort suggests first taking a look at a document from the IPCC, the Intergovernmental Panel on Climate Change, the global benchmark for climatic changes. The 40-page “Summary for Policymakers” summarizes the most recent knowledge on the current state of the climate and the changes expected on a global scale, explains the one who has a background in geography . “The IPCC finds that the global temperature has increased by almost 1 ^ohC since pre-industrial times, she says. It may not seem like much, but in some places, like near the poles, it’s more. And in the summer, hot extremes – heat waves – increase this global average. »

The IPCC also observes longer episodes without rain. According to scientists, these two trends, warming and more frequent droughts, will worsen by the end of the century. But that’s not all. “Episodes of extreme precipitation could also be more severe, with more intense thunderstorms and storms,” adds the researcher. On dry soil, all that water will run off faster and cause more erosion. According to the IPCC, nothing indicates that Quebec will escape these phenomena…

Patterns – Global trend, local consequences

World trends are interesting, but they don’t reveal what will happen in your backyard. To find out, the Ouranos consortium, which brings together 450 Quebec researchers, experts and decision-makers, including Angelica Alberti-Dufort, has developed its recently updated Climate Portraits. They make it possible to visualize the evolution until 2100 of indices of extreme heat or precipitation, for example, for each of the regions of Quebec. Thanks to a map, it is possible to visualize the planned changes at any location.

In a scenario where greenhouse gas (GHG) emissions would continue to increase by the end of the century, the annual number of days when the mercury reaches 30 ^ohC would go from 13 to 58 in Bois-des-Filion, in the Lower Laurentians. In terms of precipitation, even if the summer total varied little in Lebel-sur-Quévillon, in Jamésie, it would be more concentrated in “water bursts”. A fairly widespread trend in Quebec, show the models. Consequence: the water content of the soil will decrease, the forest fire season will lengthen from 10 to 20 days, and the burned surfaces will double, recalls the chapter devoted to Quebec of the report. Canada in a Changing Climate. Angelica Alberti-Dufort is the lead author of this comprehensive chapter on the impacts of global warming.

A comic strip – Suffocating summers in the city

“The impacts of extreme heat, which is unfortunate, is that it will mainly affect vulnerable populations, launches Angelica Alberti-Dufort. And that’s going to happen a lot in urban settings. The effects of heat islands coupled with those of global warming will aggravate “thermal discomfort” in the city during the summer. The ABC of the climate, designed by Martin PM and published by Un point cinq, devotes a page to these heat islands. A beautiful “illustration” of the phenomenon, says the scientist, who recalls – like the comic strip – that the temperature can vary by 10 ^ohC from one district to another depending on the presence of plants. “Not for nothing does everyone seek shade when the time comes to park their car! “, she says.

The ABC of the climate, which explains a series of concepts associated with climate change, also offers a few boards in spoken version. Always in town, underlines M^me Alberti-Dufort, municipal stormwater management infrastructure will be undermined by episodes of extreme precipitation. “Sewer geysers, that’s the kind of thing that could really happen more often,” she observes. Nothing to reassure the dozens of households that were flooded by the downpour of September 13, 2022 in Montreal…

A report – What if the water runs out?

Weather and climate are two separate things. The first concerns the days and weeks to come, the second reflects the evolution of time over decades. Even in a warming climate, there can therefore be cooler summers. Nevertheless, although it is an exceptional season, the very hot and dry summer of 2021 in Canada gives an idea of ​​the problems resulting from climate change.

The show green week, from Radio-Canada, devoted a report to the effects of this unusual season on water management in the country. “We really feel the distress of people and the urgency to find solutions,” observes Angelica Alberti-Dufort. green week focuses mainly on what is happening in the West, very affected in 2021. But it also focuses on the water situation in Quebec, which is hardly more encouraging, despite the apparent abundance.

The report also touches on the question of usage conflicts between the United States and Canada, an aspect that concerns Quebec. After all, water from the St. Lawrence, the main source for Quebec’s water distribution networks, comes largely from the United States. “Years when the level of the river will be very low, it is not excluded that we will have supply problems”, warns the researcher.