Is there a Quasi-60 years ’ Oscillation of the Arctic Sea Ice Extent ?

A better understanding of the future climate pattern developments in the Arctic may only follow a better reconstruction of the past patterns of natural oscillations and the determination of the forcing and the resulting oscillations occurred in the climate parameters over different time scales. The proposed information for the past demonstrates the Walsh & Chapman reconstruction [1] claiming a flat sea ice 1870 to 1950 is too simple. The Arctic sea ice experienced a drastic reduction that was phased with warming temperatures 1923 to 1940. This reduction was followed by a sharp cooling and sea ice recovery. This permits us to also conclude that very likely the Arctic sea ice extent also has a quasi-60 years’ oscillation. The recognition of a quasi-60 year’s oscillation in the sea ice extent of the Arctic similar to the oscillation of the temperatures and the other climate indices may permit us to separate the natural from the anthropogenic forcing of the Arctic sea ice. The heliosphere and the Earth’s magnetosphere may have much stronger influence on the climate patterns on Earth including the Arctic sea ices than has been thought. Original Research Article Parker and Ollier; JGEESI, 2(2): 77-94, 2015; Article no.JGEESI.2015.009 78


INTRODUCTION
The recent article [2] suggests a link between the Greenland climate and solar activity on a millennial scale.Changes in solar activity have caused decadal-to millennial-scale fluctuations in both the modern and Holocene climates.While direct observational records of solar activity, such as sunspot numbers, exist for only the past few hundred years, solar variability for earlier periods is reconstructed from measurements of cosmogenic radio nuclides such as 10 Be and 14 C from ice cores and tree rings.Their highresolution 10 Be record from the ice core collected from central Greenland spans the time from 22,500 to 10,000 years ago.Using 14 C records to control climate-related influences on 10 Be deposition, [2] reconstruct centennial changes in solar activity to find that during the Last Glacial Maximum, solar minima correlate with more negative δ 18 O values of ice and are accompanied by increased snow accumulation and sea-salt input over central Greenland.Solar minima could have induced changes in the stratosphere that favour the development of high-pressure blocking systems located to the south of Greenland.The interesting conclusion of [2] is that the mechanism behind solar forcing of regional climate change may have been similar under both modern and Last Glacial Maximum climate conditions.It is therefore of paramount importance to understand to what extent the present sea ice evolution in the Arctic is at least partially a natural movement.
Here we present all the available observations and computational information:  recent (since 1979) satellite measurements of South and North pole sea ice extent and Global, South and North Pole surface air temperatures;  -reconstructions (computations) of the Global, South and North pole temperatures and North Pole sea ice extent since the end of the 1800s/beginning of the 1900s;  -scattered but consistent empirical information showing a shrinking of the Arctic sea ice in the first half of the 1900s followed by a sharp recovery.
In the discussion section, this information is then shown to support a coupling between Arctic sea ice extent and Arctic surface air temperature, and the existence of a quasi-60 years' oscillation of all the climate parameters for the Arctic as also evidenced in many pieces of literature.The work then shows the contradictions of the Arctic sea ice reconstruction [1] that like other reconstructions of temperatures and sea levels supporting the IPCC narrative, are not supported by observational evidence.The actual information for the past is mostly missed in the reconstructions, but what is available contradicts the parable of warming temperatures, rising seas and shrinking sea ice following the anthropogenic carbon dioxide emission since the end of the 1800s.Specifically the presented data are shown to be directly (measured sea ice extents) or indirectly (measured temperatures) inconsistent with the reconstruction [1].

AVAILABLE EXPERIMENTAL AND COMPUTATIONAL DATA
The climate-related parameters including temperatures, sea levels and sea ice are characterized by numerous oscillations with various periodicities.In addition to a longer term movement initiated about 1910, the temperature reconstructions since the 1800s show that the worldwide temperatures have oscillated with up to a quasi-60 year's multi-decadal periodicity [3,4].The existence of the quasi-60 years' climate periodicity is confirmed by several authors [3][4][5][6][7][8][9][10][11][12][13][14][15].The recent (since 1979) satellite air temperatures and sea ice extent measurements show consistency between ice shrinking or expanding and warming or cooling of the North or South Pole.The reduced sea ice extension for the Arctic is associated to a warming surface air temperature, as the increased sea ice extension for the Antarctic is associated with a cooling of the surface air temperatures.It is therefore likely that also the sea ice pattern in the Arctic could have experienced similar oscillation.

Global Temperature Reconstruction
Fig. 1 presents the global surface air temperatures reconstructed by the National Aeronautics and Space Administration (NASA) Goddard Institute for Space Studies (GISS) [16].The reconstructed GISS global temperature data since 1880, Figs. 1 a, b, are accompanied by the fitting of the data with a line and sines.The data are shown as monthly values plus the values detrended vs. the linear fitting.The warming trend is 0.0065°C/year.The GISS product is biased towards much larger than actual warming Despite the many adjustments of the GISS product to comply with climate model descriptions, the longer term warming phase started in 1910 with superimposed quasi year's oscillations.There is about the same warming between 1910 and 1940 as the warming between 1970 and 2000 and the flat temperature (or 'pause') between 1940 and 1970 is like the pause since 1998 [3,4].The data are downloaded from [16] and the analysis is provided here.

