Temperatures last week hit 108.7 degrees in Paris, part of a days-long heat wave that toppled all-time record high temperatures in at least five European countries. At the same time, a blast of chilly temperatures descended over much of the Lower 48, bringing record low temperatures.
Austin set a record low July temperature of 58 degrees on the 25th. The autumnal air mass broke or tied record low temperatures three days in a row in Little Rock and Waco, Tex. Copper Basin, Idaho, plunged to 24 degrees.
Yet the heat grabbed all the headlines. This is not because reporters intentionally ignore record cold. It’s because the heat was far more exceptional. Climate change has made it this way, knocking the normal balance of heat and cold off kilter.
If the climate was stable, the intensity of pools of cold and warm air would match. Because of the way the jet stream works, when it’s warm in one place, it’s necessarily cool somewhere else, and vice versa.
Like a seesaw, when the jet stream rides over a bulging dome of hot air, it then plunges south downwind, forming a pool of cold.
Last week’s heat wave was a case in point. About the same time temperatures were baking western Europe, a lobe of Arctic air brought temperatures some 20 degrees below average to parts of Russia.
Along the blob of cold’s eastern periphery, Susuman dropped to 24.6 degrees, while Talon fell to 29.5. (And another shot of cold air is expected to revisit western Russia later this week. Moscow will struggle to reach 60 degrees until Friday, while Nizhny, about 250 miles to the east, will remain in the mid-50s. Their average this time of year is 73 degrees.)
But while these cold waves do exist, they in no way disprove climate change. In fact, they are supposed to happen — it’s physics. Dismissing climate change because it’s cold somewhere is akin to claiming hunger isn’t a major problem because you had a big breakfast this morning.
This apparent “balance” will always exist but will become increasingly skewed as heat-trapping gases build up in the atmosphere. Humans, through changing the climate, have shifted this distribution in the warm direction. The atmospheric playing field is no longer level.
In the past week, there have been 27 all-time record-high maximum temperatures set, and eight record-high minima. During the same time, not a single all-time record cold temperature has been set anywhere on the planet. Not a single station — out of 27,406 — saw an all-time low.
Let’s try the past 30 days. Two stations did set all-time lows! Does that disprove climate change? Nope — 133 stations set record-high temperatures.
Maybe it’s just been a warm month. After all, July could be a top contender for the warmest month on record. But we can look further in the rearview mirror to see if there’s a pattern here.
During the past year, there have been 516 all-time record highs compared with 130 all-time record lows. That’s nearly a 4 to 1 ratio.
If there were no external influences — like, for example, man-made climate change — we should see a pretty even 50/50 split. That’s not the case.
Worldwide, 48,562 daily heat records have been set this year. That’s not nearly as impressive as all-time records, but is still meaningful. Contrast that to 30,562 daily cold records and the trend holds. It’s also illustrative that, even if the ratios are closer on the day-to-day, there are disproportionately more high-end extreme heat events than top-tier extreme cold.
Year to date, that hasn’t been the case in the United States. There has been almost a dead tie, and in some cases, cold records are winning. Take the 94 all-time heat records set in the United States this year compared to the 111 all-time cold records, for instance. February, March and May were all below average in the United States.
But despite the seesawing of weather, long-term climate trends prevail. The National Climatic Data Center reports the United States is running 0.22 degrees above normal for the January through June 2019 period.
Moreover, we have to remember that, even if our thermometer reads a bit cool from time to time, the world is a lot bigger than our backyard. The United States occupies only 1.92 percent of the surface area on Earth. Even if we’re chilling, someone else may be baking.
So long as we continue to emit greenhouse gases, the warm departures from the norm will continue to win. It’s sort of like a pendulum. Half the time, the pendulum will be more to the left, and half the time it’ll swing to the right. But if you put that pendulum on a bus, suddenly that pendulum is making preferential progress in one direction.