In order to make improved projections, scientists are fine - tuning their understanding of the many influences
on sea ice trends, including both manmade global warming and natural climate variability.
Not exact matches
Since at least 1979, Arctic
sea ice has generally been
on a downward slope,
trending 4.5 percent lower per decade overall and 13.7 percent lower per decade during the September summer minimum.
The authors of a new study reviewing the volume data, detailed
on Monday in the journal Nature Geoscience, are quick to caution, though, that one single year of rebound doesn't suggest any
sea ice recovery, as the overall
trend is still downward.
But as an explanation of what they're up to: «
ICES 1999 Annual Science Conference CM 1999 / L: 19 Nordic
Seas Exchanges The Deep Overflow through the Faroe Bank Channel» In this paper he doesn't make any firm commitment to
trends, but notes «a slight indication of a decreasing
trend in ISOW transport»; «as yet the ADCP measurements in the Faroe Bank Channel are of too short duration to allow any conclusions
on this important question.»
IPCC / NSIDC
trends [based
on SIE
sea ice extent] underestimate the real speed of ASI loss — true / false / maybe.
Those who think that there's nothing to worry about, because
sea ice might recover
on its own accord, are requiring some negative forcing or feedback effect to come into play, to make the PIOMAS
trend line do a U-turn.
andy, from your above - referenced article
on sea -
ice trends: «But another factor was probably involved, one with roots going back to about 1989.
I recommend you check out my recent piece
on sea -
ice trends in Science Times.
However your comment
on Maslowski has combined with my scanning the papers Hank linked to earlier in this thread;
trend extrapolation using both PIOMAS and NPS are being used to assert that the Arctic is
on a fast track to seasonally
sea -
ice free state.
[Andy Revkin —
On Arctic ice trends, I have a post coming shortly on the latest update from the world's leading teams of sea ice experts, showing this year's retreat is unlikely to match last year's, while the long - term trend is still heading toward ever less summer ic
On Arctic
ice trends, I have a post coming shortly
on the latest update from the world's leading teams of sea ice experts, showing this year's retreat is unlikely to match last year's, while the long - term trend is still heading toward ever less summer ic
on the latest update from the world's leading teams of
sea ice experts, showing this year's retreat is unlikely to match last year's, while the long - term
trend is still heading toward ever less summer
ice.
On Mr. Will's defense of his accuracy, particularly on trends in sea ice at both poles as they related to global warming, it's worth pointing out a few thing
On Mr. Will's defense of his accuracy, particularly
on trends in sea ice at both poles as they related to global warming, it's worth pointing out a few thing
on trends in
sea ice at both poles as they related to global warming, it's worth pointing out a few things.
It's also interesting to read the caution with which scientists discussed Arctic
sea ice in this August 2000 NYT article — they clearly expect to see interannual variations superimposed
on a longer - term
trend.
Unfortunately, the tough scientific work to clarify
ice and
sea trends and dynamics has largely been obscured online by coverage focused
on an error
on Greenland
ice loss that many polar scientists say made it into the new edition of the Times Comprehensive Atlas of the World (that's the British Times, just to be clear).
If you plot the average Arctic
Sea Ice extent for 20 years, the you should also plot the monthly maximum and minimum values
on the same figure so that we can get some perspective
on where the 2007 and 2008 data falls in the context of annual variability, or examine for
trends.
A significant northward
trend (reduction of
ice) in the winter - maximum
ice edge is apparent, however, and appears to be caused by the gradual warming of
sea - surface temperatures in the region (paper available
on this if you want it).
The Arctic Climate Impact Assessment, the Intergovernmental Panel
on Climate Change (whose reports are conservative by nature), and a range of other assessments all conclude with high confidence that — for better or worse — the long - term Arctic
trend for summer
sea ice is down, given the projected buildup of greenhouse gases and tendency of the Arctic to amplify warming.
So the main issue for me is that all «serious» studies show only «statistical
trends» having some effects
on some measurable quantities, (slight increase of average temperature, slight increase of
sea level, slight decrease of northern, but not southern,
sea ice,..)
You can find out more (and see links to my earlier coverage of Arctic
sea -
ice trends, and what's going
on with
sea ice at the other end of the planet) in my latest post
on Dot Earth.
Published
trends in peer - reviewed articles
on Antarctic
sea ice extent (all
on annual average extent):
None of the
sea -
ice specialists I've interviewed since 2000
on Arctic
trends ever predicted a straight - line path to an open - water Arctic, but quite a few have stressed the longstanding idea that as white
ice retreats, solar energy that would have been reflected back into space is absorbed by the dark
sea, with that heat then melting existing
ice and shortening the winter frozen season.
