US-Canada heatwave 'virtually impossible' without climate change, researchers say

The deadly heatwave that brought triple-digit temperatures to western Canada and the US and that killed hundreds of people was “virtually impossible” without climate change, scientists said. According to BBC, a new analysis by an international team of 27 scientists said that the deadly heatwave was a one-in-a-1,000-year event. The temperature records were so extreme - 116 degrees Fahrenheit in Portland, Oregon, and 121 degrees Fahrenheit in Canada’s British Columbia - that researchers said it was difficult to quantify just how rare the heatwave was. 

Scientists warned that Earthlings can expect extreme events such as this to become more common as the world heats up due to climate change. The team, working under the umbrella of Oxford University-based World Weather Attribution, estimated that human-caused climate change increased the likelihood of such a heatwave by at least 150 times. Scientists worry that global heating, largely as a result of burning fossil fuels, is now driving up temperatures faster than models predict. 

It is worth noting that Canada’s previous national record for high temperature was 45C. However, the recent heat in the village of Lytton in British Columbia saw a figure of 49.6C recorded at the height of the event. All across the region, in the US states of Oregon and Washington and in the west of Canada, multiple cities reportedly hit new records far above 40C. These temperatures had deadly consequences for hundreds of people, with spikes in sudden deaths and big increases in hospital visits for heat-related illnesses. 

Two possibilities for extreme temperatures 

Now, scientists have said that the chances of heatwaves occurring without human-induced warming were virtually impossible. The researchers have urged adaptation measures that account for the rising risk of heatwaves, including action plans that incorporate early warning systems for high temperatures, as well as more ambitious targets to drastically reduce planet-warming greenhouse gas emissions. They also found that in a world with two degrees Celsius of warming, which could happen this century, such a heat event would occur about every five to 10 years. 

According to reports, scientists used computer simulations that compared a hypothetical world without greenhouse gas emissions to the existing world in order to assess the impact of climate change on weather events. They said that there are two possibilities for the extreme jump in peak temperatures seen in the region. The first is that it is just an extremely rare event, made worse by climate change, "the statistical equivalent of really bad luck". The other possibility is that the climate may have crossed a "threshold," that would make the kind of heatwaves witnessed recently much more likely.

(Image: AP/Unsplash)