Will Greenland Begin Accumulating Ice in 2015 and Beyond?

Guest post by Jim Steele, director emeritus Sierra Nevada Field Campus, San Francisco State University.

Based on NOAA’s 2014 Arctic Report Card, the past 2 decades of ice loss in Greenland has slowed dramatically in 2013-2014. In contrast to Velicogna’s (2014) previously published average mass loss of 280 +/-58 gigatons/year using GRACE satellite data, or the maximum loss of 570 gigatons in 2012-2013, there was only an insignificant loss of 6 gigatons from June 2013 to June 2014, or mere 1% of the previous year’s loss. A loss of 360 gigatons translates into a 1 millimeter rise in sea level, therefore the 2013-2014 sea level rise should be 1.3 mm less than the year before. And based on historical analyses, Greenland will likely begin gaining mass in the coming years.

In Vanishing Ice Most Likely All Natural (transcipt here) 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 Arctic. Although a one-year recovery is much too short a period from which to derive reliable projections, it is exactly what natural climate dynamics predict.

Based on GRACE satellite gravity estimates (illustrated in the graph below on the left) and hydrographic measurements (graph on right), Greenland’s lost ice has correlated best with the pulses of warm Atlantic water that entered into the Irminger Current that flows to the west around Greenland, delivering relatively warm water to the base of Greenland’s marine terminating glaciers. (Temperatures of the Irminger warm pulse are represented by the numbers graph on the right.) Marked by the red arrow most of Greenland’s ice loss has happened in the southeast region, precisely where the brunt of warm subsurface waters entered the Irminger Current. Accordingly Kahn (2014) reported between 2003 -2006 that 50 % of the total ice loss of the Greenland Ice Sheet occurred in southeast Greenland, and thinning and calving of just 2 glaciers (marked HG) and (KG) accounted half of that loss. Thinning and calving are driven primarily by submarine melting. Although NOAA highlights Greenland’s surface melt rates, Rignot (2009) report that rates of iceberg discharge and rates of “submarine melting are two orders of magnitude larger than surface melt rates.”

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Researchers have measured the inflow of warm Atlantic waters along a line between Scotland and the Irminger Sea (A. below) and have determined how that water was partitioned between flows entering the Irminger Current and the flows entering the basins that feed the Barents Sea. Using satellite altimetry to measure changes in sea level, Chafik (2014) reported the flow of warm Atlantic waters into the Irminger Current had increased significantly between 1992-1998 (B. below), but over the past 18 years the volume of warm water has been declining. Accordingly researchers had reported that large glaciers, like the Jakobshavn with submarine grounding points, had been stable or advancing between the 1960s and early 1990s. Then coincident with the arrival of a warmer water via the Irminger Current, the glaciers abruptly began retreating. Since 1997 the loss of Greenland ice accelerated culminating in the widely trumpeted loss of 570 gigatons in 2012-2013, which was opportunistically portrayed as evidence of CO2 warming.

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Because the inflow of warm water has been waning since the late 1990s, it suggested that accelerated loss of ice would soon wane as well. Based on the drop in sea level (B. above) the volume of intruding warm Atlantic water has decreased by 10%. If the previous pulse of warm water has been the driving force for retreating Greenland glaciers and melting Barents Sea ice, then that reduced inflow predicts Greenland’s glaciers should soon stabilize while Barents Sea ice begins to recover. Indeed 2014 also witnessed an increase in Barents Sea ice. Likewise NOAA’s 2014 Arctic Report card also stated the “coverage of multiyear ice in March 2014 increased to 31% of the ice cover from the previous year’s value of 22%.” Suggesting more ice is surviving the melt season. In addition the mean sea-ice thickness in multiyear ice zone along northwest Greenland has increased by 0.38 m.

But why did the loss of Greenland ice continue to accelerate after the initial 90s pulse of warm water intrusions? The warm intruding Atlantic water is saltier and denser and flows between 100 and 900 meters below the surface. The weight of the glaciers have depressed the continental shelf so it slopes towards the shore (similar to the condition illustrated below for Antarctica’s Amundsen Sea glaciers.). When pulses of warm water are strong enough to rise over the shelf’s outer ridge, that warm dense water then flows downward to the grounding point of the glacier and remains there until a new equilibrium is established via basal melting and a retreating grounding point. Increased basal melting also increases calving of the floating ice shelf and the loss of buttressing power that inhibits the glaciers’ seaward flow. The end result is the glaciers accelerate seaward, causing dynamic thinning, increased calving, and a large loss of ice mass that continues until a new equilibrium is established. The continued reduction of warm water inflows and the dramatic reduction of lost ice mass in 2014, now suggest the glaciers are no longer adjusting to the previous warm water intrusions.

clip_image007

Before the Little Ice Age (LIA), Greenland’s glaciers, like the Jakobshavn, were smaller than seen in the present day (Young 2011). During the Little Ice Age between ~1400 and 1850, glaciers grew to their maximum Holocene extent. That LIA advance correlates with 1) lower solar flux, 2) decreased inflows of warm Atlantic water, and 3) a more persistent negative North Atlantic Oscillation. Although topographical features of Greenland’s glaciers will cause each glacier to adjust in a unique manner, overall the recent decrease in solar flux approaching LIA levels, the current decline in warm water inflows, and the current trend to a more persistent negative North Atlantic Oscillation all suggest that Greenland will begin accumulating ice mass over the next decade.

In Ocean Gyre Circulation Changes Associated with the North Atlantic Oscillation (NAO)

Curry (2001) created a Transport Index illustrating the correlation between the pole-ward transport of warm tropical water and the North Atlantic Oscillation. As seen in their illustration, there was a rapid increase in the pole-ward transport during the 80s and 90s when the NAO was in an increasingly positive phase. In general agreement but supplemented by other atmospheric dynamics, Barrier (2014) suggest increased transport is due to the spin-up of the subtropical gyre during the persistent positive NAO and reduced transport follows a spin-down during persistent NAO- conditions.

clip_image008

 

So why didn’t Greenland’s glaciers begin retreating earlier during the 1980s and 90s? When the NAO is positive, both the sub-Tropical gyre (STG in the illustration below) and the sub-Polar gyre (SPG) speed up and expand. While the spin-up of the sub-Tropical gyre transports more tropical water pole-ward, in contrast the expanded sub-Polar gyre limits how much warm water will enter the Arctic seas. This quasi-blocking effect causes more warm water to be re-circulated equator-ward and stored in the sub-Tropical gyre. The amount of warm water entering the Irminger Current is particularly limited because the sub-Polar gyre also shunts the pole-ward transport to the east towards the Barents Sea. When the NAO first enters a negative phase the sub-Polar gyre contracts towards the west, allowing more warm water to enter the Irminger Sea.