Here's the global
sea ice trend, combining what's going
on up north and down south.
The
sea ice grows and recedes with the seasons every year and has been
on the decline since spring... and the overall
trend over time is definitely downward.
Canadian
Ice Service, 4.7, Multiple Methods As with CIS contributions in June 2009, 2010, and 2011, the 2012 forecast was derived using a combination of three methods: 1) a qualitative heuristic method based on observed end - of - winter arctic ice thicknesses and extents, as well as an examination of Surface Air Temperature (SAT), Sea Level Pressure (SLP) and vector wind anomaly patterns and trends; 2) an experimental Optimal Filtering Based (OFB) Model, which uses an optimal linear data filter to extrapolate NSIDC's September Arctic Ice Extent time series into the future; and 3) an experimental Multiple Linear Regression (MLR) prediction system that tests ocean, atmosphere and sea ice predicto
Ice Service, 4.7, Multiple Methods As with CIS contributions in June 2009, 2010, and 2011, the 2012 forecast was derived using a combination of three methods: 1) a qualitative heuristic method based
on observed end - of - winter arctic
ice thicknesses and extents, as well as an examination of Surface Air Temperature (SAT), Sea Level Pressure (SLP) and vector wind anomaly patterns and trends; 2) an experimental Optimal Filtering Based (OFB) Model, which uses an optimal linear data filter to extrapolate NSIDC's September Arctic Ice Extent time series into the future; and 3) an experimental Multiple Linear Regression (MLR) prediction system that tests ocean, atmosphere and sea ice predicto
ice thicknesses and extents, as well as an examination of Surface Air Temperature (SAT),
Sea Level Pressure (SLP) and vector wind anomaly patterns and trends; 2) an experimental Optimal Filtering Based (OFB) Model, which uses an optimal linear data filter to extrapolate NSIDC's September Arctic Ice Extent time series into the future; and 3) an experimental Multiple Linear Regression (MLR) prediction system that tests ocean, atmosphere and sea ice predicto
Sea Level Pressure (SLP) and vector wind anomaly patterns and
trends; 2) an experimental Optimal Filtering Based (OFB) Model, which uses an optimal linear data filter to extrapolate NSIDC's September Arctic
Ice Extent time series into the future; and 3) an experimental Multiple Linear Regression (MLR) prediction system that tests ocean, atmosphere and sea ice predicto
Ice Extent time series into the future; and 3) an experimental Multiple Linear Regression (MLR) prediction system that tests ocean, atmosphere and
sea ice predicto
sea ice predicto
ice predictors.
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).
WMO will issue its full Statement
on the State of the Climate in 2017 in March which will provide a comprehensive overview of temperature variability and
trends, high - impact events, and long - term indicators of climate change such as increasing carbon dioxide concentrations, Arctic and Antarctic
sea ice,
sea level rise and ocean acidification.
Canadian
Ice Service, 4.7 (+ / - 0.2), Heuristic / Statistical (same as June) The 2015 forecast was derived by considering a combination of methods: 1) a qualitative heuristic method based on observed end - of - winter Arctic ice thickness extents, as well as winter Surface Air Temperature, Sea Level Pressure and vector wind anomaly patterns and trends; 2) a simple statistical method, Optimal Filtering Based Model (OFBM), that uses an optimal linear data filter to extrapolate the September sea ice extent timeseries into the future and 3) a Multiple Linear Regression (MLR) prediction system that tests ocean, atmosphere and sea ice predicto
Ice Service, 4.7 (+ / - 0.2), Heuristic / Statistical (same as June) The 2015 forecast was derived by considering a combination of methods: 1) a qualitative heuristic method based
on observed end - of - winter Arctic
ice thickness extents, as well as winter Surface Air Temperature, Sea Level Pressure and vector wind anomaly patterns and trends; 2) a simple statistical method, Optimal Filtering Based Model (OFBM), that uses an optimal linear data filter to extrapolate the September sea ice extent timeseries into the future and 3) a Multiple Linear Regression (MLR) prediction system that tests ocean, atmosphere and sea ice predicto
ice thickness extents, as well as winter Surface Air Temperature,
Sea Level Pressure and vector wind anomaly patterns and trends; 2) a simple statistical method, Optimal Filtering Based Model (OFBM), that uses an optimal linear data filter to extrapolate the September sea ice extent timeseries into the future and 3) a Multiple Linear Regression (MLR) prediction system that tests ocean, atmosphere and sea ice predicto
Sea Level Pressure and vector wind anomaly patterns and
trends; 2) a simple statistical method, Optimal Filtering Based Model (OFBM), that uses an optimal linear data filter to extrapolate the September
sea ice extent timeseries into the future and 3) a Multiple Linear Regression (MLR) prediction system that tests ocean, atmosphere and sea ice predicto
sea ice extent timeseries into the future and 3) a Multiple Linear Regression (MLR) prediction system that tests ocean, atmosphere and sea ice predicto
ice extent timeseries into the future and 3) a Multiple Linear Regression (MLR) prediction system that tests ocean, atmosphere and
sea ice predicto
sea ice predicto
ice predictors.
