Pacific Northwest heatwave virtually impossible without climate change

The last week of June saw shocking temperatures in Oregon, Washington state, and British Columbia. Differentiating a forecast in Canada from a forecast in Phoenix is usually a breeze, but not in June. All-time high-temperature records—not just daily records—were smashed across the region. Portland International Airport broke its all-time record of 41.7°C (107°F) by a whopping 5°C (9°F). The small town of Lytton set a new record high for the entire country of Canada at 49.6°C (121.3°F) on June 29. In the days that followed, most of the town burned in a wildfire…

As with other extreme weather events, the World Weather Attribution team has generated a rapid analysis of this heat wave in the context of climate change…The goal is to fit a mathematical relationship that tells you how unusual an event was—it can produce figures like 1-in-10 or 1-in-50 odds in any given year, for example. But with events this extreme, the statistics are often challenging, as this heat wave went far beyond anything in the instrumental record. As near as they could estimate, the researchers put this heat wave at a 1-in-1,000 probability—the kind of thing that ought to happen roughly once in a thousand years.

Comparing this to the world before human-caused climate change requires adding in model simulations. As usual, the team compared historical temperatures in the area to a large database of models, tossing the simulations that fit the historical trend poorly. Statistics from simulations of climate in the late 1800s can then be combined with the historical data to see how rare this event would have been in the past.

Remember, it’s taken our dumbass species two centuries to screw things up this bad. Just because quantitative events have accumulated sufficiently to produce qualitative change…the disasters we’re sliding into…doesn’t mean they were caused by short-term phenomena. Nor will there be much of a chance for short-term solutions.