clip_image010

Statistical studies have debated the correlation between retreating Arctic ice and the negative NAO because it generates a confounding short term warming trend that is contradicted by the longer cooling trend suggested for the LIA as well as observed during the 1960s and 70s. But that contradiction is easily explained by the effects of an expanding and contracting sub-Polar gyre (SPG). The initial contraction of the SPG during the early negative NAO allows more warm water to enter the Arctic. However the negative NAO also implies a spin-down of the subtropical gyre and therefore a drop in the pole-ward transport of warm tropical waters. Thus as the negative NAO persists, the initial warm pulse into the Arctic is exhausted and followed by cooling trend decades later. A similar scenario was reported by Bengtsson (2004) in The Early Twentieth-Century Warming in the Arctic—A Possible Mechanism to explain the rapid 1930s and 40s warming of the Arctic and retreat of Greenland glaciers that persisted into the early phase of the negative NAO. With all things considered, the evidence strongly suggests we will soon witness a similar natural cycle and a rebound in the Greenland’s ice.

The essay is adapted and updated from Landscapes and Cycles: An Environmentalist’s Journey to climate Skepticism.

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December 29, 2014 9:09 pm

When will they ever learn to go looking for all wind streams as well as water staiths/systems….. Not half of what’s needed is in the article above.
But yes due to the volcano activity south Barent’s Straith and on Iceland the last 24 months the temperature once again will fall and glaciers grow more than their usual season changes.

Charles Nelson
December 29, 2014 9:11 pm

Just to be clear. Are we now to accept the data from ‘Grace’ which I had always understood to be nearly worthless?

Reply to  Charles Nelson
December 29, 2014 9:36 pm

Charles the problem with GRACE data is that it relies in isostatic adjustments which rely on estimates of past ice volumes and how the earth’s crust has rebounded. Different authors use different models to make those adjustments so comparing results from different models are not trustworthy. That said, we can get fairly reliable year to year estimates of mass change if the same modeling adjustments are consistently used.

Charles Nelson
Reply to  jim Steele
December 29, 2014 11:48 pm

Thanks!

JohnB
Reply to  jim Steele
December 29, 2014 11:50 pm

Jim, the question I’ve never seen answered is “How do we differentiate what GRACE is measuring?”.
Can somebody explain how we know that the change in gravity is due to a change in mass in the top 2 metres of ice and not a change in the mass of the 3,000 klm of liquid and extremely dense rock underneath?
I’m willing to give GRACE a fair chance and am happy to agree that it accurately rec9ords the change in mass between the satellite and the Centre of the Earth. But until someone can say how we decide exactly where on that line the change occurs then I’m sceptical of the interpretations of the data.

David A
Reply to  jim Steele
December 30, 2014 2:42 am

John B, indeed! That plus the disparate modeled isostatic adjustments possibly mean we do not know the sign. However as Jim S points out, as long as the adjustments are consistent, we may be getting a reasonable idea of the change. (even if we initially get the sign wrong) However that is only true ” if the same modeling adjustments are consistently used.” In “Climate Science” the methods often change if the results are not favorable.

johnmarshall
Reply to  jim Steele
December 30, 2014 4:00 am

Thanks for a good post. Got the book, excellent.

Reply to  Charles Nelson
December 30, 2014 8:47 am

I’m on that page as well. Two satellites in orbit and they speed up and slow down relative to each other based on gravity. That’s a pretty coarse chunk of data that is supposed to be able to map the loss of a total of a third of a meter of ice a year (327kg/m²/year average) on top of a ball of dynamic molten iron and molten rock with a thin rocky crust massing 5.97×10^24 kg. In a geologically active area where magma movement is likely to provide an extremely noisy environment for an “instrument” that has a spherical measurement field that includes our moon, local star and other planetary bodies in our solar system… all of which have to be subtracted our just to isolate our planet.

David
Reply to  nielszoo
December 30, 2014 2:19 pm

The Earth’s mantle, which accounts for the great majority of the ‘rock’, is not molten. Over long time scales it behaves like a very viscous fluid. I don’t know whether convection currents in the mantle would be sufficient to influence gravity measurements on a decadal scale, but the stuff is not sloshing around like water.

JohnB
Reply to  nielszoo
December 30, 2014 5:02 pm

David, not sloshing around like water no. However with constant isostatic movement and the removal of material through volcanic action it must be perforce moving around on a decadal scale. When the crust is pushed down it moves immediately, not in 1,000 years.
The point is simply that the entire Earth is in constant flux and a very small movement will swamp the ice signal.
Perhaps the signal is normalised by comparing it to the changes in gravity noticed over deserts and other rocky but uninhabited areas. I don’t know, that’s why I’m asking. I’ve looked, I can’t find the information.

Duster
Reply to  nielszoo
December 31, 2014 6:01 pm

If you look at the animations on the GRACE wiki, talking about anomalies on Greenland without considering the rest of the planet is silly. It is plain that the surface of the geoid (a calculated gravitational equipotential surface) varies a lot through through fairly short time scales (less than a decade). There are huge anomalies of both signs in the Amazon basin for instance that come and go, so pointing to ice loss on Greenland is potentially absurd.

December 29, 2014 9:17 pm

We are in a solar sunspot minimum through 2030. There should at least be a slowing of melt and depending on snow accumulation and colder temperatures during the summer, we might see some larger ice fields that eventually give way to glacier growth.
It will be an interesting 15 years.
Paul

December 29, 2014 9:31 pm

Reblogged this on Public Secrets and commented:
And another climate-alarmist claim begins to look dodgy, this time about the receding of Greenland’s glaciers. Click through for the details, but the gist is –say it after me– “natural cycles.”

Reply to  Phineas Fahrquar
December 30, 2014 8:25 am

Thanks for re-blogging

December 29, 2014 10:18 pm

The AGW crowd has been pinning their hopes on a UNFCCC CO2 emissions deal to curb CO2 output so they could claim a causality connection with the coming natural cooldown with its ice-recoveries at both poles. So now, it looks like global cooling is going to leave the dock without the CAGW ship of fools as passengers along for the free ride.
The expression that comes to mind is, “When the tide goes out, we’ll see who has been swimming naked.”

