Saturday , September 18 2021

Heat waves are rising across Canada – and hot nights are also more dangerous

When it comes to climate change, there is one fairly well-understood extreme that will affect people for decades to come: heat.

Scientists know that climate change will increase the frequency or intensity of events such as hurricanes, droughts, floods and heat waves. But when it comes to heat waves in particular, this is already seen around the world with deadly consequences. According to a a recent study published in The Lancet, more than five million people die each year from temperature conditions, with 91 percent of these deaths related to heat.

While many of these deaths occur in tropical countries, heat waves are beginning to affect the more northern climate.

Med the heat wave that suffocated British Columbia in late June in the first week of July killed more than 800 people (of this writing) in the province. For comparison, according to the chief physician of BC Coroners Service, dr. Jatinder Baidwan, there were 232 deaths in the same period last year. The coroner’s office continues to investigate all deaths to determine exactly how many were related to the heat.

The man leaves a community center in Toronto during a heat wave earlier this month. Some places between heat waves open cooling centers for people who do not have access to air conditioning. (Michael Wilson / CBC)

Although we know that daytime temperatures are rising, in some regions – especially parts of Ontario and Quebec – nighttime temperatures are warming faster.

These warmer nights mean our bodies don’t have time to cool down. For example, for people with health problems such as heart disease or asthma, this can be very problematic and potentially fatal.

“Our bodies were not designed to withstand environmental heat beyond the 1930s,” Baidwan said. “If you think about what happens to an air conditioner? When you emphasize it, a lot of ice builds up on it and then it stops working. And in a way, it’s a great analogy to what happens to our bodies. With extreme heat, it’s just hard to do the usual homeostatic mechanisms and protocols that take place in our body. “

WATCH | How can we better prepare our homes and buildings for rising temperatures?

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The heat wave that hit the Pacific Northwest was very unusual – according to a report. a recent analysis by the World Weather Attribution group, a collection of scientists analyzing severe weather events. However, in parts of eastern Canada, including Ontario and Quebec, more frequent heat waves and tropical nights are defined as night temperatures of 20 C or higher.

For example, according to Climate Atlas of Canadathe number of tropical nights in Toronto averaged about 6.9 per year from 1976 to 2005. Climate change is projected to rise to 17.6 per year from 2021 to 2050, according to a scenario where carbon emissions are significantly reduced.

If current carbon emissions continue, the average number of tropical nights in Toronto is expected to reach 20.6 per year between 2021 and 2050. From 2051 to 2080, the average number will increase to 26.4 and 42.8, respectively, in two different emission scenarios.

In 2018, a heat wave swept Montreal from June 29 to July 5; daytime temperatures averaged about 34 ° C. Nighttime temperatures did not fall below 20 C. A total of 66 people died.

“In Canada, we are seeing an increase in hot extremes that is greater than average global warming,” said Nathan Gillet, a research associate from Canada for the Environment and Climate Change. “The average warming in Canada is about twice the average global warming. And the extreme heats are also rising at a similar rate. But not only the hottest, highest temperatures are rising, but also the lowest temperatures, the nighttime minimum.”

Widespread impacts on nature

Average temperatures in Canada have already warmed by 1.7 C and the country is warming at more than twice the speed of a planet.

Rising heat waves with higher-than-average day and night temperatures are also taxing animals and sensitive ecosystems and crops.

A study published in the journal Global Change Biology October last year found that night temperatures were rising across most of the world. In those areas where the night warming temperature was more than during the day, more clouds, more rainfall and more humidity. This can affect nocturnal animals, as well as animals that are active during the day, using colder night temperatures to recover from heat stress.

Dead fish swim in the Pembina River in Alberta. The fish are said to have died due to the heat wave across Alberto, which caused low oxygen levels in rivers and lakes earlier this month. (Stephanie Coombs / CBC)

“[The changes] increase the limits at which nocturnal species can operate. This can lead to shifts in scale that then disrupt ecosystems due to changing competition and changing predation / prey relationships and the like, ”said Daniel Cox, lead author of the study and research associate in the UK at the University of Exeter. durability.

A new set of measurements

Due to the changing climate, governments are finding that they need a new set of measurements for severe heat events.

In 2013, Australia added new colors to its heat maps as temperatures rose more than in the past.

Recently, on Tuesday, the British office of Met published its first orange warning of extreme heat, as temperatures in some parts of the country are expected to rise by the 1930s. Daytime temperatures in the 30s may not seem high compared to some parts of Canada, but it’s just what people are used to.

In another case, as governments try to adapt to global warming, a team from the Institut National de la recherche scientifique (INRS) in Quebec, along with the Institut National de santé publique du Québec (INSPQ), announced on Wednesday that a new threshold of a warning heat wave for the province should be introduced. Researchers said Quebec’s warm season starts earlier and ends later.

As the Earth continues to heat up, air conditioning seems a possible solution. The problem is that their operation requires energy, which also produces heat. And cities are creating “thermal islands” where heating is further enhanced by concrete structures and adding more stress to people living in hotter climates. Some cities, such as Toronto and Montreal, are trying to introduce greener building codes and models to address this.

“[Heat waves aren’t] something we think of in Canada as a major threat, but as the climate warms, we will see this more and more, “said Canadian Gillet for Environment and Climate Change.” Heat waves cause death and are dangerous. And yes, there is something… that we will see more and more here in Canada. “

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