By Gaius
Publius, a professional writer living on the West Coast of the United
States and frequent contributor to DownWithTyranny, digby, Truthout, and Naked
Capitalism. Follow him on Twitter @Gaius_Publius, Tumblr and Facebook. Originally published at at Down With Tyranny. GP article archive here. Originally
published at DownWithTyranny
Temperatures over the Arctic
ocean are as much as 50 degrees F (30 Celsius) above normal. It’s above
freezing in places that are normally 20 below zero in degrees F. Arctic sea ice
collapse on the Atlantic side has allowed warm storms to penetrate the central
Arctic. This extreme heat is destabilizing the northern hemisphere’s
atmospheric circulation all the way up to the top of the stratosphere.
(Full-size image here.)
No, this is not a Season of
Merry and Bright post, despite the phrase “North Pole” in the headline. It’s a
climate post, to keep you up on the news.
Nick Visser writing at the Huffington Post:
North Pole Forecast To Be 50
Degrees Warmer Than Normal This Week
For the second year in a row,
the Arctic is way hotter than it’s supposed to be.
Temperatures in the Arctic are
predicted to soar nearly 50 degrees above normal on Thursday [December 22] in a
pre-Christmas heat wave that will bring the frozen tundra scarily close to the
melting point.
It’s the second year in a row
the North Pole ― now in perpetual darkness after saying goodbye to the sun
in late October ― has seen abnormally high temperatures around the Christmas
holiday. It’s also the second time this year. In November, temperatures in the
region skyrocketed 36 degrees above normal.
The weather forecast adds to a
string of climate change-related indicators setting off serious warning bells
in 2016. Polar sea ice is at record lows, and during last month’s heat wave, the
region lost 19,000 square miles of it in just five days. The National Snow and
Ice Data Center called the melt an “almost unprecedented occurrence.”
And it’s not just the North
Pole: “The World Meteorological Organization has said it expects 2016 likely will surpass last year as the hottest year in
recorded history.”
Changes in the Jet Stream
If you’re thinking, “Well, we
don’t live in the Arctic, so it doesn’t affect us … yet,” you’d be wrong. All
of these changes to atmospheric temperature in the Arctic are affecting global
air circulation, including the jet stream.
From a highly technical post
at Daily Kos by “FishOutOfWater,” a geochemist by profession (emphasis
mine):
The lack of sea ice has
dramatically affected the northern hemisphere’s atmospheric circulation for
months. The heat this fall has formed a warm dome over the Arctic ocean and
provided moisture for deep, early Siberian snow. A record deep Siberian snow
pack for October pushed south of normal developing a deep pool of cold air over
central Siberia.
The much larger than normal
temperature contrasts (gradients) across Central Eurasia have intensified
the polar jet stream across Asia and the north Pacific Ocean. This is a
predicted consequence of intense early snowfall in Siberia associated with warm
water entering the Arctic seas. This fall has had all time record minimum sea
ice extent in the seas north of Eurasia and this unprecedented weather pattern
is the atmospheric response to these warm waters so deep into the Arctic.
Intense atmospheric waves,
associated with intense storms have whipped across both the Pacific and
Atlantic. When intense storms approached the Arctic from both the Pacific and
Atlantic in late October the stratospheric polar vortex was pinched from both
sides, a 2 wave pattern, and split in two.
This stratospheric polar
vortex split is unprecedented for so early in the Arctic winter season as far
as I know. The stratospheric polar vortex is now unstable and may
undergo a major midwinter warming in the next ten days [posted in
mid-November]. It may be the earliest major midwinter warming ever seen.
More about the “polar vortex”
and the jet stream:
When the vortex of the arctic
is strong it is well defined, there is a single vortex and the arctic air is
well contained; when weaker, which it generally is, it will break into two or
more vortices; when very weak, the flow of arctic air becomes more disorganized
and masses of cold arctic air can push equatorward, bringing with it a
rapid and sharp temperature drop….
When the polar vortex is weak,
high pressure zones of the mid latitudes may push poleward, moving the polar
vortex, jet stream, and polar front equatorward. The jet stream is seen to
“buckle” and deviate south. This rapidly brings cold dry air into contact with
the warm, moist air of the mid latitudes, resulting in a rapid and dramatic
change of weather known as a “cold snap”.[3]
This is what happens when the
jet stream is destabilized and wanders (“meanders”) due to a weak Arctic polar
vortex.
Meanders of the northern hemisphere‘s jet stream developing (a, b) and finally detaching
a “drop” of cold air (c); orange: warmer masses of air; pink: jet stream (click
to enlarge; source)
It’s beyond doubt that changes in the jet stream are changing our weather. And a
“meandering jet stream” is more and more in our future, perhaps a permanent
addition. Welcome to the anteroom of the Palace of Climate Chaos.
Is it an emergency
yet? (Click the link for something you can do about it.)
No comments:
Post a Comment