Why British Columbia is especially vulnerable to the effects of a climate breakdown

There are a couple of key takeaways for British Columbians from the climate crisis.

Rising levels of water vapour in the atmosphere due to a warming Pacific Ocean are bringing more torrential downpours to the province. And that's having devastating economic implications.

The second key takeaway is that heat domes are far more deadly than extreme rainfall.

In the worst cases, atmospheric rivers are bringing extreme precipitation deeper into the mainland of B.C., in some cases changing the topography of the landscape.

An early sign of this occurred back in 2013 when a record amount of rainfall fell in the Kootenay-Columbia River region, cutting off highway access.

But that was far less severe than what occurred last November when intense rainfall caused the the Coldwater River to change its course through Merritt, which suffered historic flooding.

As a result of that storm, the Nicola River changed course as well, washing out large sections of Highway 8 between Spences Bridge and Merritt.

The Coquihalla Highway was also washed out in places.

The billions of dollars of damage caused by the November flooding, which also hit Abbotsford and Princeton, left a lasting impact not only on the economy, but on people's psyche. If it could happen once, could it happen again?

Unfortunately, the answer is probably "yes".

Here's why. Two 19th-century thermodynamics researchers, Rudolf Clausius and Benoît Paul Émile Clapeyron, discovered that for every 1° C increase in temperature, the atmosphere can hold seven percent more water.

As the planet warms, this is adding a powerful punch to the storms coming in off the Pacific Ocean, putting B.C. at the front end of the climate crisis.

As warming increases—and it will because of the "carbon lag" from current emissions—it will likely bring more and possibly even larger atmospheric rivers to the province.

But there's something else also occurring over the Pacific Ocean.

According to the U.S. National Oceanic and Atmospheric Administration, the warmer water temperatures in the western part of this body of water also contribute to heat waves.

On its website, the NOAA likens the ocean to a swimming pool when the heater is turned on. Using this analogy, temperatures increase faster in areas closer to the heater jets.

"If one thinks of the Pacific as a very large pool, the western Pacific’s temperatures have risen over the past few decades as compared to the eastern Pacific, creating a strong temperature gradient, or pressure differences that drive wind, across the entire ocean in winter," the NOAA states.

"In a process known as convection, the gradient causes more warm air, heated by the ocean surface, to rise over the western Pacific, and decreases convection over the central and eastern Pacific," it continues. "As prevailing winds move the hot air east, the northern shifts of the jet stream trap the air and move it toward land, where it sinks, resulting in heat waves."

Evidence suggests that those heat waves become more intense when the undulating atmospheric Rossby waves, which are associated with pressure systems and the jet streams, become "quasi-stationary" and far more amplified.

This was explained in a 2017 paper published in Scientific Reports.

"In summary, our analysis of both historical model simulations and observational surface temperature data, strongly suggests that anthropogenic warming is impacting the zonal mean temperature profile in a manner conducive to wave resonance and a consequent increase in persistent weather extremes in the boreal summer," wrote climate researchers Michael Mann, Stefan Rahmstorf, Kai Kornhuber, Byron A. Steinman, Sonya K. Miller, and Dim Coumou.

"Combined with other additional proposed mechanisms for climate change impacts on extreme weather, this adds to the weight of evidence for a human influence on the occurrence of devastating events such as the 2003 European heat wave, the 2010 Pakistan flood and Russian heat wave, the 2011 Texas heat wave and recent floods in Europe."

The paper was published before the 2021 heat dome that killed nearly 600 British Columbians. It offered further evidence that the climate is messing with the jet streams, which are narrow bands of wind in the upper atmosphere blowing from west to east.

They follow boundaries between hot and cold air.

"As the difference in temperature increases between the two locations the strength of the wind increases," the NOAA explains on its website.

But in summer, with a warming Arctic region, the difference in temperature diminishes, slowing down those jet streams. And that could be a factor is so many people dying last summer from extreme heat in B.C.

One of the most recent examples of extreme flooding occurred in South Africa, killing hundreds and leaving tens of thousands homeless, according to the Guardian.

Mann, the lead researcher in the 2017 paper in Scientific Reports, was recently on the BBC to discuss the role of the climate crisis in this event.

"At some point, it's really basic physics," Mann told the BBC. "A warmer atmosphere holds more moisture. So when you do get rainfall, you get more of it in shorter periods of time. That's what we're seeing here—unprecedented flooding. About two centimetres of rain fell per hour for a 24-hour period."