Jimbo
Reply to  Joel O’Bryan
December 30, 2014 1:08 am

GLOBAL Co2 output continues to shoot up and will continue for the foreseeable future no matter what deal they break. They cannot claim credit for something they have failed to do – curb global co2 output.
We know we had an 1920s to 1940s Arctic Warm Period between around 1920 to 1940. We don’t know for sure what the Arctic extent actually was (disputed), and we do know there was Greenland glacier retreat as fast, if not faster than the 2000s.
http://beta.dmi.dk/uploads/tx_dmidatastore/webservice/b/m/s/d/e/accumulatedsmb.png

JohnB
Reply to  Jimbo
December 30, 2014 5:10 pm

Jimbo, people like to feel important. They ignore the rapidly developing second and third worlds. If their nation drops CO2 output by 1% and the temps stabilise or go down, the local Greens will claim victory.
Notice how the CO2 advocates talk about the US, Europe, Australia and occasionally China. The 2.4 billion people without electricity who want it and will have it by 2100 are never mentioned. Perhaps because it shows just how irrelevant the actions or non actions of 23 million Australians or even 300 million Americans really are.

Bill Illis
Reply to  Joel O’Bryan
December 30, 2014 5:11 am

One should be careful about what “mass balance” is being talked about.
Mass Balance = Surface Mass Balance – Discharge – Ice-Shelf Bottom Changes
Mass Balance = [Precipitation/Accumulation – Runoff – Sublimation] – Discharge (ice-bergs, calving etc) – Ice-Shelf Bottom Changes/Melting/Refreezing
Sometimes people, especially the pro-warming exaggerators, are only referring to 1 of the 5 components (or just 3 of the 5 components etc). It is better to include all of them and/or be careful about what is being referred to when it comes to ice mass balance numbers.
I don’t think the scientists using Grace are using the newest glacial isostatic rebound models for Greenland from the GPS measurements which resulted in substantial changes from the previous models (cutting the mass balance loss rates by 33% to 50%).

Reply to  Bill Illis
December 30, 2014 8:43 am

In deed the NOAA report card focuses on surface mass balance along a specific transect and their focus implies atmospheric warming drives the overall ice balance.That’s why using GRACE data is required as it points out the local nature of ice dynamics and its overall significance. GRACE data largely unveiled the fact that most of Greeland’s mass change was happening near the coast.
Regards Grace GIA adjustment models Velicogna (2014) uses “The glacial isostatic adjustment (GIA) signal, is subtracted from the GRACE data. In Antarctica we use Ivins et al. [2013]’s regional ice deglaciation model combined with ICE-5G for the rest of the globe. In Greenland we use Simpson et al. [2009]’s regional ice deglaciation model combined with ICE-5G outside Greenland.”
Based on earlier papers like Velicogna, I. and J. Wahr. 2006: Significant acceleration of Greenland ice mass loss in spring, 2004: Nature, 443 that NOAA references GRACE has been using the ICE-5G model for over a decade.

ironicman
December 29, 2014 10:46 pm
December 29, 2014 11:12 pm

That Greenland will begin accumulating ice in 2015 is a very bold prediction and it will be interesting to look back a year from now to see if this article makes any sense or not.
My prediction is that it won’t. I think it would be very surprising if the glaciers started to grow, unless the global temperatures drop back to where they were pre 1990.
Let’s see next year.
/Jan

Reply to  Jan Kjetil Andersen
December 30, 2014 1:52 pm

Until next year. But the sea surface height/ warm water intrusions suggest warm water inflows have retreated to the early 1990s state.

jones
December 29, 2014 11:14 pm

All consistent with surely?

Editor
December 29, 2014 11:16 pm

This is true ONLY for those short glaciers along the Greenland coastal mountains: 10 to 25 km inland in about their maximum length.
The inland icecaps remain stationary (increasing 246 feet in thickness between WWII and 1990’s for example) but NOT flowing out to sea as in the diagram. The inland ice cap is trapped between the coastal mountain ranges, and cannot flow towards sea. The coastal mountain glaciers can, and do, of course flow downhill as shown in the simplified diagram above. But! Those coastal glaciers are a very, very small amount of the total Greenland ice mass.
Note also that there is very, very little sea ice around Greenland. But just the “excess” sea ice around Antarctica this June was 2.06 million sq km’s => This “excess” Antarctic sea ice anomaly was alone equal to the entire area of Greenland (2.16 Mkm^2).
Further, the inverted grounding line on the seafloor will act opposite the effect described: If, for example, the glacier ice leaving the continent/island thickens, the grounding line is moved further inland because the ice shelf hits the sloped bottom faster (earlier) in its final path. Thus, one could argue that in specific areas of a sloping sea floor like that shown – areas like the Pine Island Glacier, Thwaites glacier, and the hypothetical glacier drawn above – today’s glacier ice is thicker, the glacier hits the sloping bottom earlier (closer to land) and therefore we have more ice mass present.
Not less, as a first level, ice area = ice mass average might imply if you assume a constant glacier thickness through all of history..

Mike McMillan
Reply to  RACookPE1978
December 30, 2014 2:59 am

When I was flying that route back 2001-2006 there was always a lot of icebergs along the eastern coast, south of 63°N, piling up around the islands and backing into the fjords. I assumed that was mostly calving from local glaciers and northern ice coming down through the Denmark Strait. Never much ice off the west coast of Greenland.

Reply to  RACookPE1978
December 30, 2014 8:50 am

@RACookePE, I am not sure I understand what point you are trying to make. The GRACE data clearly agrees that there is accumulating mass on the northern inland masses. But due to the cold dry air accumulation rates are slow inland, and averaged overall that accumulation can be overwhelmed temporarily by coastal calving and basal melt. The widely trumpeted reports of Greenland’s shrinking mass comes from GRACE data that finds most of the mass is being lost along the coast, concentrated along the southeast where the full force of the warm intruding Atlantic currents are first felt.

Steve Thayer
December 29, 2014 11:51 pm

Interestingly the NASA page for GRACE for Greenland ice mass data only has data up to July of 2013. And they show -258 Giga tons per year loss rate as the summary for that data. The GRACE data has been showing a fairly consistently increasing Greenland ice mass loss rate over the last ten years, this most recent data is really shocking in that sense. I wonder what they will say the mass loss rate is after updating the data to include 2014. They’ll probably just average in this year’s data with the past 10 years and say the mass loss is still over 200 Giga tons per year.

David A
Reply to  Steve Thayer
December 30, 2014 2:52 am

I did not know GRACE had been operating for ten years?

Reply to  David A
December 30, 2014 8:54 am

Launched in spring 2002

The Ghost Of Big Jim Cooley (even more ghostly at this time of year)
December 30, 2014 12:03 am

If we see an Arctic sea ice recovery then I shall wet myself with excitement – and wait for all the back-peddling to come from the truly rotten Guardian, the mess that is the BBC (its ‘journalists’), and the green ‘we-are-all-going-to-die’ brigade. It will even be better than global cooling – as the Arctic sea ice loss is the poster child of the AGW movement, and there will just be no ignoring it.

