Danish researchers in Nature: '85 years of glacier growth and stability in East Antarctica'

Guess what: the more scientists look, the more grounds for the questioning of 'the Science™', their (sic) 'models™', and the 'Climate Crisis™' is warranted

Please accuse me of spreading whatever kind of ‘information’, widely understood, but do take note that there is a world of difference between that which is is believed or inferred as opposed to that which is (empirically) observed. That is, between a (more or less coherent) set of beliefs as opposed to what, from the seventeenth century onwards, became known as scientific enquiry.

As indicated by the header, today, we’ll enquire about this discrepancy in quite some detail as we’ll explore a new paper published in Nature Communications 15, Article number: 4466 (2024), entitled ‘Early aerial expedition photos reveal 85 years of glacier growth and stability in East Antarctica’—and it makes for fascinating reading.

Take note, further, that these findings are approved™ by ‘the Science™’, they are not my opinion (which you’ll find in the bottom lines), and—this will blow your mind, I suppose.

As always, for readability I omitted the references (check out the fully available piece following the link above for them); emphases mine.

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Early aerial expedition photos reveal 85 years of glacier growth and stability in East Antarctica

By Mads Dømgaard et al., Nature Communications 15, Art. no: 4466 (2024)

Abstract

During the last few decades, several sectors in Antarctica have transitioned from glacial mass balance equilibrium to mass loss. In order to determine if recent trends exceed the scale of natural variability, long-term observations are vital. Here we explore the earliest, large-scale, aerial image archive of Antarctica to provide a unique record of 21 outlet glaciers along the coastline of East Antarctica since the 1930s. In Lützow-Holm Bay, our results reveal constant ice surface elevations since the 1930s, and indications of a weakening of local land-fast sea-ice conditions. Along the coastline of Kemp and Mac Robertson, and Ingrid Christensen Coast, we observe a long-term moderate thickening of the glaciers since 1937 and 1960 with periodic thinning and decadal variability. In all regions, the long-term changes in ice thickness correspond with the trends in snowfall since 1940. Our results demonstrate that the stability and growth in ice elevations observed in terrestrial basins over the past few decades are part of a trend spanning at least a century, and highlight the importance of understanding long-term changes when interpreting current dynamics.

Introduction

The East Antarctic Ice Sheet (EAIS) contains more than 52 m of potential sea level equivalent (SLE). Recent observations indicate that the EAIS is more vulnerable than previously anticipated, and has made a considerable contribution to the continent-wide mass loss during the past decades. The losses have primarily occurred in some of the marine-based catchments in Wilkes Land, and are largely attributed to the intrusion of modified Circumpolar Deep Water (CDW) [i.e., there are certain areas that are ‘hot-spots’ (no pun intended) for ice losses belying the simplistic cries of ‘the Antarctic is melting’]. The terrestrial catchments, where the majority of the ice is grounded above sea level, have recently shown a mass gain caused by increased accumulation [i.e., it snowed in excess of melting], which has balanced some of the overall mass loss. Observational time series of glaciers in East Antarctica pre-dating the satellite era are rare and consequently not long enough to determine if recent trends are independent of natural fluctuations [and this is where it gets interesting, because the satellite era began in the late 1970s, hence all longer reconstructions of whatever are rife with data splice (not that the stuff documenting changes since isn’t due to multiple generations of different data collection machines)]…In Greenland and Svalbard, long-term observations from historical aerial images have been vital for determining the historical response of glaciers to climate change. However, in Antarctica, the scarcity of historical climate data makes climate reanalysis estimates before the 1970s largely uncertain, and observed trends cannot clearly be distinguished from natural variability.

Here, we rediscover and utilize the images from the earliest large-scale aerial photography campaign conducted on the Antarctic continent, allowing us to extend the era of observational records of glacier evolution back to the 1930s…On the Antarctic Peninsula, these observations show widespread near-frontal surface lowering and inland stability since 1960. On the other hand, historical observations of the Byrd Glacier over the past 40 years indicate a constant surface elevation, stable grounding line, and surface flow velocity [i.e., in the event such analysis has been carried out, the ice is either stable or building].

Here, we study 21 glaciers located in three regions along c. 2000 km of the EAIS, from Lützow-Holm Bay (38° East) to Ingrid Christensen Coast (79° East) (Fig. 1A). All glaciers are marine-terminating outlets of the EAIS, varying in width from 2 to 10 km, and with the fastest flow speeds reaching 2 km/yr. Some have large floating ice tongues, while others have their frontal position close to the grounding line. The glaciers are located in basins containing around 2.6 M km3 of ice (SLE 7.23 m), and the specific sub-regions studied (Fig. 1A) contain 0.42 M km3 of ice (SLE 1.15 m). In recent decades, these regions have maintained balance or gained mass, leading to advances in terminus and grounding line position, during a period of substantial mass loss and terminus retreats occurring at other sectors of the Antarctic Ice Sheet.