Global, Arctic & Antarctic Short Term Satellite Temperatures
The

Arctic & Antarctic Short Term Satellite Sea Ice Extents
The

Arctic Sea Ice Extent Reconstruction
The historical sea ice extension for the Northern Hemisphere is proposed in Fig. 8.The data are downloaded from [21] and analyzed here.The historical sea ice extent for the North Pole by [1] further updated to the year 2008, does not present any quasi-60 year's periodicity, and does not seem to follow the temperature of Fig. 2a.The sea ice cover is reducing since 1950, while it is increasing earlier.If the ice melting is proportional to the warming temperature, Fig. 2a and Fig. 8a cannot both be correct.In particular, the start of the ice melting is phased with cooling or not warming temperatures until 1980, and the previous warming period that produced the hot temperatures 1937 to 1943 very close to the present temperatures had no effect on the ice melting.It is unclear where [1] gathered the information needed to define the seasonal and yearly sea ice pattern for the time window 1870 to 1950, as surveys were very difficult to perform except during the summer months.This historical sea ice extension for the North Pole is generally accepted as the ice pattern for the Arctic [22].
The reconstruction [1] does not exhibit any quasi-60 years' oscillation while the temperatures have a strong quasi-60 years' signature.

Other Information Available for the Past Arctic Sea Ice
There is scattered but consistent information available for the Arctic sea ice that seems to confirm that a reduction and recovery of North Polar ice have occurred before, suggesting the latest Arctic pattern is at least partially a naturally recurring event.The Arctic climate variations are amplified by the specific mechanisms, the Arctic amplification [18], that make the Arctic, a sea surrounded by land, much more unstable than the Antarctic, a land surrounded by sea.This factor has to be properly accounted together with natural and possible anthropogenic for cings to understand the future Arctic climate evolutions.The reduction of sea ice extent 1922 to the end of the 1930s (during the second world war there was no measurement) is confirmed by the Dänische Meteorologische Institut (DMI) maps of the Arctic ices recently brought to the attention of the scientific community by [24].
Brunnur [25] presented a number of maps showing Arctic ice extend from 1893 to 1961 collected by DMI in "Nautisk Aarbog".Each year DMI have collected information on sea ice extend so that normally each of the months April, May, June, July and August ice extend was published.Lansner [25] ; Article no.JGEESI.2015.009analyzed the August data, where the ice coverage is not the minimum, because the September data were unavailable.Some of these maps (images from [25]) are reproduced in Fig. 9, and compared with the latest satellite images (from [21]) in Fig. 10 for years that

DISCUSSION OF A QUASI-60 YEARS' PERIODICITY IN THE ARCTIC SEA ICE
The data proposed in the previous paragraph suggest that there may be an oscillation of Arctic ice coverage but presently the reference work for the Arctic ice does not show this and indicates continuously decreasing ice coverage.Temperatures and sea ices are certainly coupled as shown by the satellite results, and if the Arctic temperatures oscillate, the Arctic sea ice should logically do the same, as confirmed by the scattered information for the first half of the 1900 from the Ifft's narrative [23] to the DMI maps.
The information available for the Arctic sea ice coverage is scattered and it is difficult to reconstruct a reliable pattern spanning even only the last 100 years.The reconstruction [1] proposes a sea ice extension about constant from 1870 to 1950s and then sharply decreasing, in the yearly values as well as the values in every season.Other information, such as the DMI maps, shows that during the summer months the The recent satellite measurements of sea ice and temperatures show consistency for the Arctic as well as the Antarctic.The DMI maps are consistent with the temperature trend.The reconstruction [1] is not consistent with this temperature trend.While the reconstruction [1] has no quasi-60 years' periodicity, the temperature reconstruction has a clear quasi-60 year periodicity, as the top temperatures of the 1940 and 2000 are very close.The DMI sea ice maps in the end of the 1930s are also very similar to the satellite sea ice maps end of the 1990s and suggest a similar quasi-60 year periodicity in the sea ice extent.A significant literature supports the existence of a quasi-60 years' oscillation in the Arctic sea ice similarly to the Arctic temperature further supporting the claim that the extended reconstruction [1] may be inaccurate, at least over the period 1880 to 1950.According to [27] the warming event in the first part of the 20 th century was a long lasting event commencing in the early 1920s and reaching its maximum some 20 years later.The following decades were much colder, although not as cold as in the early years of the last century, until the latest warming phase shifted of quasi-60 years.As noted by [28] and [29] the ongoing warming has reached in the 2000s the peak values of the 1940s.
Polyakov [30] used April through August ice observations in the Nordic Seas, Iceland, Greenland, Norwegian and Barents Seas, to construct time series of ice-edge position anomalies spanning the period 1750-2002.They found evidence of oscillations in ice cover with periods of about 60 to 80 years and 20 to 30 years, superimposed on a continuous negative trend.The persistent ice retreat started in the mid-1900s.
Venegas and Mysak [31] analyzed century-long records of sea ice concentration and sea level pressure pole ward of 40°N latitude.They evidenced many quasi-decadal and inter-decadal timescale fluctuations accounting for a large fraction (60-70%) of the natural climate variability in the Arctic.They identified climate signals with periods of 6-7 years, 9-10 years, 16-20 years, and 30-50 years.According to [27] a computational analysis of the spatial characteristics of the observed early century surface air temperature anomaly reveals the temperature variation was associated with similar sea ice variations.
Mörner [32] discusses how solar variability affects Earth climate not only through solar irradiance as generally considered, but predominantly through the interaction of the Solar Wind with the Earth's magnetosphere.The 60-years cycle recorded in solar activity and earth rotation affect the oceanic circulation, the temperatures, the sea level changes and the Arctic sea ice.As also evidenced by [33]  The flat trend is also inconsistent with temperature reconstructions which warming since the 1920s and a cooling before the latest prolonged warming not plausible that the strong warming 1945, not very different from the warming phase should have had no Arctic sea ice extent.
As the Arctic temperature oscillates 60 years' periodicity, then the Arctic should do the same, and as the Arctic sea ice has declined strongly in the recent past but it has also strongly recovered, some recovery will surely occur again in the future.