The Ghost Of Big Jim Cooley (even more ghostly at this time of year)
Reply to  Jimbo
December 30, 2014 2:36 am
RH

I think you underestimate their flexibility. We are doomed unless we adopt the teachings of Marx.

December 30, 2014 12:13 am

Will Greenland Begin Accumulating Ice in 2015 and Beyond?</blockquote
This is a testable prediction.
Let's wait and see.

Reply to  MCourtney
December 30, 2014 12:17 am

Typo. Bother. Fingers are cold.
Still I predict a warming regional climate for the next 8 months.

Mac the Knife
December 30, 2014 12:23 am

An interesting and informative article – Thank You Dr. Steele!

stevek
December 30, 2014 2:42 am

I have a question for Dr. Steele or any chemists out there. Is it cheap to due a partial desalination of ocean water ? I’m not talking anywhere near full. For arguments sake is it cheap to remove only 1% of the salt as compared to 99%?
Reason I ask is if we can remove a little bit of ocean salt, would this not lead to more ice, thus more albedo and cooling of earth ?
Not I global warming is natural but the above is for interest only.

garymount
Reply to  stevek
December 30, 2014 2:59 am

Where would you store all of that salt?

garymount
Reply to  garymount
December 30, 2014 3:04 am

If we could increase the population of the earth by say an extra 4 billion people, all of those extra water vessels could counter the rise in sea level. Note, I haven’t calculated how much volume of water that would be.

Reply to  garymount
December 30, 2014 6:19 am

If one assumes that the average human weighs 62 kg and the average water content by weight is at least 50 percent, then the ~80 million humans added to the global population this year will retain roughly 2,480,000,000 additional liters of water during their adult lifetimes.

Reply to  garymount
December 30, 2014 9:11 am

Salt is “bad” for you so I’m sure there will soon be even more government regulations. Then it will be, following evil CO2, listed as a “pollutant” and then it will be illegal to store it… but until that time I think Al Gore’s mansions would be a good start or we could fill up all those salt mines we’ve been digging up for the last 3,000 to 5,000 years.

Mick
Reply to  garymount
January 8, 2015 2:32 pm

CO2 is Carbon so NaCl is Chlorine. Deadly stuff

AnonyMoose
Reply to  stevek
December 30, 2014 8:08 am

No, it is not cheap to desalinate. If it were, there would be more desalination plants producing fresh water in the many places where water is needed.
The cheapest way to remove salt from the ocean is to buy a large area of land, fill it with sea water, then let the water evaporate. Scrape up the salt. Repeat. But for removing 1% of salt from the ocean, it is not cheap because there is so much ocean.

stevek
Reply to  AnonyMoose
December 30, 2014 2:56 pm

By my calculations it will only take about 36 million years to cycle through all ocean water if we had a 100km by 100km basin that could evaporate 1cm depth of water per day.

Editor
December 30, 2014 3:36 am

The correlation between warm/cold phases in the Eastern Arctic and the AMO are clear.
http://notalotofpeopleknowthat.wordpress.com/2014/08/31/arctic-ice-and-the-amo/
The AMO will turn down in the next few years, and we will then be in for 30yrs of increased sea ice and much lower temperatures in Greenland.

Reply to  Paul Homewood
December 30, 2014 11:03 am

Paul your August 2014 article dove tails nicely here (sorry I missed it before). I would encourage everyone to read it http://notalotofpeopleknowthat.wordpress.com/2014/08/31/arctic-ice-and-the-amo/ The Transport Index and how transport is affected by the NAO and changes in the Atlantic gyres shows how they are all related to the AMO.

phlogiston
December 30, 2014 4:00 am

Thanks Jim – a magisterial analysis of the Greenland ice outlook.
Interesting times indeed. I have long suspected that a key component of the AMO is oscillation in the strength of the north Atlantic drift carrying warm water toward the Arctic and Barents sea. Interesting how it switches between Barents and Greenland.

rah
December 30, 2014 4:06 am

Man it seems to me that according to http://arctic.atmos.uiuc.edu/cryosphere/ that the sea ice around Greenland is doing just fine and already on a path of increase. As for the increase in calving from the glaciers it seems that geothermal activity has a whole lot to do with it. Anyway here is some fantastic footage of the largest calving even captured on video so far: https://www.youtube.com/embed/hC3VTgIPoGU?rel=0

Khwarizmi
December 30, 2014 6:27 am

If Antarctica and Greenland were melting and contributing to sea level rise, the weight of the melted ice would be redistributed relatively evenly around the globe from its isolated position in polar regions. As a consequence, the rotation rate of the Earth should decrease to conserve angular momentum, leading to an incremental persistent increase in the length of day (LOD).
But the trend in LOD has been negative since around 1978.
http://lh4.googleusercontent.com/-RpGKtg7JL3Y/VKKgTdkIcqI/AAAAAAAAAk4/bEwK-gyG8ug/s800/LOD-BULA_FinalsAllIAU2000A.png
“It is interesting to note that the present overall trend of LOD shown in this figure is decreasing, which is the reverse of secular increase of LOD due to tidal dissipation. This is ascribed to certain geophysical processes in the Earth’s core and mantle, such as geodynamo. Recent fast retreat of glaciers might be related as well.”
Earth Rotation Basic Theory and Features, Sung-Ho Na, p.20
Actually, the fast retreat of glaciers should increase the length of day, since their weight as liquid would be redistributed relatively evenly, with most of the weight shifting to lower latitudes, as with the hypothetical melting of Antarctica and Greenland. The result would be similar to a figure skater extending her arms during a pirouette to slow her rate of spin.
But the opposite seems to be happening.
Perhaps Antarctica has been putting on weight for the last 30 years?

Hugh
Reply to  Khwarizmi
December 30, 2014 11:05 am

” their weight as liquid would be redistributed”
Right, but assuming the Earth is a ball of molten rock, it will change shape under moving water, causing a minor compensating change. Which dominates? Sung-Ho Na sounds like an expert. For me this is faaar too difficult problem.

Barry
December 30, 2014 7:22 am

Climate change is a long-term trend, and climate variability imposes cycles on top of that trend. Just because the cycles are identified and explained does not mean there isn’t an underlying trend.