[Sources]

In late 1936, the Norwegian whaling entrepreneur Lars Christensen initiated his fifth and final expedition (Thorshavn IV) to Antarctica with the specific aim of capturing aerial images for producing the earliest detailed maps of the East Antarctic coastline…The expedition acquired 2200 photographs covering approx. 2000 km of the coastline from 82° to 20° East (Fig. 1A and Supplementary)…they were not published until 1946 due to the German occupation of Norway. Since then, the images have been stored at the Norwegian Polar Institute in Tromsø and largely forgotten. Luckily, the film has been kept at optimal conditions, giving us the best possible starting point for recreating the historical East Antarctic glacier conditions with modern digital technologies.

The images from the Norwegian 1936-37 expedition are unique, as they provide the earliest detailed view of a regional Antarctic coastline and allow historical reconstruction of glaciers in East Antarctica. The image archive poses considerable challenges for analysis due to its limited camera metadata, sparse flight line and camera position information. Consequently, a comprehensive manual image selection and geolocation process is essential prior to conducting any analysis (Methods) [look, this isn’t just feeding a super-computer with data]…we have successfully identified 128 images, with sufficient overlap, contrast and bedrock presence for ground control. The Norwegian 1936/37 imagery is combined with more recent historical aerial photographs (1956–1973) from Australian aerial campaigns (Fig. 1) and also with modern satellite data. This allows us to quantify changes on a decadal timescale throughout the 20th and 21st Century [reads like a well-done, careful study based on original documents + modelled data and cross-related to another set of photographs and satellite data: we need more such studies].

Results: Historical frontal retreat and constant long-term ice elevations in Lützow-Holm Bay

Despite large variations in size and characteristics, all six glaciers in Lützow-Holm Bay experienced a net retreat between 1937 and the 1980s [huhum, interesting—’the Science™’ spoke of an impending ‘ice age’ then, and many ‘modern’ data sets begin around 1980], when they reached an almost simultaneous minimum (Fig. 2) associated with a complete break-up of fast ice in the bay. Another smaller retreat phase occurred around the mid-2000s, with the exception of Shirase, and again during 2016-18…Since the retreat in the 1980s, all glaciers except Langhovde and Honnörbrygga have, at some point, advanced to a similar marginal position or even extended beyond their extent recorded in 1937…

Consequently, the absolute elevations have remained unchanged throughout the entire observation period from 1937 to 2020 (Fig. S23). Modern altimetry-based observations covering the years 2003 to 2021 confirm limited surface elevation changes along the Syowa Coast…except for Shirase Glacier, which exhibited thickening…

Regional frontal fluctuations and long-term ice thickening

Our observations show no regional long-term trend in the frontal positions of the studied glaciers in Kemp Land, Mac Robertson Land, and along Ingrid Christensen Coast between 1937 and 2022. The glaciers fluctuate between periods of frontal advances and retreats of varying distances (<0.1 km to 13.5 km) and intervals (3–50 years). Most noticeable is the 13.5 km advance of Mulebreen Glacier since the 1980s and the retreat of Jelbart Glacier, which is 3.5 km short of its 1937 marginal position…

Despite the long-term thickening of the glaciers in Kemp and Mac Robertson Land and along Ingrid Christensen Coast, our results reveal variations in the magnitude of the rates and periods of thinning. Specifically, Taylor and Utstikkar Glacier experienced thinning between 1956/1960 and 1973, Jelbart from 1937 to 1973, and Hoseason, Flatnes, and Hovde exhibited thinning during the past decade (Fig. 2) [no correlation with CO2 levels, it would seem?]. These findings suggest low magnitude decadal variability superimposed on a pattern of long-term thickening.

Our analysis of historical velocities of glaciers in Kemp and Mac Robertson Land reveal a pattern of constant flow velocities since the 1950s [ouch, CO2 doomsters] (Fig. 3). The historical velocities have an uncertainty range of 7.2 m/yr to 10 m/yr, and for Taylor, Jelbart, Hoseason and Utstikkar Glacier, the historical velocities fall within the range of modern satellite-derived velocities from 2006-2018, even when disregarding the 2006-2013 annual velocities with a high level of uncertainty.