Fig. 1 .
Fig.1.Reconstructed global surface air temperatures since 1880.anomalies, whileb) are the values de months moving averages are superimposed.especially for what concerns the warming trend is questionable continuous adjustments of the computational procedure and of the supporting temperature records with often drastic changes of past temperatures suddenly introduced (see comparison of 2014 v3 with 2011 v2 as an example), n

Fig. 2 Fig. 1 .
Fig. 2 presents the reconstructed HadCRUT4 temperatures for the Arctic and Antarctic as proposed by [17].HadCRUT consists of monthly sea temperature records compiled by the Hadley Centre of the UK Met Office and land temperature records compiled by the Climate Research Unit (CRU) of the University of East Anglia, hence the acronym HadCRUT.Figs. 2 a, b present the mean annual surface air

Fig. 2 .Fig. 2 .
Fig. 2. Reconstructed Arctic and Antarctic surface air temperatures since 1900 (Arctic) 1957 (Antarctic respectively).a) are the Arctic and b images are from [17].The peak Arctic temperatures of 1940 2005-2010, suggesting a quasi-60 years' oscillation may also be measurements prior to 1920 are particularly unreliable In the article of 1922 THE CHANGING ARCTIC by Ifft [23] the effect of global warming on the Arctic climate was already evident.seems to be warming up.Reports from fishermen, seal hunters, and explorers who sail the seas about Spitzbergen and the eastern Arctic, all point to a radical change in climatic conditions, and hitherto un-heard temperatures in that part of the earth's surface

Fig. 2 .Fig. 3 .
Fig. 2. Reconstructed Arctic and Antarctic surface air temperatures since 1900 (Arctic) and the Antarctic temperature anomalies.The 1945 are close to the values of present in this pattern.The

Fig. 4 .Fig. 5 .
Fig. 4. Satellite temperatures of the South Pole since 1979.a)are the temperature anomalies, while b) are the values de-trended to the linear fitting line.Data are from [19].The 36 months moving averages are superimposed

Fig. 6 .Fig. 7 .
Fig. 6.Satellite sea ice extent North Pole since 1979.a) are the sea ice coverage anomalies, while b) are the values de-trended to the linear fitting line.Data are from [20].The shrinking of ice is consistent with the warming temperature of Fig. 3

TheFig. 8 .
Fig. 8. Extended Walsh & Chapman [1] North Pole sea ice extent, for every season and yearly.a)are the sea ice coverages, whileb) are the values de-trended vs. the linear fitting line.Data are downloaded from [21].This pattern of sea ice extent is inconsistent with the temperature pattern of Fig. 2.a.In particular, the very hot Arctic period 1940-1945 is claimed to have the largest sea ice coverages.The pattern is also inconsistent with the actual measurements of sea ice performed by the Dänische Meteorologische Institut (DMI), as shown in Fig. 9

Fig. 9 .b
Fig. 9. e,f: past DMI maps (from [24]) for August 1937 and August 1938.The sea ice has further considerably reduced.The sea ice was stable 1910 to 1923, then drastically reducing 1923 to 1940.During the Second World War there are unfortunately no measurements, but after the war the 1950 extension is similar to the 1910 values.Note that the DMI maps are only available during the summer months, as it was practically impossible to perform surveys during the winter months over most of the last century.These maps e, fclosely resemble the latest satellite maps for recent years, as shown in Fig. 10

2.2 Arctic & Antarctic Temperature Reconstructions
While the North Pole sea ice is shrinking over the short time period, the South Pole sea ice is increasing.Consistently, there is a warming for the North Pole and a cooling for the South Pole.
National Snow and Ice Data Center (NSIDC) sea ice extent by satellite [20], Figs. 6 and 7 respectively for the North and the South pole, show over the same period a reduction of the North Pole sea ice at a rate of -0.06016•10 6 sq.km/year, and an increase for the South pole sea ice of0.02737•10 6 sq.km/year.The trends are computed by linear fittings.