Reply to  Barry
December 30, 2014 8:16 am

Indeed climate change is a long term trend so what is the most informative time frame? Is there an underlying 5 thousand year cooling trend punctuated by ~1000 year warm spikes, of which the recent spike is just another manifestation? Scandinavian tree ring data supports the interpretation. The rapid Arctic warming in the 20s and 40s, followed by cooling in the 60s and 70s suggest that the most likely framework is an underlying cooling trend punctuated with warm spikes during periods of high solar irradiance.

rah
Reply to  jim Steele
December 30, 2014 8:33 am

And we are now in cycle 24 with solar activity generally trending down since cycle 21. http://solarscience.msfc.nasa.gov/images/Zurich_Color_Small.jpg and if predictions are correct cycle 24 will be the least active since cycle 14. I wonder what cycle 25 will bring?

mpainter
Reply to  Barry
December 30, 2014 11:23 am

Barry,
For underlying trend, see temperature record for the Holocene as per d18O.
Or do you say that your view does not go back that far?
As for me, I prefer warming to cooling. I say let’s stop the stepdown into another ice age.
From any perspective, atmospheric CO2 is entirely beneficial.

December 30, 2014 8:33 am

“With all things considered, the evidence strongly suggests we will soon witness a similar natural cycle and a rebound in the Greenland’s ice.”
how about a real prediction?
instead we get
“suggests”
“soon”
“similar”
“rebound”
words that can’t be measured or falsified.

rah
Reply to  Steven Mosher
December 30, 2014 9:08 am

Because they just don’t know but would like us to believe they do?

Reply to  Steven Mosher
December 30, 2014 9:19 am

@Steven Mosher I don’t understand your snakiness. The prediction is clear! Based on past natural cycles i believe we will see Greenland begin a trend of accumulating ice mass. I say the data “suggests” not to avoid our ability to verify or falsify. Anyone studying complex phenomena understands there is no certainty and the evidence can only “suggest” a future scenario that can indeed be tested. I say “soon” because I have no way of telling how each glacier will adjust on a month to month basis, or how to predict year to year changes in intruding Atlantic water. I can only point to the longer trend and past cycles. My title “suggests” that I believe we could see an increasing trend as “soon” as 2015. That prediction may fail to be verified in 2015, but the next 5 to 10 years will provide measure for you to falsify or verify. And that time will come much sooner than the predictions of an ice free Arctic in 2030 that CO2 warmists have trumpeted and dressed-up with unsupported certainty.

Reply to  jim Steele
December 30, 2014 9:21 am

snakiness should read snarkiness but was auto corrected

Reply to  jim Steele
December 30, 2014 11:36 am

It’s probably a good thing Ira Gershwin wrote before the days of auto correct.
You say “he’s snake-y”; I say “he’s snarky”.
He says “We’ll bake-y!”; I say “Malarky!”.
This warming they’re claiming,
our Climate is maiming,
and we’re not allowed to scoff.
… Let’s call the whole thing off.

Mac the Knife
Reply to  jim Steele
January 1, 2015 12:37 am

@Steven Mosher I don’t understand your snakiness.
I do believe the auto correct ‘got it right’.

James Strom
Reply to  Steven Mosher
December 30, 2014 10:19 am

This is probably a minority view here, but when the weather guys say that there is a 40% chance of rain tomorrow, they are making a real prediction. Likewise, when they say rain is “probable” or even that there is a “chance of rain”. They are using an ordinary language formulation of a probabilistic statement. Falsification is another matter. In weather you can compare the performance of a large set of predictions with actual outcomes and thus “confirm” or “falsify” a forecaster’s overall work, or the theory behind it. With climate we are often only interested in one prediction by a particular practitioner. These vague predictions are still predictions, but the process of evaluation has to be worked out. You could say that the whole messy discussion constitutes an effort to figure out how to evaluate climate forecasts. In Steele’s case he does say “strongly suggests”, so the failure of Greenland’s ice to rebound would count against him. If you accumulate a large number of his forecasts you would be in a position to verify/falsify his work.

provoter
Reply to  Steven Mosher
December 30, 2014 10:38 am

Wrong.
Gosh, that was easy – thanks Steven Mosher! From now on, I think I’ll add to conversations just like you do – so much easier on the fingers AND the brain.

provoter
Reply to  provoter
December 30, 2014 10:42 am

Doh! Stupid nested threads ;^>
The “Wrong” comment is meant to be directed at Steven Mosher’s fabulously well developed and wholly constructive argument above.

Jimbo
Reply to  provoter
December 30, 2014 11:30 am

Wrong.

Jimbo
Reply to  Steven Mosher
December 30, 2014 11:27 am

Mosher obviously fails to criticize the words “suggests” “soon” “similar” “rebound” used in climate papers.
I suspect Mosher is hatching a cunning plan to defend the overuse of caveats in Climastrology papers. What do you say Mosh?

[See original PDFs – via Google Scholar snippets]
…..Comparing the magnitudes and directions of these two factors suggests that climate change
is more likely than land-use change to be the cause of expansion….
http://www.nature.com/nature/journal/v421/n6918/abs/nature01286.html
————–
…habitats during the past 30 years, it is likely that the beetle will soon overcome the….
http://digitalcommons.usu.edu/barkbeetles/195/
————–
Similar patterns exist for lowland compared with highland birds in the tropics 43 . Most of these
studies are local, with high variability of individual species’ population dynamics….
http://www.nature.com/nature/journal/v421/n6918/abs/nature01286.html
————–
…climate change will lead to alternate ecosystem states or persistent instability (60) (Fig. 4B), or whether system states can rebound from abiotic…
http://www.sciencemag.org/content/325/5946/1355.short

Mac the Knife
Reply to  Jimbo
January 1, 2015 12:40 am

Got it in ‘one’, Jimbo!

Jimbo
Reply to  Steven Mosher
December 30, 2014 11:40 am

I PREDICT that Greenland WILL begin a trend of accumulating ice in 2015 up to at least 2040.
If I fail I will acknowledge my failure and will not defend it. Unlike the Arctic sea ice / wave ‘expert’ Professor Peter Wadhams who predicted that the Arctic will be ‘ice-free’ no later than 2016. Then he changed it to 2020.

Matthew R Marler
Reply to  Steven Mosher
December 30, 2014 12:04 pm

Steven Mosher: how about a real prediction?
instead we get
“suggests”
“soon”
“similar”
“rebound”
words that can’t be measured or falsified.

Not a problem. There were lots of propositions in the development of the “suggestion”. If the ice evolves as “suggested”, those propositions acquire credibility. If the ice does not evolve as “suggested”, at least some of them lose credibility. It’s the same as with all the “scenarios” of warming that the global warming alarmists try to claim are not real “predictions” on the occasions when the climate follows a different “scenario”; once written, the “scenarios”, “expectations”, “suggestions”, etc. are treated by the scientific world as propositions subject to disconfirmation dependent on subsequent events.

