Record Breaking Heat

We are facing a miserable forecast as record-strong high pressure creates a "heat dome" in the Pacific Northwest of the U.S.

Heat waves like this are one of the clearest manifestations of human-caused global warming, with studies showing that climate change boosts the odds of their occurrence and heightens their severity. Some recent studies, in fact, have shown that certain extreme heat events could not have occurred without an added boost from human-caused warming.

Update (June 25):  The land surface temperature (not air temperature) reached 118 degrees Fahrenheit in parts of the Siberian arctic June 20.  Credit: European Union, Copernicus Sentinel-3A and -3B imagery

Update (June 28):  Several all-time record highs were recorded on June 27. (And this is just mainly in Oregon!)

Also, Robert Hunziker points to a report published in Geophysical Research Letters that finds the Earth's energy imbalance has approximately doubled from 2005 to 20019.

Update (June 30):  I'm hoping this is the worst of it.

The temperature at the Yakima Air Terminal weather station hit 113 on Tuesday afternoon, comfortably topping the all-time record of 110 degrees reached there on Aug. 10, 1971.

Also, Anne Mulkern explains why this is happening with help from Oregon state climatologist Larry O’Neill.

The high temperatures came as the result of a high-pressure system over Oregon and Washington. Climate change played a role in that system, said O’Neill.

One of the mechanisms for the formation of a high-pressure system is tropical cyclone activity in the western Pacific Ocean. Those are the West Coast equivalent of hurricanes. And like hurricanes, they are strengthened by warmer ocean temperatures.

Update (July 2):  Jeffrey St. Clair recounts this week's heat wave.

[T]he "heat dome" shouldn't have caught any of use by surprise. The new normal is yesterday's abnormal. The surprises and anomalies come and go, but only in one direction. The hotter they come, the hotter the records fall. It’s time to stop calling the PNW heat wave "unprecedented" and start calling it the precedent for a future that has already arrived.

Portland's high temperature [of 116F on Monday] was 40 degrees above normal, 4.5 standard deviations from the mean, making it the most severe heatwave ever recorded in North America, the kind of event only expected to happen every 400 years. But these kinds of wild fluctuations usually happen in fall and spring, almost never in summer. Portand's deviation from the norm would be like Dallas hitting 134F.

On Sunday afternoon, Lytton, British Columbia, broke the record for the hottest temperature ever recorded in Canada with a measurement of 46.6C (116F). Then it broke that record again on Monday. And again on Tuesday with a high of 49.6C (121F), shattering the old heat record set 84-years ago by 4.6C (8F)!

Update (July 4):  Actual high temperatures for the past two weeks. From June 26 through June 30, records were either tied or broken.

Update (July 8):  From a study published by World Weather Attribution:

[A]n event such as the Pacific Northwest 2021 heatwave is still rare or extremely rare in today’s climate, yet would be virtually impossible without human-caused climate change.

Looking into the future, in a world with 2°C of global warming (0.8°C warmer than today which at current emission levels would be reached as early as the 2040s), this event would have been another degree hotter. An event like this – currently estimated to occur only once every 1000 years, would occur roughly every 5 to 10 years.

Update (July 16):  A short video made from satellite images shows the loss of snow pack on Mt. Adams during the heat wave. Mt. Rainier lost 30 percent of its snow pack from June 26 to July 11.

Update (July 18):  Peter Reiners explains why "wet bulb" temperature matters more than record highs.

The closer wet bulb temperature gets to our body temperature, the less heat is lost. ... [Anything] higher than 88 °F (31 °C) make it impossible to do physical labor, and a wet bulb temperature of 95 °F (35 °C) kills healthy humans within a few hours.

The National Weather Service has a calculator.

Update (July 26):  In an interview with Zoya Teirstein, Daniel Swain discusses extreme weather events.

I'm less convinced that recent events tell us that things are moving faster than projections have suggested. But I am increasingly convinced that we've underestimated the impacts of some of the changes that were actually fairly well predicted.

Climate models aren't intended to capture the fine details of transient events. Weather forecasts turned out to be fairly accurate--a forecast of 113 vs the actual 114 for that record-breaking day.

[T]his just keeps coming back to this notion that a degree or two of global warming doesn't sound like a lot, but it is a tremendous shift in the system. But that's not intuitively obvious to really anyone except for folks who really understand the dynamics of these nonlinear Earth systems interactions.

Update (June 14, 2022):  This year, over 100 million people in the U.S. are facing record-breaking heat at the start of summer.

Update (August 1, 2022):  There's just no escaping--this year's record breaking week for Yakima:

I believe the 27th through the 30th were all new record highs. This week saw the first 100 degree day of the year.

Update (August 20, 2022):  Last month set the record for the highest nightly low temperature.

The average low temperature for the Lower 48 states in July was 63.6 degrees (17.6 Celsius), which beat the previous record set in 2011 by a few hundredths of a degree. ... July’s nighttime low was more than 3 degrees (1.7 Celsius) warmer than the 20th century average.

Update (August 27, 2022):  China has been enduring a two-month heat wave that Maximiliano Herrera calls the most severe recorded anywhere.

This combines the most extreme intensity with the most extreme length with an incredibly huge area all at the same time. There is nothing in world climatic history which is even minimally comparable.

Update (September 6, 2022):  California is suffering from record-breaking heat.