It's a pretty impressive signal, and is clearly associated
with loss of the sea ice cover.
We also conduct two additional experiments
with loss of sea ice placed only in certain regions Subpolar sea ice loss vs. Polar sea ice loss).
Not exact matches
«Although a direct causal link has not been established between the atmospheric phenomena observed in late October 2012 and the record - breaking
sea -
ice loss observed during the preceding summer months, all
of the observations are consistent
with such an interpretation,» states the Oceanography article.
Dirk Notz and Julienne Stroeve have now compared corresponding model calculations
with data from satellite measurements, and discovered that the climate models underestimate the
loss of Arctic
sea ice.
WITH all the attention given to the
loss of sea ice in the Arctic, it's easy to forget that some
ice will persist for many years yet.
«Warming greater than 2 degrees Celsius above 19th - century levels is projected to be disruptive, reducing global agricultural productivity, causing widespread
loss of biodiversity and — if sustained over centuries — melting much
of the Greenland
ice sheet
with ensuing rise in
sea levels
of several meters,» the AGU declares in its first statement in four years on «Human Impacts on Climate.»
Those same lakes, along
with other evidence from around the world, also points to the shifting
of rain belts after a rapid
loss of Arctic
sea ice about 14,600 years ago that saw the Northern Hemisphere heat up faster than the Southern.
The researchers warn, however, that the future evolution
of the AMO remains uncertain,
with many factors potentially affecting how it interacts
with atmospheric circulation patterns, such as Arctic
sea ice loss, changes in solar radiation, volcanic eruptions and concentrations
of greenhouse gases in the atmosphere.
The recent string
of record - low winter maximums could be a sign that the large summer
losses are starting to show up more in other seasons,
with an increasingly delayed fall freeze - up that leaves less time for
sea ice to accumulate in winter, Julienne Stroeve, an NSIDC scientist and University College London professor, previously said.
Lead author Dr Malcolm McMillan from the University
of Leeds said: «We find that
ice losses continue to be most pronounced along the fast - flowing
ice streams
of the Amundsen
Sea sector,
with thinning rates
of between 4 and 8 metres per year near to the grounding lines
of the Pine Island, Thwaites and Smith Glaciers.»
The global mean temperature rise
of less than 1 degree C in the past century does not seem like much, but it is associated
with a winter temperature rise
of 3 to 4 degrees C over most
of the Arctic in the past 20 years, unprecedented
loss of ice from all the tropical glaciers, a decrease
of 15 to 20 % in late summer
sea ice extent, rising sealevel, and a host
of other measured signs
of anomalous and rapid climate change.
Many scientists concede that without drastic emissions reductions by 2020, we are on the path toward a 4C rise as early as mid-century,
with catastrophic consequences, including the
loss of the world's coral reefs; the disappearance
of major mountain glaciers; the total
loss of the Arctic summer
sea -
ice, most
of the Greenland
ice - sheet and the break - up
of West Antarctica; acidification and overheating
of the oceans; the collapse
of the Amazon rainforest; and the
loss of Arctic permafrost; to name just a few.
Joughin et al. (2010) applied a numerical
ice sheet model to predicting the future
of PIG, their model suggested ongoing
loss of ice mass from PIG,
with a maximum rate
of global
sea level rise
of 2.7 cm per century.
But from an email conversation
with Francis, Vavrus, and several other atmospheric scientists this week, it became clear that there may be more questions than answers at this point, given the large amount
of natural variability that affects winter weather patterns, and the very short observational record
of how the atmosphere responded to extreme
losses of sea ice (only five winters
of records since 2007).
There has been gradual melting and recession
of Arctic
sea ice with extreme
loss in 2007 rendering the Northwest Passage «fully navigable».
Our modelled values are consistent
with current rates
of Antarctic
ice loss and
sea - level rise, and imply that accelerated mass
loss from marine - based portions
of Antarctic
ice sheets may ensue when an increase in global mean air temperature
of only 1.4 - 2.0 deg.
The lag between decreases in
sea ice extent during late summer and changes in the mid-latitude atmospheric circulation during other seasons (when the recent
loss of sea ice is much smaller) needs to be reconciled
with theory.