David A
Reply to  Steven Mosher
December 30, 2014 2:21 pm

Mosher you are getting ill. “strongly suggests” in a blog post is, all by itself far better then the maybe, could, might, found commonly in peer reviewed climate articles. In addition there is no demand for an increase in tax on individuals and corporations based on ifs, ands, and buts.
BTW, when, instead of a sad attempt to justify the entire surface record, will you explain just the Iceland adjustments to one station?

sceptic56109
December 30, 2014 10:16 am

In 1945, an Allied airfield in Greenland was abandoned and the planes were subsequently covered by many feet of ice. Sometime in the early 2000’s at least one of these aircraft was recovered by drilling a shaft through the ice and hauling the plane to the surface piece by piece. Does anyone know if the entire airfield has been exposed since because of all the recent warming in the Arctic?
Also, 20 private yachts got stuck in the Northwest Passage in 2013 because all the sea ice was supposed to be disappearing. I wonder if those yachts are still there, I have not heard about them being freed. Does anyone have an update?
Thanks

Reply to  sceptic56109
December 30, 2014 11:48 am

I think you’re thinking of various forced landings on Greenland, such as Glacier Girl. The entire squadron (8 planes) had to make a forced landing in 1942 and was abandoned, although all crew members survived and were rescued.
IIRC, most of the planes were too badly damaged by the weight of covering ice to be recovered and Glacier Girl had to be taken out in pieces.
I hadn’t heard about an entire airfield being abandoned; I would think any serviceable aircraft would have been flown out at the time.

Reply to  sceptic56109
December 30, 2014 5:19 pm

Sceptic,
It wasn’t an airfield … It was abandoned planes after forced/crash landings.
What I have always found very curious is the depth of cover of the ice over the planes. The “Lost Squadron” was covered by an average of 5 feet per year (268 feet deep … one reason why it took so long to find them). A much smaller plane nearer the coast was found at a depth of 38 feet (not much in comparison but it is +38 feet of ice over the 70 years, and it is not “…we found the plane because of the massive loss of ice due to global warming…”).
Without the global warming and the accompanying loss of ice they would have had to dig another 500 feet down to find the planes … right or wrong?
“Six American fighter planes and two bombers that crash-landed in Greenland in World War II have been found 46 years later buried under 260 feet of ice, searchers said today” (NY Times, 1988).
“At 38 feet, the team saw black cables consistent with wiring used in World War II-era planes like the Duck” (NY Times, 2013)

Genghis
Reply to  DonM
December 31, 2014 3:30 pm

What is happening is that the glacier flow is equal to the accumulation so that the depth stays the same. The planes are moving laterally with the flow.

December 30, 2014 11:20 am

“That LIA advance correlates with 1) lower solar flux, 2) decreased inflows of warm Atlantic water, and 3) a more persistent negative North Atlantic Oscillation.”
I don’t believe it. Increased negative NAO should increase poleward ocean transport.
“Curry (2001) created a Transport Index illustrating the correlation between the pole-ward transport of warm tropical water and the North Atlantic Oscillation. As seen in their illustration, there was a rapid increase in the pole-ward transport during the 80s and 90s when the NAO was in an increasingly positive phase.”
That’s not what I am seeing here:
http://bobtisdale.files.wordpress.com/2012/10/4-northern-no-atl.png

Reply to  Ulric Lyons
December 30, 2014 11:29 am

The AMO exhibits a pattern of running in phase with solar cycles in its cold mode, and out of phase with solar cycles in its warm mode. In the current warm mode, a brief cooling of the AMO/Arctic/Greenland around the maximum of solar cycle 24 due to a temporary increase in positive NAO. I would expect some of the most negative NAO of this solar minimum trough the next decade, and a strong renewed warming of the AMO/Arctic/Greenland:
http://www.woodfortrees.org/plot/esrl-amo/from:1880/mean:13/plot/sidc-ssn/from:1880/normalise

Reply to  Ulric Lyons
December 30, 2014 11:48 am

At least as far as 1880, this GISP proxy data moves inversely to CET. Cold periods on CET, the coldest part of the Maunder Minimum in the1690’s, the coldest part of the Dalton Minimum 1807-1817, and the equally cold 1836-1845, all show as warmer on GISP. While from the e.g. the 1690’s to the very warm 1730’s on CET, is cooling all the way on GISP. And the cold dip at ~1686 on GISP is around the very warmest point through Maunder on CET, with the previous cold dip in GISP being at a warm few years around the time of the great fire of London:
http://snag.gy/FdXju.jpg

Reply to  Ulric Lyons
December 30, 2014 11:49 am
Reply to  Ulric Lyons
December 30, 2014 12:05 pm

@ Ulrich, First you are comparing transport with ocean heat content. Nonetheless there would be a correlation. Second If you draw a second trend line starting anytime in the 1980s, I see a strong warming trend that lasts through the early 2000s, followed by a 10 years decline consistent with the recent decade of cooling waters in the Arctic estimated by Heimbach and Wunbsch 2014 http://landscapesandcycles.net/image/92559374.png
The rapid heat increase in the mid 90s, is in agreement with the contraction of the subpolar gyre and increased poleward transport during the downward trend of the NAO. The decreasing heat content since this past decade is consistent with the “mature phase” of the negative NAO.
So by what mechanism do suggest a negative NAO increases the poleward transport of warm water?

Reply to  jim Steele
December 30, 2014 12:33 pm

“Second If you draw a second trend line starting anytime in the 1980s, I see a strong warming trend that lasts through the early 2000s,”
I agree with Bob’ trend line, which shows continued cooling till 1995, as does Arctic Ocean UAH LT:
http://snag.gy/mfOI7.jpg

Reply to  jim Steele
December 30, 2014 12:45 pm

Ulric, I do not disagree with Bob’s trend line, but the 1980s represent an inflection point and therefore the two trends are not exclusive. To argue over which trends is “correct” is unproductive and will only cause us to talk past each other. It would be more productive to analyze the cause of the inflection.
I have asked you to elucidate your mechanism that would cause more tropical water to be pushed poleward during the negative NAO or the LIA. Once done we can compare that with the mechanism I outlined above and proceed from there.
Do you also disagree that there was less poleward transport during the LIA? Several studies indicate that to be true i.e. Lund 2006 Gulf Stream density structure and transport during the past millennium

Reply to  jim Steele
December 30, 2014 1:02 pm

“The decreasing heat content since this past decade is consistent with the “mature phase” of the negative NAO.”
Given a sharp increase in negative NAO even over the next few years, that trend could turn around to become positive fairly rapidly. I like to look at the detail rather than trends before I draw too many conclusions. Looking at Bob’s graph above, the greatest cooling in the last ten years is roughly mid 2006 to mid 2009, the AO has a general positive bias through that stretch, that may well be why.
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/month.ao.gif

Reply to  jim Steele
December 30, 2014 1:14 pm

“Do you also disagree that there was less poleward transport during the LIA?”
As I showed above, there are warm spikes in GISP at the coldest parts of Maunder and Dalton. And I am expecting the coldest part of this solar minimum for mid latitude land regions to be from 2015-2024.
“I have asked you to elucidate your mechanism that would cause more tropical water to be pushed poleward during the negative NAO or the LIA.”
If it’s the gyres then its the gyres. What is in debate is the sign of correlation, particularly Curry 2001.