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).
Most of the studies
on the Arctic climate and
ice trends cited to support the proposed listing assumed that the buildup of heat - trapping gases was probably contributing to the loss of
sea ice, or that the continued buildup of these gases, left unchecked, could create
ice - free Arctic summers later this century, and possibly in as little as three decades.
Generally yes, but there has been a lot of new information learned since the IPCC Third Assessment Report (e.g.,
on trends in hurricane intensity, the accelerated melting back of Arctic
sea ice, the intensifying deterioration of the edges of the Greenland Ice Sheet, etc.) and Gore's presentation of the science has been updated to account for these, drawing from what are the really highly reviewed and high quality papers by leading scientis
ice, the intensifying deterioration of the edges of the Greenland
Ice Sheet, etc.) and Gore's presentation of the science has been updated to account for these, drawing from what are the really highly reviewed and high quality papers by leading scientis
Ice Sheet, etc.) and Gore's presentation of the science has been updated to account for these, drawing from what are the really highly reviewed and high quality papers by leading scientists.
I argued that Greenland's glaciers would soon stabilize and
sea ice in the Barents Sea would soon recover based on trends in the transport of warm Atlantic water into the Arct
sea ice in the Barents
Sea would soon recover based on trends in the transport of warm Atlantic water into the Arct
Sea would soon recover based
on trends in the transport of warm Atlantic water into the Arctic.
Over the long - term, melting of the West Antarctic
Ice Sheet could yield as much as 10 to 14 feet of global average
sea level rise, with local
sea level rise varying considerably depending
on land elevation
trends, ocean currents and other factors.
But
on the contrary, the Southern Ocean has warmed by around 0.5 °C in the three decades since satellites began measuring
sea ice trends.
That's consistent with other research
on longer term
trends in Greenland
ice, and how these
trends contribute to
sea level rise.
Since current
ice melt data could indicate variable climate
trends and aren't necessarily part of an accelerating
trend, the study warned that predictions of future
sea - level rise should not be based
on measurements of glacial loss» Daily Mail.
ocean temperatures, widespread melting of snow and
ice, and rising global average
sea level,» are three disjoint sources of confirmation that give us reliable enough
trend information to establish consilience about what we may say after 2005
on HadCRUT4.
As of this writing, there is observational and modeling evidence that: 1) both annular modes are sensitive to month - to - month and year - to - year variability in the stratospheric flow (see section
on Stratosphere / troposphere coupling, below); 2) both annular modes have exhibited long term
trends which may reflect the impact of stratospheric ozone depletion and / or increased greenhouse gases (see section
on Climate Change, below); and 3) the NAM responds to changes in the distribution of
sea -
ice over the North Atlantic sector.
These regional
trends together yield a small increase, so studying each region will help scientists get a better grasp
on the processes affecting
sea ice there.
-- and if not, how can one zero in
on an effect like
trends in the amount of
sea ice?
RCP 2.6 and a realistic model based
on past
sea ice extent and its relationship to AMO are indistinguishable and do not anticipate an Arctic free of
ice within the 21st century if current
trends are maintained.
