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Big
Arctic Warm-Up To Drive Freak Thanksgiving Snowstorm For US East
Coast
24
November, 2014
If
current trends continue, the eastern half of the US is in for one
extraordinary winter.
This
week’s extreme weather prelude brought a major warm snap that set
off rainfall, sent temperatures surging to 62 degrees in Buffalo and
pushed rivers in the area above flood stage. An odd northward hot air
surge ahead of the next blow. One that will be fueled by a similar,
out of the ordinary, Arctic heat-up that is predicted to fling a
freakish Thanksgiving snowstorm at the US East Coast on Wednesday.
(Maximum snowfall potentials for the predicted Thanksgiving Snowstorm as provided by the National Weather Service.)
A
storm that
may dump more than a foot of snow along a swath from Virginia to
Maineand set off blizzard-like conditions as a low pressure
rapidly intensifies in a raging storm track torching away off the New
England Coast.
Such
major predicted and potential snowfall amounts are more reminiscent
of a significant January event than what is typically seen for a
Thanksgiving period which usually features cold placidity. But this
Thanksgiving is predicted to be anything but placid as coastal gales
and record-challenging snowfalls are likely to sock holidayers in and
generate travel snarls throughout the Mid Atlantic and Northeast.
.
(Planetary wave pattern over Eastern US with intensified storm track in association with predicted strong winter storm for Thanksgiving in the Wednesday GFS model run. Image source: Climate Reanalyzer.)
The
spurs to this most recent Arctic invasion are two high amplitude Jet
Stream Waves — one over Alaska and one near Svalbard. Together,
these upper level flows are pulling yet more warm air into an already
warmer than normal Arctic. These invasions coincide with yet another
form of upper level warming — Sudden Stratosphere Warming (SSW). A
kind of warm air catapult up from the troposphere and into the Arctic
from over the Asian Continent.
A
combined set of conditions that is generating a baked atmospheric
cake set of warming for the Arctic and driving the southern edge of
the polar vortex southward over the Eastern US.
Overall,
Arctic heat anomalies are expected to spike as high as 3.5 C above
the already hotter than normal 1979 to 2000 average by the wee hours
of Sunday morning this week. A very strong warm departure for
November even in the current age of human-driven climate change and
polar heat amplification.
(Very strong early season polar warming and amplification during late November shoves cold air out over North America and Eastern Asia in the GFS model run. Note that average temperatures in this measure are based on the already warmer than normal 1979-2000 period. Image source: Climate Reanalyzer.)
Last
year, similar events drove cold air invasions through the Eastern
half of the US and greatly intensified the North Atlantic storm
track. As a result, the UK experienced its stormiest winter on
record. This year, warm waters in the equatorial Pacific and off the
US East Coast may well keep the storm track oriented along the Gulf
Stream. This would result in much stronger events for the Eastern US
and potentially quite powerful Nor’easter type coastal storms
should the current pattern persist.
Links:
Buffalo’s
Climate Change Driven Mega Snow-Food
How
melting Arctic ice is driving harsh winters
by
Nick Breeze
22
November, 2014
The
very least 'global warming' could do for us is to give us warmer
winters, right? Wrong, writes Nick Breeze, who met climate scientist
and meteorologist Jennifer Francis in his attempt to understand the
complex interactions of jet stream, polar vortex, the melting Arctic,
and the extreme snowfall that's hitting the northeast US right now.
"Historic"
snowfalls have the US northeast this week, with Buffalo, New York
under an astonishing 2.4m (8ft) of snow - enough to cause some roofs
to cave in under the pressure.
It's
just the latest chapter in 2014 unprecedented range of weather
extremes - from persistent storms that battered, and flooded much of
the UK at the beginning of the year, before going on to record the
hottest October since records began.
And
in the US, extremes have ranged from California's record drought, to
the early snows now under way in the northeast - and let's not forget
the 'polar vortex' that hit much of the US in January, bringing
Arctic conditions as far south as Texas and Florida, causing flights
to be cancelled in Chicago as aviation fuel froze in the -38.3C
(-37F) temperatures.
Scientists
now have evidence that these persistent extreme weather patterns are
increasing in their frequency, due to the rapid heating up of the
Arctic that is changing the behaviour of the jet stream, and in turn,
the polar vortex.
 |
| Screenshot from Youtube video further below |
The
'vast river of wind' that makes our weather
"The
jet stream in turn creates most of the weather that we feel all
around the northern hemisphere and the middle latitudes, so anything
that affects this jet stream is going to affect weather patterns. So
as the Arctic warms up much faster than the areas farther south,
we're seeing this temperature difference between these two regions
get smaller."
