The slowness of states to act to reduce greenhouse gas emissions risks causing warming that will easily exceed 4°C in southern Quebec well before the end of the century, warns the Group of Experts on Adaptation to Change (GEA) mandated by the Legault government.
The governments of Canada and Quebec have repeatedly repeated that they aim to respect the global objective of limiting warming to 1.5°C compared to the pre-industrial era, like the other signatory countries of the Agreement. from Paris, the reality is that the rise in temperatures could be almost twice as great over the coming decades.
Assuming that all States on the planet respect their current commitments to reduce greenhouse gas emissions, warming should exceed 2.8 ° C by 2100, or even 2070, underlined Tuesday Alain Webster, professor at the University of Sherbrooke, president of the Advisory Committee on Climate Change and co-president of the GEA.
“It is a bad scenario which does not lead us towards a stabilized climate,” he warned. Above all, such a scenario would imply an increase in temperatures of 4.3°C in southern Quebec and 6.1°C in the north.
This would mean that episodes of extreme heat in summer would be more intense and longer. A decade ago, there was an annual average of three days over 32°C. We could go to more than 20 days by 2040, then to almost 50 days before the end of the century, according to data from the National Institute of Public Health of Quebec.
According to the report Regional outlookfunded by the federal government and written primarily by experts from the Ouranos scientific consortium, “above certain thresholds, these temperatures can cause health problems such as heatstroke and dehydration, and are linked to rates of higher mortality.
The report also underlines that “the main vulnerable groups are the elderly and younger people who already have health problems, particularly mental health, as well as people living in disadvantaged environments”.
The most populated regions of the province would also face periods of sharp decline in water levels which risk “affecting the availability and quality” of drinking water in Quebec. Without forgetting an increased risk of flooding in spring, but also threats to the resilience of ecosystems and biodiversity.
Quebec would also be more vulnerable to forest fires, but also to freezing and thawing cycles which would damage important and costly infrastructure, such as roads. Rising water levels, coastal erosion and submersion would also hit maritime regions, causing significant consequences, particularly in Gaspésie and the Magdalen Islands.
” Risk management “
The prospect of warming of this order being plausible, there is an urgent need to plan adaptation measures, underlined Mr. Webster. This notably involves substantially increasing greening in urban areas in order to cope with heatwaves, but also the heavy rainfall to be expected.
GEA co-president Alain Bourque also considers it urgent to implement the recommendations made to the Quebec government, particularly with regard to infrastructure. “We have no choice but to be realistic about the different scenarios that may occur regarding global greenhouse gas emissions. So, if we build long-life infrastructure, we must take it into account in our risk management. »
“We are not convinced that we will succeed in limiting warming to 1.5°C, to say the least, but we must do everything to maintain the objectives set out in the Paris Agreement, because that in terms of adaptation, it will be easier to protect human health and natural ecosystems,” Alain Webster argued on Tuesday.
The disruption caused mainly by our dependence on fossil fuels has already reached 1.2°C and, over the last year, it has even temporarily exceeded 1.5°C, a threshold described as a “stark warning of the urgency of Actions to Limit Climate Change” by the Grantham Climate Change Research Institute at Imperial College London. According to the European Copernicus Observatory, the limit of 1.5°C could be out of reach in just over 10 years.
But this rise in global temperatures, which is two or three times greater in Canada, is nothing compared to what awaits us. The famous British daily The Guardian released a first-of-its-kind survey earlier in May in which it surveyed 380 authors and contributors to the Intergovernmental Panel on Climate Change (IPCC) who contributed to reports produced since 2018.
Nearly half of the IPCC collaborators questioned by The Guardian affirm that warming will exceed 3°C, and 58 scientists envisage warming which would be between 3.5°C (33 respondents) and a threshold exceeding 4°C, or even 4.5°C (21 respondents).