Reply to  jim Steele
December 30, 2014 1:47 pm

Ulrich It appears you have not analyzed more than your statistical correlations and therefore you will not provide a mechanism. So now we must simply agree to disagree. Here’s where we agree and disagree:
You said “I would expect some of the most negative NAO of this solar minimum trough the next decade, and a strong renewed warming of the AMO/Arctic/Greenland:”
1. I agree that the next decade will be a stronger solar minimum and a more negative NAO
2. I disagree that we will witness warming for the AMO/Arctic/Greenland. The solar minimum suggests cooler tropical waters and a spin down of the subtropical and thus less pole-ward transport of warm water. Parts of Greenland may show anomalous warming due to the location of pressure systems and the requent foehn storms, but overall the glaciers will grow.
I assume because you hypothesizing renewed warming, you are implying glaciers will retreat and Greenland will continue to lose ice mass. Yes?
Hopefully WUWT will be even more popular over the next decade, and we can discuss how the universe either confirmed or falsified our hypotheses, or perhaps simply revealed greater complexities that we overlooked.

Reply to  jim Steele
December 30, 2014 2:24 pm

“The solar minimum suggests cooler tropical waters and a spin down of the subtropical and thus less pole-ward transport of warm water.”
Given that the coldest years of the Dalton Minimum (1807-1817) likely had five El Nino episodes, and that El Nino episodes act as a negative feedback to weak solar conditions, I can’t see that happening in a hurry. Poleward ocean transport into the Arctic should increase. But would the supply for the increased poleward transport start to cool with much reduced La Nina recharging of ocean heat content? By looking at particularly the very warm spike in GISP around 1350-1150 BC, I doubt it.

Reply to  jim Steele
December 30, 2014 2:30 pm

“I assume because you hypothesizing renewed warming, you are implying glaciers will retreat and Greenland will continue to lose ice mass. Yes?”
With increased poleward ocean transport, of course, And greatly reduced Arctic sea ice extent again too. I know how to forecast which summer months will see the strongest negative NAO and greatest sea ice loss through the whole period if you are interested.

Reply to  Ulric Lyons
December 30, 2014 12:29 pm

Because pressure systems always drive warm northward on one side and drive cold air southward on the other side, we should expect a ‘seesaw’ effect when pressure systems become entrenched. That is a weather pattern embedded within a climate trend. The Greenland/European seesaw has been well documented. Currently Greenland has experienced surface warming while Europe experiences more bitter winters. Greenland’s warming along the coast is due to pressure systems driving more warm and relatively moist air northward, which will increase snow accumulation in some places and decrease it in others. Often the east and west coasts of Greenland are out of phase.
However that seesaw effect does not appear to drive changes in coastal glaciers. While the loss of ice came to a standstill this pst year NOAA reported “Slightly negative (-0.7) North Atlantic Oscillation (NAO) conditions in summer 2014 promoted abnormal anticyclonic conditions over southwest and northwest Greenland; these favored northward advection of warm air along its western margin as far as the northern regions of the ice sheet (see Fig. 1.3d in the essay on Air Temperature). Further, the anticyclonic conditions reduced summer precipitation (snowfall) over south Greenland. The combination of southerly air flow and lower precipitation contributed to the melting, mass balance and albedo observations reported above.”

Reply to  jim Steele
December 30, 2014 7:22 pm

There has been a rather entrenched flow pattern in the jet stream since March 2013 that has favoured warmer in NW Europe and colder in Greenland anyway, driven by the very warm NE Pacific SST’s. May and June 2014 had negative NAO, but the UK didn’t see cooler conditions from that. The only negative NAO that had an impact in the UK this summer was in August. You can see the Arctic ice extent reduce around a week or so after it turned cooler in the UK:
http://arctic-roos.org/observations/satellite-data/sea-ice/observation_images/ssmi1_ice_ext.png

Matthew R Marler
December 30, 2014 11:42 am

With all things considered, the evidence strongly suggests we will soon witness a similar natural cycle and a rebound in the Greenland’s ice.
That’s almost a “prediction”. It will be interesting to observe whether the ice acts as suggested for it.

December 30, 2014 12:56 pm

Thanks, Dr. Steele. A very good article and video.
Yes, I think natural causes have more importance on Earth than man-made causes.
Not that I think we humans are not natural.
Hope more people will read your Lanscapes & Cycles book, it did a lot of good to me.

phlogiston
December 30, 2014 1:19 pm

What’s so strange
about climate change?
Climate means
Climate change
Ask Lorenz
Don’t know Ed?
Got no ‘ed?
Brain dead

December 30, 2014 2:18 pm

Won’t glaciers melt as long as the warming trend since the mid-1800’s continues … and isn’t it impossible to know in advance how long that warming will continue … except to look at ice core climate proxies and wild guess ‘hundreds of years”?
.
On the other hand, 2013 and 2014 could be the first two years of a new global cooling trend, and we could even be headed for another ice age. That frightens me because my home state of Michigan used to be under one to two miles of ice … and I don’t know how to ice skate.
.
But seriously folks, why is it that people love to get attention by predicting the future, and others actually listen to those predictions as if they are accurate? I just don’t get it.
.
Don’t we already get enough inaccurate predictions from the climate astrologers and their computer game models?