The
result of that, she explains, is that the atmospheric forces driving
the jet stream's circular motion are getting smaller - and that means
the winds themselves in the jet stream are getting weaker, and moving
more slowly.
"When
that happens, the jet stream tends to take a wavier path as it
travels around the northern hemisphere and those waves are actually
what create the stormy patterns and the nice weather patterns. As
those waves get larger because of this weakening of those winds of
the jet stream, they tend to move more slowly from west to east."
"That
means it feels like the weather patterns are sticking around longer,
because those patterns are moving much more slowly and this then
makes it more likely to have the kind of extreme events that are
related to persistent weather patterns."
Are
critical findings influencing policy?
These
changes in climate have huge implications. As Dr Francis points out,
there are "people
who worry about whether there is enough fresh water to supply cities,
whether there is enough snowpack on mountains to supply reservoirs,
and for agriculture ..."
"Drought
and agriculture is a big problem. Storminess in certain areas is
another big problem. Yes, it has a huge impact for a whole range of
issues that affect the way we live."
It's
no wonder then that Dr Francis and her colleagues have attracted the
attention of President Obama's chief science advisor, Dr John
Holdren.
Dr
Holdren has been reporting directly to the President on the real time
effects of climate change and is keen to understand what this new
research tells us about the future impact of changes to the jet
stream.
Asked
about this sudden interest in her work from the US Presidency,
Francis muses thoughtfully."Yes,
we've had a lot of interest from policy makers",
she acknowledges.
"I
think we're starting to make a lot of progress now in getting
policymakers to understand that this is a big problem they have to
face ... I think decision makers and the policymakers at the local
level get it much better because they're already seeing effects on
their local areas.
"Sea
level rise is an obvious one. They're already seeing changes in
drought and agricultural problems and dealing with fresh water
issues. It is really at the local level that we're having more
success."
New
research supports the case that Arctic sea ice loss is driving
climate changes
So
to understand the changes in the jet stream it's important to
research how the vast atmospheric river of weather above our heads is
connected to other climate mechanisms.
"It
appears that over the north Atlantic, and towards Asia, there's a
mechanism that appears to be quite robust, and several groups have
found this mechanism using completely different analysis techniques",
says Francis referring to new
research by colleagues at the University of Alaska that
has emerged in the last couple of months.
"So
what we're finding is that there's an area, north of Scandinavia in
the Arctic, where the ice has been disappearing particularly rapidly.
When that ice disappears ... there is unfrozen ocean underneath, and
that ocean absorbs a lot more energy from the sun through the
summertime. So it becomes very warm there."
"Then
as the fall comes around, all that heat that's been absorbed all
summer long, where the ice has retreated, is put
back in the atmosphere and
that creates a big bubble of hot air ... over that region where the
ice was lost."
And
in turn, that goes on to disrupt the circumpolar winds whose
behaviour determines much the weather across the northern hemisphere.
The
gigantic bubble of warm air "tends
to create a northward bulge in the jet stream",
and in turn, "that
creates a surface high pressure area that circulates in the clockwise
direction. That sucks cold air down from the Arctic over northern
Eurasia, and that creates a southward dip in the jet stream."
The
bulging jet stream disrupts the polar vortex
"So
what we're getting is this big northward bulge up over Scandinavia
and a southward dip over Asia ... creating, first the tendency for a
larger wave in the jet stream, which tends to move more slowly, but
also we're seeing this mechanism that creates these colder winters
that have been observed over Central Asia."
"Once
the jet stream gets into this wavier pattern, it sends wave energy up
into the highest levels of the atmosphere, which is called the
stratosphere, where we have the polar vortex, which is kind of
similar to the jet stream but it's much higher up in the atmosphere
and it travels much faster."
"So
as that wave energy gets sent up from this larger wave below, up into
the stratosphere, it breaks down that polar vortex so that it becomes
wavier as well. That wavier polar vortex sends energy back down to
the lower atmosphere and it creates an even wavier jet stream in
February."
"So
we're seeing this connection of mechanisms that starts with Arctic
sea ice loss and it makes a wavier jet stream for different reasons
all the way through winter."
Will
the jet stream continue to cause changes in climate?
