On Sunday, the small mountain town of Lytton, British Columbia, became one of the hottest places in the world. Then, on Monday, Lytton got even hotter – 47.9C (118F) – hotter than it’s ever been in Las Vegas, 1,300 miles to the south. And by Tuesday, 49.6C (121F).
Lytton is at 50 deg N latitude – about the same as London. This part of the world should never get this hot. Seattle’s new all-time record of 108F, also set Monday, is hotter than it’s ever been in Miami. In Portland, the new record of 116F would beat the warmest day ever recorded in Houston by nearly 10 degrees.
This heat wave was a perfect storm long in the making. After centuries of fossil fuel burning and decades of warnings from scientists, it’s time to say it: we are in a climate emergency.
It’s the mountains of the Pacific coast that have had an essential and unique role in making this particular heat wave possible. Climate change is not just warming the surface of the planet, it’s warming Earth’s entire troposphere – the lowest layer of the atmosphere where all our weather occurs. That’s particularly true in mountainous areas, where temperatures are rising even faster than elsewhere. When snow and ice recede or even disappear from mountains, the bare soil beneath can warm unimpeded. A 2015 study found that mountainous areas above 2,000 meters (6,500ft) are warming about 75% faster than places at lower elevations.
Warmer mountains along with the mega-drought now plaguing western North America – the most widespread severe drought on record – contributed to a high pressure “heat dome” that has been self-reinforcing this week to create truly extreme conditions along the Pacific coast. Dry, descending air rushing down the mountain slopes offshore towards the ocean created a literal pressure cooker, sending temperatures soaring to never-before-seen values.
Downstream of Lytton, flood warnings are now in effect for the river valleys as sudden snow and ice melt has created a torrent of rushing water. For the time being, Canada’s glaciers are melting so fast they’re flooding out homes under clear skies.
The imagery we should remember from this heat wave isn’t swimming pools and fountains, it’s friends and neighbors sharing air conditioning amid a pandemic in a city that’s 40 degrees warmer than normal. It’s young people braving heat stroke to demand climate action from a president who promised it to them. It’s the anxiety of not knowing when or where the next heat wave will be, but knowing that it’s coming. It’s about surviving a society where decades of racial segregation means that redlined neighborhoods are 15 degrees hotter than others.
Eric Holthaus is a meteorologist, author of hugely hopeful The Future Earth, and founder of Currently, a weather service built for the climate emergency
Please click on: Heat Waves: The New Normal
