More extreme rainfall linked to climate change: Study
The risk of flooding and extreme rain danger in Canada is likely here to stay.
In a study published recently by researchers at Environment and Climate Change Canada, climate change has made rainfall more severe in recent years, and has also made storms with extreme rainfall more frequent.
Already, the resulting flooding has destroyed homes and belongings, leading to billions in damage. And the study projects it will get worse.
“And as we continue to see warming, we will continue to see increases in the frequency and severity of extreme rainfall,” Megan Kirchmeier-Young, co-author of a paper published in the Proceedings of the National Academies of Sciences. “And heavy rainfall is one of the major factors in flash flooding, particularly in urban areas.”
Researchers combined computer models and observed data for the most specific look yet at how climate change affects the kind of damaging rainfalls that turn streets to rivers.
Holds more moisture
The idea stems from physics. Because warm air holds more moisture than cool air, an atmosphere heated by climate change should hold more water and dump larger amounts of it.
Both insurance and environmental experts say more must be done to counter the rising risk of flooding in this country.
Natalia Moudrak, director of climate resilience at the University of Waterloo Intact Centre on Climate Adaptation told CBC News catastrophic losses due to extreme weather events have risen sharply. In the early 1980s, they averaged less than $500 million a year.
But from 2009 onward, they exceeded a billion dollars every year except 2015.
The level of flooding is not the only factor affecting losses. Other factors such as property values, paving over natural areas that can absorb rainfall and other kinds of disasters also contribute. But, Moudrak said, “flooding is by far the No. 1 driver. Water damages are rising in Canada, and it’s the elephant in the room.”
One of the methods provincial governments have used to address the rising risk of flooding is by offering to buy out properties from homeowners living in high flood risk areas.
“Taxpayers are starting to see what’s going on here and they simply aren’t willing to continue paying to rebuild in high-risk flood areas, so the solution is you try to give people the option of leaving or relocating to a safer area,” said University of Waterloo School of Environment, Enterprise and Development associate professor Jason Thistlethwaite.
Thistlethwaite told CBC Radio that homeowners will be seeing more buyout programs in the future.
“These strategies are by far the best forms of risk mitigation because you take exposure of people and property to the water and you bring it to zero by moving them to a safer location,” the professor said.
However, not every homeowner is open to the idea of selling their property. To make matters worse, not every Canadian is aware that they are living in high-risk flood areas.
“We have asked Canadians this question and found that only six per cent were correctly able to identify that they were, in fact, living in a high-risk flood area,” said Thistlethwaite, who also mentioned that Canada does not have widely publicly available maps designed for homeowners. Current flood maps do exist, but are typically old and have been drawn for engineers, not homeowners.
The Essex Conservation Authority, for example, does have an interactive map where homeowners, municipalities and others can map their property to determine flood risk. However, at first glance, it is not simple to use.
Moreover, Thistlethwaite also suggested that insurance is another issue. Prior to 2015, insurance only covered basic flooding coming in through a stormwater system (sewer backup), but insurance companies later offered overland flood insurance, which covers damage caused by water coming from sources such as overflowing rivers.
Overland flood insurance
As helpful as overland flood insurance is, its availability and price can stop homeowners from purchasing it, Thistlethwaite said.
The Insurance Bureau of Canada (IBC) believes the government needs to take on a bigger role when it comes to flood risk mitigation.
“You may buy a home based on municipal information, thinking it’s low-risk, but then find out that your bank or insurer views it as high-risk, which obviously would make you unhappy,” IBC vice-president of federal affairs Craig Stewart told CBC Radio.
“So, it’s up to us, frankly, in the private sector, and with governments, to get our act together and start sharing information much more actively than we’re doing right now,” he said.
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