White Christmas: Another Endangered Species

Last week’s snow was thankfully kind to us. Though 6.3 official inches fell at the airport, it was not the foot that might have been and was long predicted, nor the ice storm that was also possible, nor the gale force winds that were expected. My staff at the Schuylkill Center breathed easier on Thursday morning when they arrived to shovel us out, as snow, ice, and wind can conspire to cripple our work, toppling trees and branches while causing power outages. So frankly, we’ll take an easier storm.

But temperatures returned to New Abnormal levels this week, as predictions call for a balmy 61 degrees on Christmas Eve. No White Christmas this year. In fact, the last recorded white Christmas occurred in 2009, and even then it didn’t actually snow on the day, but earlier in the week. The last time we recorded an inch or more of snowfall on the holiday was 2002, with only an inch and a half. The record for snowfall on Christmas is a foot, which fell way back in 1966, more than 50 years ago.

And I’m sure you remember that famed Christmas Eve only five years ago when the mercury topped out in the mid-70s, breaking December records as carolers sang in Hawaiian shirts and Bermuda shorts.
So last week’s snowfall may be an odd time to revisit climate change. But it is timely: remember, last week’s snowfall was the first major winter storm in almost 1,000 days, and is 21 times the total amount that fell all last winter. The Schuylkill Center’s facilities team did not have to plow our driveway once last year.

Remember, one weather event is neither proof nor disproof of climate change, so a snowfall in December does not mean all is fine and the climate isn’t broken. What one has to do is look at long-term trends. As the accompanying graph, created by temperature measurements collected by Climate Central in Princeton, shows, Philadelphia’s winter temperatures have warmed by almost five degrees since 1970. Five degrees may not seem like much at first glance, but the planet’s finely tuned climate instrument reacts strongly to even tenths of a degree changes in weather averages. In fact, winter has changed more markedly in Pennsylvania than the other three seasons.

Globally, NASA’s Goddard Institute for Space Studies calculates that 2020 has a more than 90 percent chance of becoming the hottest year on record, while NOAA, the National Oceanic and Atmospheric Administration, gives the year a 54 percent chance, possibly losing out by only a nose to 2016, as NOAA says the first 11 months of 2020 were a mere .02 degrees cooler than record-hot 2016.

Santa, gearing up for this week’s worldwide flight, is in trouble, as his North Pole is warming faster than the rest of the world. “One of 2020’s notable hotspots,” reported Scientific American last week, “has been Siberia… At one point the Siberian town of Verkhoyansk reported 100.4 degrees F. If this figure is verified by the World Meteorological Organization, it would be the first time recorded temperatures above the Arctic Circle have surpassed 100 degrees F.”

Imagine that: a measurement of 100 degrees in the Arctic Circle. Santa is quaking in his boots as the ice caps melt below his feet.

According to NASA, the Earth’s average temperature in November was 56.95 degrees Fahrenheit, 1.75 degrees above the 20th-century norm. Again, these small changes matter.

No matter where 2020 ends up in the standings, it will be warm enough to knock 1998 out of NOAA’s top 10. When that happens, all of the 10 warmest years in their records will have occurred in only the 15 years since 2005 — and the top seven will have occurred since 2014. The statistical odds that this is a random occurrence are slim to none, and each year is now as hot or hotter than the year before.

A 2017 analysis in Bulletin of the American Meteorological Society offered that between the late 19th century and 1980, new records for the hottest year would happen about every eight to 11 years, a reasonable rate that makes sense. Since 1981, however, they have been occurring about every three to four years. New records are now the norm.

“So if 2020 takes the top slot,” concluded the normally staid Scientific American, “it will not be entirely unexpected — and will be yet another stark example of how far the Earth’s climate has deviated from its natural course.” As a Goddard scientist told the magazine, “I work for NASA, but it’s not rocket science.”

May all your days be merry and bright nonetheless, though no, all your Christmases will not be white. Yet another casualty of climate change.

—By Mike Weilbacher, Executive Director

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