Goodbye ‘normal’: What climate change is doing to summer in Canada
So far, the summer of 2021 has seen a deadly heatwave, wildfires, flooding and extreme drought.
Canada’s all-time temperature record was broken, several times over, in the village of Lytton, B.C., before it burned to the ground.
It’s clear — there is nothing normal about this summer.
Climate change is part of it, and some hope the extreme conditions will help prompt action.
“We’ve seen this before … and everyone gets fired up to do something about the climate and climate change,” said Dan Tait of Kelowna, B.C.
“But then, as the next fall comes around, so many of us tend to forget about it … and we’re starting from zero.”
This week, Radio’s What On Earth explores how a warming world is changing what we consider to be ‘normal,’ and what we can do about it.
For meteorologists, the climatological “normal” for a location has a really specific definition, based on the past 30 years of weather.
The practice dates back to 1935, and a meeting in Warsaw of the International Meteorological Organization (which later became the World Meteorological Organization, a UN agency), historian Kris Harper, a professor at the University of Copenhagen, told What On Earth.
While some weather data in the U.S. was gathered by meteorologists and sent by telegraph, she said, most was logged by hand by volunteers and mailed in at the end of the month — a slow process that wasn’t meeting the growing demand for weather information.
The Warsaw gathering decided that that 30 years of data would be used to set “climatological standard normals,” starting with Jan. 1, 1901 to Dec. 31, 1930, and updated after that.
The practice is still in use today, with the U.S.government this spring releasing what are literally new “normals,” covering the years 1991-2020 — showing obvious warming.
Environment Canada is still working on updating its 1981-2010 normals, but the fingerprints of climate change are clear here too.
Normal is going to be an increasingly difficult concept for us to wrap our heads around.- Brett Soderholm, meteorologist
Summer temperatures rising on average 1.5 C from 1948-2016 and Environment Canada data show a significant increase in extremes with important health implications in many locations — including about six more hot nights (over 22 C) each summer in Windsor, Ont., and 15 more hot days (over 30 C) each summer in Penticton, B.C.
What does ‘normal’ mean now?
While those changes have been predicted as greenhouse gas emissions continue to rise, the deadly late-June heatwave is a clear example that climate change will also bring events we don’t see coming.
It was so extreme that when an international team of scientists analyzed the role of climate change in the heatwave, their statistical modelling at first told them the temperatures observed were “impossible,” said Geert Jan van Oldenbourgh of the World Weather Attribution Group.
Meteorologist Brett Soderholm was forecasting for the B.C. Wildfire Service in Prince George, and had to completely ignore the climate normals that are usually a “sanity check” for his forecasts — because the temperatures coming were 20 degrees above normal.
“Normal is going to be an increasingly difficult concept for us to wrap our heads around,” said Soderholm.
“Looking ahead to the future, I think we’re just going to be able to use normal as a reference point for how extreme we are from one side to the next.”