December 30, 2014 3:27 pm

Greene who says “why is it that people love to get attention by predicting the future
That is a bizarre question. So let me reply with 3 points.
1. The benefits of science comes from providing a theory or model of how stuff works. But anyone can make a model based on past correlations. A model’s value depends solely on how well it extrapolates into the future. Thus to test any model we must make predictions. If you do not understand that, you do not understand science.
2. I suspect in one way or another we have all made predictions and were right, but sadly we were right for all the wrong reasons, and were mislead later on. So it is important to describe the mechanisms and chain of causation that will lead to the predicted results. I predicted increased glacier mass on Greenland driven by a reduction in the poleward flow of warm Atlantic water. To test my model of how climate affects Greenland’s glaciers, the chain of causation must also be tested.
3. I indeed want to call attention to models that focus on the redistribution of ocean heat, and natural ocean oscillations. The CO2 crowd argues the changes in the cryosphere are due to rising CO2, but there are other explanations that correlate better with observed trends. Those alternative explanations make different predictions and allow us determine which models more accurately capture reality. So Richard I do not understand why you try to imply that making a prediction is some kind of personal attempt to get attention. Scientists alway makes predictions, that then must be tested, and we know those predictions may fail. Making predictions make scientists more vulnerable to future criticisms if wrong, or if not well thought out, so predictions are not made lightly.

Crispin in Waterloo
Reply to  jim Steele
December 30, 2014 5:04 pm

Jim, you could take this tack:
A formula for calculating the deflection of a beam when loaded, something used millions of times a day, is a model. It predicts the deformation of the beam based on the material properties and the load, and how it is positioned on the beam. Most people do not view the formula as a ‘model’ but it is. It predicts future performance.
Having a complicated model does not mean it cannot be written down as a formula with thousands of variables and constants. That is what a computer programme does.
If engineers were forced to use formulas that gave really wrong answers, we would not trust them to design bridges because they would fall down randomly, or all fall down within an unacceptably short time span, or waste vast resources on bridges that were ridiculously strong.
It seems to me climate modelers have managed to convince the general public, through omission and Grubering, that a model is fundamentally different from, say, a store cash register that calculates correct change using a validated formula involving subtraction.
A very complicated, a nested set of formulas and constants assembled into a Giant Formula that doesn’t work cannot tell us whether or not it is necessary to spend trillions of dollars to avoid burning carbon as an energy source. Common sense dictates that we can only spend when we have a validated model (perhaps just a little bit of money to validate the model – I’m flexible).
Tendered bill minus value of goods purchased equals change due. That is a model we can accept. The IPCC-adored climate models, not so much.

Phlogiston
Reply to  jim Steele
December 30, 2014 9:07 pm

If “Grubering” means openly and cynically taking advantage of the “ignorance” of the general public, then we need another word as well. We need a word for the practice of focusing attention on one single rising or falling segment of a natural oscillation and calling it a uniform change which will never end and will lead to catastrophe.
An example would be if someone living by the sea noticed the tide was rising and ran around the town shouting hysterically “O my God it’s a flood we’re all gonna die!”
Thus perhaps the term “TROMGIF” could be used to describe this bizarre practice arising from mental illness or attention-seeking, or both. It stands for “Tide – Rising – O – My – God – It’s a – Flood”.

GregK
December 31, 2014 12:52 am

Re Opluso’s calculation..
If one assumes that the average human weighs 62 kg and the average water content by weight is at least 50 percent, then the ~80 million humans added to the global population this year will retain roughly 2,480,000,000 additional liters of water during their adult lifetimes.
That’s 2.48 cubic kilometres
World’s oceans have a volume of 1,335,000,000 cubic kilometres
[ref http://www.ngdc.noaa.gov/mgg/global/etopo1_ocean_volumes.html%5D
We are going to have to add a lot of people to lower sea levels even a smidgen.

Venkatachalam Muthusamy
December 31, 2014 6:35 am

Attention Mr.Modi, Global leaders and UNFCCC: To conserve about 40% of fuel & thereby reduce carbon emissions, to control climate change and global warming, to prevent road crash deaths and save millions of people from pollution related diseases and to reduce 80% of traffic jams, to uplift the downtrodden and reduce economic inequalities etc. for the first time in the world, I POSSESS A WIPO APPROVED, NO-NONSENCE MIRACLE INVENTION. But, is there anybody in India and the world who can help me to dedicate this PANACEA to humankind? Please Mail to: *vthoorun.rcrv@gmail.com *

Sceptical lefty
December 31, 2014 7:01 pm

No-one has yet satisfactorily demonstrated a predictable cause for climate fluctuations. Even if we accumulate several thousand years’ worth of useful observations, we are still just curve-fitting until we understand these phenomena. For all anyone knows, the melting of Greenland’s ice could accelerate next year. If enough people make enough predictions someone is bound to ‘get it right’ and gain a reputation as a prophet.
One thing I will note: if the Greenland melt accelerates, the CAGW lobby will emerge reinvigorated to trumpet our imminent doom — unless we do as they say. They still won’t understand anything, but they will attract more followers.

January 1, 2015 8:10 am

Sceptical lefty
I agree. Our attempt to understand any phenomena begins with simple curve fitting and theories and models to explain that curve fitting. Several hypotheses are typically offered and linked to mechanisms that could possibly explain the observed relationships. However again the trick is to demonstrate how well those hypotheses extrapolate into the future. I often told my students we learn more from being wrong than right. We can be right for the wrong reasons, but failed hypotheses tell us what is not important. So I encouraged students and everyone to make predictions and let reality winnow out our illusions.

January 1, 2015 9:52 am

“Statistical studies have debated the correlation between retreating Arctic ice and the negative NAO because it generates a confounding short term warming trend that is contradicted by the longer cooling trend suggested for the LIA as well as observed during the 1960s and 70s.”
The 1970’s saw an increase in positive NAO and the associated increase in La Nina episodes. It also saw the AMO get to its coldest in its last cold mode, and an increase in Arctic sea ice extent.
Despite an apparent general cooling through the Maunder Minimum in GISP, the coldest years in CET in Maunder (1690’s), Dalton (1807-1817), and the equally cold 1836-1845, all register as warmer periods on the GISP proxy. The most rapid rise on CET is from the 1690’s to 1730, GISP goes in completely the opposite direction. Personally I would take the inter-annual noise more seriously than the apparent cooling trend of GISP through Maunder, because it is totally at odds with the very warm 1350-1150 BC in GISP, which had a very marked increase in El Nino, and much cold in the mid latitudes.
http://snag.gy/FdXju.jpg

don penman
January 1, 2015 9:53 am

I think that everyone is aware that a hypotheses may be shown to be false even if it seems to fit the data that we have but I am not going to allow the changing of past data to alter my view of reality,it is important that we keep looking forward if we are ever going to understand how the climate works.If we don’t know what the data was at a previous period then all we can say is that we don’t know but it is ok to speculate about the future because it can be shown to be wrong if it is wrong.