Much
of the recent
sea ice loss is attributed to warmer
sea surface temperatures
with southerly wind anomalies a contributing cause [Francis and Hunter, 2007; Sorteberg and Kvingedal, 2006],
with thermodynamic coupling leading to associated increases in atmospheric moisture.»
From recent instrumental observations alone we are therefore unable to predict whether mass
loss from these
ice sheets will vary linearly
with changes in the rate
of sea - level rise, or if a non-linear response is more likely.
However, if the
loss of Arctic
Sea ice has significantly changed global atmospheric circulation patterns, then we are dealing
with a different system that has only been in existence since 2007, and we do not know how often to expect crop failures.
Global climate model projections (in CMIP3 at least) appear to underestimate
sea ice extent
losses with respect to observations, though this is not universally true for all models and some
of them actually have ensemble spreads that are compatible
with PIOMAS
ice volume estimates and satellite observations
of sea ice extent.
Thus, articles that link the
loss of Arctic
sea ice to global warming are acceptable, and any news article on Arctic
sea ice will generally touch on the role
of global warming — usually
with a mention for polar bears, which are indeed cute (not too cuddly, tho).
The coincidence
of this area
loss and a 30 square kilometer
loss in 2008
with abnormal warmth this year, the setting
of increasing
sea surface temperatures and
sea ice decline are all part
of a climate warming pattern.
The authors
of the study — Ricarda Winkelmann and Anders Levermann from the Potsdam Institute for Climate Impact Research, Ken Caldeira
of the Carnegie Institution for Science and Andy Ridgwell
of the University
of Bristol — find that the
loss of the entire Antarctic
ice sheet would take millenniums, but up to 100 feet
of sea level rise could result within 1,000 years,
with the rate
of the rise beginning to increase a century or two from now.
8) Accelerated mass
loss in Greenland and / or Antarctica, perhaps
with another huge
ice shelf breaking off, but in any case coupled
with another measurable rise in the rate
of sea level rise, 9) The Fifth Assessment Report (2012 - 2013) really spelling out what we face
with no punches pulled.
And the
loss of the
sea ice will mean the
loss of an entire ecosystem,
with repercussions that could include a major food chain, because
of organisms that live on the underside
of the
sea ice.
Last summer's record
loss of ice was due to a combination
of natural cycle and global warming factors: «more greenhouse gases, an unusual wind pattern, and warming
of the ocean water in regions
with reduced
sea ice.»
IIRC, the limit on mass
loss was attributed to the narrowness
of passes in the mountains, but if the
ice loss is behind the mountains as the ocean reaches beyond them, and mixes salt into the system
with tides, then only the flushing
of salt and icebergs via meltwater would limit the rate
of melt in the (brand new) Greenland
Sea.
He argued that the exceptionally cold snowy 2009 - 2010 winter in Europe had a connection
with the
loss of sea -
ice in the Arctic.
So, the positive feedback between melt and velocities implies that more melt leads to higher velocities, which bring in more
ice from cold regions to warm regions which increases the melt and hence the velocity etc,
with as a final result a rapid
loss of ice and hence an enhanced increased
sea level.
Here's how the summary put it: «The June 2010 Outlook indicates a continuation
of the overall trend in long - term
loss of summer Arctic
sea ice,
with no indication that a return to historical levels
of the 1980s / 1990s will occur.»
Indeed, the record - breaking
losses in the past couple
of years could easily be due to natural fluctuations in the weather,
with summer
sea ice increasing again over the next few years.
The fate
of sea ice in the Arctic Ocean is determined by a complicated mix
of factors, including the pressure changes,
with the biggest
loss of old thick
ice resulting more from a great «flush»
of floes than melting, Dr. Rigor and many other scientists tracking the region say.
In addition to the
loss of old thick
sea ice, the increased mobility of sea ice in the Beaufort Sea is consistent with the high sea ice mobility seen in the Atlantic sector by the drift of the «TARA» during the DAMOCLES experiment (Gascard, EOS, V
sea ice, the increased mobility
of sea ice in the Beaufort Sea is consistent with the high sea ice mobility seen in the Atlantic sector by the drift of the «TARA» during the DAMOCLES experiment (Gascard, EOS, V
sea ice in the Beaufort
Sea is consistent with the high sea ice mobility seen in the Atlantic sector by the drift of the «TARA» during the DAMOCLES experiment (Gascard, EOS, V
Sea is consistent
with the high
sea ice mobility seen in the Atlantic sector by the drift of the «TARA» during the DAMOCLES experiment (Gascard, EOS, V
sea ice mobility seen in the Atlantic sector by the drift
of the «TARA» during the DAMOCLES experiment (Gascard, EOS, Vol.
