Yesterday, out here in California where the ongoing drought weather has us frighteningly warm and dry, I listened to the car radio news on the wandering Polar Vortex that got the Midwest and Atlantic seaboard shivering in temperatures too low to fathom. I believe it was NPR but am not sure and can't find anything like that news snippet at its site. But the reporter and an expert he interviewed got into why this big slug of deadly cryosphere air slipped its North Pole moorings, marauded across Canada, and swept through the eastern US.
The expert said an idea gaining traction (which many tracker readers already have heard) is that the loss of summer sea ice up there has decreased the temperature contrast between the Arctic and us. This in turn could weaken the ring of jet stream winds that normally encircle the pole just south of the Arctic Circle. They have always made the occasional excursion south to cross over the US during winter. But the meandering has become more common and extreme. Apparently the extra wobble has plausible ways to continue even when winter reskins the Arctic Ocean in ice. So it could be that this lazy "wavy" Arctic jet stream is escorting greater gouts of cold air out of the high Arctic much farther south and more often than was once usual. He told the audience furthermore that while this hypothesis is still pretty wobby itself, owhere near a demonstrated theory, it is scientifically plausible. It allows experts to responsibly say that the myriad, extra frozen tushies in Minnesota and lots of other places are consistent with and maybe a direct result of global warming. Which, as we all know, is the sort of declaration that already has invited howls of crackpotted derision from Fox News, Mr. Limbaugh, Marc Morano, and perhaps Lord Monckton (is he still around?) et al.
But, metaphors be with us dear stylebook, how are reporters evoking this general idea in plain English? The "wavy jet stream" is obscure and weak. It will leave many members of the public unable to picture the scene. I thought a simpler image is needed. Maybe say that global warming left the barn door open and the north wind has bolted for the tropics and, GW or nay, in the winter it is still re-e-e-eally cold up there. Or that their hobbles have gotten too loose. The wall is broken. Santa's fence is down. I have no idea, really.
But here are some that are making the rounds with metaphors or other key phrases batting lead off:
- "Breached its Meteorological Fence" — Christian Science Monitor – Pete Spotts: How frigid 'polar vortex' could be result of global warming ; Spotts also gets fast into the "warm-Arctic, cold-continenteffct." Its irony that the Arctic is warming up really fast, yet remains very very cold, hence global warming means more like global air mixing twixt pole and mid-latitudes. It episodically warms the far north while chilling southern regions and the long term average slowly climbs.
- "Whatever you call it, get used to it" — Bloomberg/Business Week – Eric Roston: Why Is It So Cold? The Polar Vortex, Explained ; His lede is fine, noting that PV has taken the lead in the 2014 buzzword race, and his second graf is a pullquote Donald Trump dumb tweet. The Meat is a straightforward summary of teh basic meteorology. A slight flaw is the suggestion here (and in other stories) that there is but two jetstreams, the polar ones (Arctic and Antarctic). There also are subtropical jet streams. And jets streams sometimes split into multiple routes. No biggie.
- NPR – Mark Memmott: What Is The Polar Vortex And Why Is It Doing This To Us? ; A blog collection of explanation snips from NPR and other sources. See also at NPR David Greene's interview with Climate Central's Andrew Freedman: Polar Vortex blamed For Dangerously Cold Weather ;
- "When the winds weaken, the vortex can begin to wobble like a drunk on his fourth martini … in this case, nearly the entire polar vortex has tumble southward" Time Magazine – Bryan Walsh: Climate Change Might Just Be Driving the Historic Cold Snap / …it could be that melting Arctic ice is making sudden cold snaps more likely – not less. Walsh leads with acknowledgment that skeptics are out in force, and blaming this cold on global warming might be a tough sell. And he notes that just a few years ago many climate modelers expected the Arctic jet stream to contract to the north. 'Tis "Global Weirding," he writes.
- "When things are normal and the polar vortex is strong, the refrigerator door is tightly sealed and the cold air stays inside" Chicago Tribune – Scott Kleinberg: Polar vortex, polar pig and other weird ways to describe this weather ; Kelinberg, says here, is the social media editor. But he does do a reasonable job on the topic and shares what some in the Windy City are calling this weather in the twitterverse: #chiberia.
- " a weaker polar vortex moving around the Arctic like a slowing spinning top, eventually falling over and blowing open the door to the Arctic freezer" The Guardian Environment Network (UK) Andrew Freedman: US polar vortex may be example of global warming ; Yes, Freedman is with Climate Central as noted above. Smartly noted here is an example of the relative warmth in many Arctic places lately – Prudhoe Bay hit 39 F early last month, the highest December temp seen there in about 45 years.
*UPDATE, or Dept. of Oh, Never Mind...
- New Scientist – Catherine Brahic, Aviva Hope Rutkin: US freeze is nothing to do with a 'polar vortex' ; Attributing this maverick view to the UK's Met Office, this brief piece argues that as the cold air is a lower-atmospheric or tropospheric blob and the polar vortex is by definition a stratospheric cyclonic flow, this is not the whole vortex that has headed south. Rather, a weak jet stream led the tropospheric Arctic cold pool to the US. Hmm. Seems a bit like a distinction without a difference, as the vortex is also defined as normally bounded by the jet stream, itself also primarily a stratosphere denizen.
Grist for the New Scientist's Mill: Met Office News Blog: What is causing the extreme cold over North America? This puts it rather more obliquely than New Scientist's bald declaration that this Arctic visitation "is nothing to do with a polar vortex." It does say US usage – which may be a reference mainly to the news media rendition of meteorology – is a bit different from the traditional one within the academy. Doodling around finds some old grist for the new news: A NASA press release from 2001 provides how the whole polar vortex breakout and jet stream weakening story made a public debut. It carried word of work at the University of Illinois that linked weak jet streams with break outs of cold, surface arctic air, including a direct if qualified interpretation that "the strength of the stratospheric polar vortex influences circulation in the troposphere."
Dept. of Zero Sum Air Supply:
An opportunity missed, so far as I can see, is this multipart question on zonal atmospheric mixing that might have been put to a PhD-type climate modeler or atmospheric physicist: "There presumably is no air-making machine in Santa's workshop. So when that brutally cold hunk of atmosphere leaves the dark winter north pole for some southern quadrant, does not an equal mass of air move up from the south behind it? How warm is that air? Does it add measurably to the Arctic's warming from open water that absorbs sunlight during the rest of the year? And when the Arctic blob finishes its trek south and returns, is it significantly warmed up?"
Dept. of Oh, Why Not:
- "If they're gonna tell us the polar vortex is responsible for this cold, that means record cold is also happening in the North Pole, which means there isn't any ice melting, and we know about the global warming expedition that went down to the South Pole, Antarctica, to prove that the ice is melting, and they got stuck, and then the rescuers got stuck, and then the people rescuing the rescuers got stuck, but never mind that." Excellence in Broadcasting – Rush Limbaugh: Left Creates "Polar Vortex" to Make You Think Winter is Caused by Global Warming ;