By
identifying these mechanisms and linking them back directly to loss
of the Arctic sea ice, Dr Francis and her colleagues are
demonstrating how man-made global warming is creating feedbacks that
are changing the climate conditions in the northern hemisphere - and
not for the better.
It
may be counterintuitive, and it when it first happened it took
scientists by surprise - but now it looks like this is one of the
most important ways in which 'global warming' is hitting North
America. Melting ice in the Arctic Ocean is indirectly pushing frigid
Arctic air south across the continent, creating the perfect
conditions for massive snowfall.
Which
is all very well ... but what's coming next? "We are using these
climate models, or computer simulations ... to try and project what
we're expecting to see happen in the future, as greenhouse gases
continue to increase.
"The
early indications are that these large wavy patterns in the jet
stream are going to become more frequent in the future, as far as we
can tell. It is preliminary research that I haven't published yet but
it does look as if they are going to increase."
Nick
Breeze is
a film maker and writer on climate change and other environmental
topics. He has been interviewing a range of experts relating to the
field of climate change and science for over four years. These
include interviews with Dr James Hansen, Professor Martin Rees,
Professor James Lovelock, Dr Rowan Williams, Dr Natalia Shakhova, Dr
Michael Mann, Dr Hugh Hunt, among others.
Jennifer
Francis is
a research professor at the Institute of Marine and Coastal Sciences
at Rutgers University, where she studies Arctic climate change and
the link between Arctic and global climates. She has authored more
than 40 peer-reviewed publications on these topics. She was also the
co-founder of the Rutgers Climate and Environmental Change
Initiative.
Article
earlier posted at TheEcologist.org
Related
-
Wild Weather Swings
-
Buffalo’s Climate Change Driven Mega Snow-Flood
IPCC too conservative?
Sam
Carana
23
November, 2014
1. Ocean Heat
Below is what the IPCC says:
Below is what the IPCC says:
Below is a graph produced by Sam Carana, based on observations. For more background, see this earlier post.
2. Sea level Rise
The image below shows what the IPCC says.
If ocean heat will continues to rise as pictured in the image by Sam Carana, then thermal expansion alone will cause more sea level rise than foreseen by the IPCC. Furthermore, extensive melting on Antarctica and Greenland can result in additional sea level rise. Below is a sea level rise graph produced by Sam Carana, again based on observations, as discussed in this earlier post.
3. Arctic Sea Ice
The image below shows what the IPCC says.
If ocean heat will continues to rise as pictured in the image by Sam Carana, then Arctic sea ice will disappear much earlier than anticipated by the IPCC. An exponential trendline based on sea ice volume observations shows that sea ice looks set to disappear in 2019, while disappearance in 2015 is within the margins of a 5% confidence interval, reflecting natural variability.
A linear trend would be inappropriate, given the growing impact of feedbacks that can each be expected to reinforce sea ice decline, while there can also be interaction between these feedbacks, further accelerating sea ice decline. Albedo change is one such feedback, but there are numerous other ones, such as storms that have more chance to grow stronger as the area with open water increases.
In conclusion, an exponential trendline is more appropriate than a linear trendline, as also illustrated by above comparison, which shows that a linear trendline has 9 years fall outside its 95% confidence ionterval, versus 4 years for an exponential trendline. as discussed at the FAQ page.
Rapid decline of the snow and ice cover on the Northern Hemisphere is furthermore supported by rapidly rising surface temperatures over the Arctic, as well as greater intensity of heatwaves. Below is what the IPCC says on this.
Before further discussing surface temperatures, let's look into one of the feedbacks that could hugely increase temperatures, methane.
4. Methane
The IPCC appears to underestimate of the amount of methane that is contained in sediments under the Arctic Ocean and prone to be released as temperatures rise, as discussed in this earlier post.
The image below, from this earlier post, illustrates the threat that methane levels will rise rapidly.
5. Surface Temperatures
The IPCC expects that, worst case, global average temperature could rise by 13 degrees Celsius by 2300, as illustrated by the image below.
The situation could be much worse than foreseen by the IPCC, due to the non-linear way feedbacks can hugely increase temperature rises.
The threat is that such rapid temperature rises will appear at first in hotspots over the Arctic and eventually around the globe, while also resulting in huge temperature swings that could result in depletion of supply of food and fresh water, as further illustrated by the above image, from an earlier post, and the image below, from another earlier post.
The situation is dire and calls for comprehensive and effective action, as discussed at the Climate Plan blog.
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