The problem I have
with the original post (yes intermediate) is what study was used to make the leap that despite
sea ice gains the thermal energy
of the warming oceans make its way through the
ice (which is an insulator) and causing land
ice loss.
The findings reinforce suggestions that strong positive
ice — temperature feedbacks have emerged in the Arctic15, increasing the chances
of further rapid warming and
sea ice loss, and will probably affect polar ecosystems,
ice - sheet mass balance and human activities in the Arctic...» *** This is the heart
of polar amplification and has very little to do
with your stated defintion
of amplifying the effects
of warming going on at lower latitudes.
Individual responses continue to be based on a range
of methods: statistical, numerical models, comparison
with previous rates
of sea ice loss, composites
of several approaches, estimates based on various non
sea ice datasets and trends, and subjective information (the heuristic category).
However, despite near normal rates
of ice loss during the month, June 2015 was a relatively warm month (Figure 7)
with 925 hPa air temperatures up to 2.5 C higher than average near the North Pole and East Siberian
Sea,
with even warmer air temperatures in the Kara
Sea (up to 4.5 C).
Individual responses continue to be based on a range
of methods: statistical, numerical models, comparison
with previous rates
of sea ice loss, estimates based on various non-
sea ice datasets and trends, and subjective information (the «heuristic» category).
At least relative to my questions above, what struck me was the possibility
of starting
with your reduction and analysis
of the snow cover / fall anomaly data to come up
with a research project based on some quite complicated but fascinating calculations on net TOA energy balance as a result
of your conclusion about the relation
of Arctic
sea ice loss to NH snow cover / amount anomaly.
Specifically «While natural chaotic variability remains a component
of mid-latitude atmospheric variability, recent
loss of Arctic
sea ice,
with its signature on mid-latitude atmospheric circulation, may load the dice in favor
of snowier conditions in large parts
of northern mid-latitudes.»
Provided that ocean and atmospheric conditions favor rapid melting in June and July, which we feel are still likely, it is therefore hypothesized that the 2013 fall
sea ice extent will achieve values comparable to those
of 2012,
with regional
losses governed by local wind and
ice conditions and dynamics.
«The changes are happening so fast in the Arctic —
with sea -
ice loss,
with increased time
of no snow cover — that that's really the driving feature.
If both Greenland and West Antarctica shed the entirety
of their
ice burden, global
sea levels would rise by 12 to 14 m. Although these icecaps would not disintegrate within a century, the
loss of even a third
of their mass — quite plausible if the rate
of polar
ice loss continues to double each decade — would force up the oceans by at least 4 m,
with disastrous socioeconomic and environmental consequences.
This means that the CO2 levels often associated
with a 2 ˚C rise — 450ppm — may just be the tipping point for the total
loss of all
ice sheets on the planet and a huge
sea - level rise.
The decrease in albedo that accompanies the
loss of sea ice is the phenom that underlies «arctic amplification» (as you point out, it has nothing directly to do
with sea level rise).
Point is that, the last couple
of years are not consistent
with the idea
of accelerating
ice loss and accelerating
sea level rise.
Global
sea levels could rise by more than 20 feet
with the
loss of shelf
ice in Greenland and Antarctica, devastating coastal areas worldwide.
With regard to Dr Tobis» observation that: «there's a something on the order
of a 10 % chance that we may have already passed the 2 C mark by any reasonable definition» the evidence
of a study
of Albedo
Loss published last January appears to put the issue beyond doubt: «Observational determination
of albedo decrease caused by vanishing Arctic
sea ice» (Kristina Pistone, Ian Eisenman, and V. Ramanathan)
The resulting enhanced
loss of summer and winter
sea ice resulted in feedbacks, associated
with Arctic Amplification, which has raised Arctic air temperatures at a rate twice the global average.