Canadian
Ice Service; 5.0; Statistical As with Canadian Ice Service (CIS) contributions in June 2009 and June 2010, the 2011 forecast was derived using a combination of three methods: 1) a qualitative heuristic method based on observed end - of - winter Arctic Multi-Year Ice (MYI) extents, as well as an examination of Surface Air Temperature (SAT), Sea Level Pressure (SLP) and vector wind anomaly patterns and trends; 2) an experimental Optimal Filtering Based (OFB) Model which uses an optimal linear data filter to extrapolate NSIDC's September Arctic Ice Extent time series into the future; and 3) an experimental Multiple Linear Regression (MLR) prediction system that tests ocean, atmosphere, and sea ice predicto
Ice Service; 5.0; Statistical As with Canadian
Ice Service (CIS) contributions in June 2009 and June 2010, the 2011 forecast was derived using a combination of three methods: 1) a qualitative heuristic method based on observed end - of - winter Arctic Multi-Year Ice (MYI) extents, as well as an examination of Surface Air Temperature (SAT), Sea Level Pressure (SLP) and vector wind anomaly patterns and trends; 2) an experimental Optimal Filtering Based (OFB) Model which uses an optimal linear data filter to extrapolate NSIDC's September Arctic Ice Extent time series into the future; and 3) an experimental Multiple Linear Regression (MLR) prediction system that tests ocean, atmosphere, and sea ice predicto
Ice Service (CIS) contributions in June 2009 and June 2010, the 2011 forecast was derived using a combination of three methods: 1) a qualitative heuristic method based
on observed end - of - winter Arctic Multi-Year
Ice (MYI) extents, as well as an examination of Surface Air Temperature (SAT), Sea Level Pressure (SLP) and vector wind anomaly patterns and trends; 2) an experimental Optimal Filtering Based (OFB) Model which uses an optimal linear data filter to extrapolate NSIDC's September Arctic Ice Extent time series into the future; and 3) an experimental Multiple Linear Regression (MLR) prediction system that tests ocean, atmosphere, and sea ice predicto
Ice (MYI) extents, as well as an examination of Surface Air Temperature (SAT),
Sea Level Pressure (SLP) and vector wind anomaly patterns and trends; 2) an experimental Optimal Filtering Based (OFB) Model which uses an optimal linear data filter to extrapolate NSIDC's September Arctic Ice Extent time series into the future; and 3) an experimental Multiple Linear Regression (MLR) prediction system that tests ocean, atmosphere, and sea ice predicto
Sea Level Pressure (SLP) and vector wind anomaly patterns and
trends; 2) an experimental Optimal Filtering Based (OFB) Model which uses an optimal linear data filter to extrapolate NSIDC's September Arctic
Ice Extent time series into the future; and 3) an experimental Multiple Linear Regression (MLR) prediction system that tests ocean, atmosphere, and sea ice predicto
Ice Extent time series into the future; and 3) an experimental Multiple Linear Regression (MLR) prediction system that tests ocean, atmosphere, and
sea ice predicto
sea ice predicto
ice predictors.
Is there a reason why a linear
trend is shown for the NH
sea ice extent, where a second order polynomial fit trend is shown on the Arctic Sea Ice Escalator graph
sea ice extent, where a second order polynomial fit trend is shown on the Arctic Sea Ice Escalator graph
ice extent, where a second order polynomial fit
trend is shown
on the Arctic
Sea Ice Escalator graph
Sea Ice Escalator graph
Ice Escalator graphic?
This assessment is based
on a subset of models that most closely reproduce the climatological mean state and 1979 to 2012
trend of Arctic
sea ice cover.
2012's
sea ice area and extent were already
trending low this year, but damage done to the thin and low concentration of
ice by this storm almost ensures that 2012 will eclipse 2007 in all categories as the lowest
sea ice on record by the time the September low is set.
Not only does this low - pressure area, or cyclone, look bigger, more intense and longer - lasting than the one from last year, the
ice also seems to be in a weaker state than ever, as evidenced by the fact that 2012
trend lines
on both
sea ice area and
sea ice extent graphs track lower than previous record years, despite weather that until recently would completely stall the decline.
As for Antarctic
sea ice, that's very interesting and very likely related to the wind
trends and their effect
on the polar gyres.
Since the tropical oceans have flattened out and solar does have its largest impact
on the tropical oceans, I would expect about the same possibly some increase in Arctic
sea ice over the next decade Not a consistent increase by any means, but I doubt it will make it to the 2 mkm ^ 2 and will
trend towards a 6 million km ^ 2 average which is hardly «
ice free».
IPCC synthesis reports offer conservative projections of
sea level increase based
on assumptions about future behavior of
ice sheets and glaciers, leading to estimates of
sea level roughly following a linear upward
trend mimicking that of recent decades.
``... examination of records of fast
ice thickness and
ice extent from four Arctic marginal
seas (Kara, Laptev, East Siberian, and Chukchi) indicates that long - term
trends are small and generally statistically insignificant, while
trends for shorter records are not indicative of the long - term tendencies due to strong low - frequency variability in these time series, which places a strong limitation
on our ability to resolve long - term
trends....
Stern: My estimate for September average
sea ice extent (4.67 million square kilometers) was simply based
on extrapolation of the 10 - year
trend (1989 - 2008).
Actually Fielding's use of that graph is quite informative of how denialist arguments are framed — the selected bit of a selected graph (and don't mention the fastest warming region
on the planet being left out of that data set), or the complete passing over of short term variability vs longer term
trends, or the other measures and indicators of climate change from ocean heat content and
sea levels to changes in
ice sheets and minimum
sea ice levels, or the passing over of issues like lag time between emissions and effects
on temperatures... etc..