There may be a reason for this strangely cold winter. You won’t like it.
First, some background: Human carbon dioxide releases have increased its air concentration from 280 parts per million (ppm) to the current level of 400 ppm. Let’s say it will rise to 500 ppm in another 40 or 50 years before leveling off. This would mean that we’ve already passed the halfway point in adding carbon to the air. Yet what are the effects? As you go about your life in the Hudson Valley, has it changed meaningfully? Or even a tiny bit?
In our region, the most thorough daily measurements are those found at the Mohonk Preserve’s Daniel Smiley Research Center. The Preserve’s Director of Research Emeritus Paul Huth – for decades in charge of this project, which includes observations of bird migration and tree growth – told me that compared to a century ago, our growing season is now about two weeks longer. Birds that used to migrate now hang around all winter. None of the effects are bad.
But the very first significant negative climate change consequences for our region may be showing up. Their genesis is the fact that high latitudes are warming much more than the rest of the planet. That’s why Arctic Ocean summer sea ice is vanishing, and Greenland glaciers are melting faster. Each year in Alaska I’ve seen the results of melting permafrost.
In a couple of recent journals, researchers are noting something strange and a bit ominous: The temperature difference between far northern latitudes like the Arctic and the rest of the planet – less extreme than it was just 20 years ago – is apparently affecting global wind patterns. The jet stream, which normally barrels along in more or less a straight line from west to east, is developing a wavier pattern. It’s also slowing down a bit. And once it develops a particular north/south wave, that wave tends to persist. This is where we come in.
The Great Lakes are now mostly frozen. No surprise: This will be at least the second-coldest February, if not the coldest, since the daily observations began at Mohonk more than a century ago.
The reason has to do with…yes, a weirdly persistent wavy jet stream pattern. The top part of the wave has been positioned much farther north than usual over the western states, letting extremely mild air persist there. That same looping jet then dives southward at around the longitude of the Rockies. Thus bitterly cold air from Siberia and northern Canada – the famous polar vortex – has a straight shot into our region. This pattern has persisted for more than a full month, which is very unusual. Happily, it cannot last too much longer, simply because Earth’s axis is now rapidly changing its tilt, so that far northern latitudes are becoming increasingly sunlit.
Now, it’s stupid to blame every weather anomaly on climate change. But our strange cold this winter is definitely due to that persistent wavy jet stream. And waviness has now materialized for the past five winters. Four were colder than normal. One of the winters, 2012/13, also had a wavy jet, but its configuration was positioned in a way that brought us warmer-than-normal temperatures that year. However, most experts think that the pattern we’ve seen this winter will be the more usual one. If so, cold winters in the Northeast may become the new normal.
This is not carved in stone, so let’s hope that this modeling is incorrect. If it’s true, it will be our region’s first solidly negative consequence from climate change.
Last winter, the Great Lakes froze sooner than had been observed since 1996. This winter the same thing is happening. Right now, 98 percent of Lake Erie is frozen. It’s always the first Great Lake to freeze because it’s shallowest, and typically gets an essentially solid surface by January 24. More than 90 percent of Lakes Huron and Superior are now frozen, too. Only Lakes Michigan and Ontario are under 85 percent solid.
This affects us. Buffalo’s lake-effect snowstorms depend on liquid water in Lake Erie, while storms in places like Syracuse and Watertown feed off the moisture from Ontario. Some of those snows often make it as far as Albany and even the Berkshires, Greens and yes, our Catskills. When those lakes get frozen, it puts a stop to that snow. That’s one of the few consolations in this very odd winter.
Need a break? Join me in Alaska for the amazing Northern Lights. Choose March 17 or March 24. Call (845) 901-7049 or visit https://bermanastronomytours.com.
Want to know more? To read Bob’s previous “Night Sky” columns, visit our Almanac Weekly website at HudsonValleyAlmanacWeekly.com.