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Sea level rise ‘locked in,’ flooding possible in Richmond, says expert

The U.N.'s Intergovernmental Panel on Climate Change released its latest report this week
Richmond north dike
The new IPCC climate change report says sea levels are likely to rise by about half a metre by 2100 and coastal cities are at risk of extreme rainfall events and flooding, all of which are risks faced by Richmond according to SFU's John Clague. Pictured: Richmond's north dike.

Changes to the ocean due to climate change are “irreversible for centuries to millennia,” according to a major report released earlier this week by the U.N’s climate panel.

In its opening lines, the latest report from the Intergovernmental Panel on Climate Change (IPCC) says it is "unequivocal" that humans are to blame for climate change, and offered five possible futures the world could face depending on how much carbon emissions are cut.

In three scenarios, the world will also likely exceed 2 degrees Celsius, with far worse heat waves, droughts and flood-inducing downpours unless there are deep emission cuts.

But even if emissions are drastically cut and global warming halted at 1.5 degrees Celsius – which the world is expected to hit in the 2030s in each of the five scenarios – sea levels will still likely rise by around half a metre by 2100, and two to three metres over the next 2,000 years.

That “knock on” effect of climate change is something that will be witnessed in Richmond and Metro Vancouver, said John Clague, a Simon Fraser University professor emeritus in the Department of Earth Science.

“We’re pretty well locked in, in the Metro Vancouver area, to at least a half a metre of sea level rise by the end of the century – so over the next 80 years or so – (or) maybe a metre,” he said.

And while far less likely, scientists couldn’t rule out an even larger rise over the next several decades, as they don’t how the “elephants in the corner are going to behave,” he added, referring to the Greenland and Antarctic ice sheets.

“There are signs that they’re under stress, particularly the Greenland ice sheet, that it’s contributing more meltwater to the oceans than it did in the past.”

Because of this “deep uncertainty in ice sheet processes,” a global mean sea level rise approaching two metres by 2100 and five metres by 2150 if emissions continue at a very high level, “cannot be ruled out,” the IPCC report reads.

“That makes a big difference for Richmond,” Clague said.

He pointed out that Richmond faces the threat of both Fraser River flooding as well as sea level rise – and the two are linked because the lower portion of the Fraser River will rise along with sea levels.

The city is currently upgrading its dike system, planning for a one metre sea level rise by the end of the century – and recently accelerated the implementation period of its dike upgrade program from 75 to 50 years. 

But Clague said the city should be looking even further ahead than the end of this century.

“The point I always make is, this situation doesn’t end in the year 2100. You have to look beyond that,” he said. “For an individual citizen, you might not worry about that at all, but for the community, for the stability of Richmond as a city, you have to look beyond that.”

The end of the century also isn’t that far off – there are children being born today who will be alive in 2100, Clague noted.

“I think in the past we thought this was a problem that was going to impact future generations. Well, it's happening now, and children born now, and their children, are going to be dealing with this problem if we don't deal with it.”

A city staff report on the accelerated diking plan notes that the city regularly reviews and updates its plans and strategies “to accommodate changes to sea level projections.”

But a rising sea isn’t the only concern.

The IPCC report said that, even at 1.5 degrees Celsius global warming, heavy rains and flooding are projected to become more intense and frequent, including in many regions of North America.

Those risks will become even greater if the world hits 2 degrees Celsius and above.

“In coastal cities, the combination of more frequent extreme sea level events (due to sea level rise and storm surge) and extreme rainfall/riverflow events will make flooding more probable,” the report reads.

Clague said those risks also need to be taken into account by the city, noting that flooding can also have huge economic impacts.

“Maybe engineers in Richmond have thought through that, but they should be upgrading the storm sewer system to handle potentially stronger storms than historically we’ve experienced,” he said, adding it’s also something the region should be looking at, and would need to start work on early.

“The tendency of engineers and governments is to look at the historic record and build systems like storm sewers to deal with what has happened historically. And that doesn’t work if…the climate is changing on you.”

While the city’s flood protection strategy was updated in 2019, the city said it recognizes that climate change and sea level rise “is an evolving science and anticipate that updates to the (strategy) will be required every few years to account for new information as it becomes available.”

The city also said it has, for example, capital projects to increase capacity of drainage pump stations and the drainage network, as well as regular inspection and maintenance of drainage infrastructure, technical analysis and modelling, and required flood construction levels for new development to manage flood risks from rainfall.

Another strategy, said Clague, is to have “energy buffers” offshore to reduce the amount of energy storms have when they drive water onshore, although he said he isn’t sure this would work in Richmond given its important marsh habitat.

Nonetheless, considering “soft engineering” or green solutions is important, rather than relying, for example, on dikes to protect the city, he said.

But the latest IPCC report does offer some hope, said Clague.

“Now that scientists are saying there’s no question about it, (climate change is) 100 per cent something that humans have caused, well, the flip side of that coin is, humans can solve that problem too,” he said.

“It kind of offers some hope that we’ll more seriously deal with this issue than we have in the past.”

—With files from The Canadian Press