Discussion

The absence of pronounced regional trends in frontal position in Kemp and Mac Robertson Land and along Ingrid Christensen Coast is in line with existing observations of basin-wide median frontal movement rates between 1974 and 2012. Historical observations of glacier terminus positions from other regions in East Antarctica reveal cyclic behavior with no overall trend from the 1950s to the late 1990s. Contrary, on the Antarctic Peninsula, the majority of glaciers have retreated since the 1950s with a suggested link to atmospheric warming [although one notes that the peninsula is farther north than the area studied]…our findings of a long-term frontal retreat at Honnorbrygga and Langhovde Glacier since 1937 does not coincide with any changes in the surface elevation of these glaciers (Fig. 2), suggesting that these floating ice tongues have provided limited buttressing on a decadal time-scale. Additionally, our results indicate that the land-fast sea-ice conditions controlling the frontal position of Langhovde and Honnörbrygga Glacier have become more susceptible to break up during the past 85 years. Notably, recent findings have pointed towards a possible link between these localized sea-ice breakups and the detection of Warm Deep Water (WDW) beneath Langhovde Glacier in 2018 [where would WDW come from—it doesn’t seem to be connected to atmospheric warming]

The terrestrial regions of the EAIS respond mainly to atmospheric forcing. Overall, there has been no significant trends in annual or seasonal mean air temperature in East Antarctica since the 1950s, and mean austral summer air temperature (December to February) from stations in all regions rarely exceeds 0 °C [!!!] (Fig. 4C). This suggests that surface melting have played a minimal role in the documented ice thickness changes overtime. However, at Davis station we do observe periods of above zero-degree temperatures during the 1970s and 2000s, which have caused intervals of increased ablation in this region near sea level.

While previous research on Antarctic snowfall found no statistically significant changes since the 1950s, recent studies utilizing compiled data on ice core records indicate increased Antarctic-wide snow accumulation during the past 200 years, with links to atmospheric warming, ozone depletion, and a positive shift in Southern Annular Mode (SAM) [all of which increases snowfall, right?]. Nevertheless, there are notable regional differences in accumulation in both sign and magnitude, and in East Antarctica the results are derived from only a few ice core records [a flashing warning light].

ERA5 reanalysis data suggest a consistent positive long-term trend in mean annual snowfall along the coastline of Kemp and Mac Robertson Land, and Ingrid Christensen Coast since the 1940s, whereas in Lützow-Holm Bay, snowfall has remained almost constant (Fig. 4B)…the trend in snowfall corresponds with the observed long-term historical changes in glacier elevations in each of the respective regions (Fig. 4). Observation-based atmospheric reanalysis data of Antarctica are questionable prior to the satellite era due to a lack of historical data, particularly concerning snowfall. The trend in snowfall since 1979 is nearly identical trends to that from 1940 for all regions (Fig. 4)…

Our historical observations of ice-thickness changes provide valuable insights into historical mass balance estimates of East Antarctica, as in situ records of mass balance are extremely few in Antarctica. Currently, the earliest ice-sheet wide mass balance estimates start in the late 1970s, and since then all the sub-regions examined in this study have exhibited either an overall mass gain or been relative unchanged [oh, look, no ice mass loss in Antarctica since the late 1970s: when was the last time you heard legacy media saying that?]. Given that our historical reconstructions extends beyond the era of reliable climate reconstruction, and considering the limited magnitude of the observed long-term changes and their localized spatial resolution, we are unable to further deduct the specific drivers of the observed changes. Regardless of potential climatic changes, our results indicate that the glacier in Kemp and Mac Robertson Land and along Ingrid Christensen Coast, have accumulated mass during the past 85 years which inevitably have mitigated parts of the more recent mass loss from the marine basins in East Antarctica and the West Antarctic Ice Sheet (WAIS). This positive accumulation trend and positive mass balance is anticipated to persist as snowfall is expected to increase over the entire EAIS in the next century, and ice sheet modeling studies project positive mass balance estimates in all three sub-regions across all future RCP scenarios.

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Bottom Lines

That’s quite…something, eh?

I have questions, quite a few now, and we’ll start with the last paragraph cited above:

If ‘positive accumulation trend and positive mass balance is anticipated to persist as snowfall is expected to increase over the entire EAIS in the next century’, what role would atmospheric CO2 emissions play in this?

More poignantly, if an ice age is characterised by arctic and antarctic ice caps, what do the results for the Antarctic mean for the Arctic?

Will we be seeing comparable trends—a ‘positive mass balance…as snowfall is expected to increase…in the next century’—in the North Pole area, too?

We note, in passing, the paucity of weather stations and available data in general with respect to both polar regions—and of those studies that are there, we see no changes or increases in ice mass:

'Observations show that Antarctic ice shelves gained 661 Gt of ice mass over the past decade'

Beyond the polar regions, we note that, e.g., the European Alps were ice-free some 5,500 years ago, as Andrea Fischer of the Austrian Academy of Sciences has published in Nature a few years ago (and nevermind the BS she spouts on public radio since):

Alps were Ice-Free around 3,350 Years Ago, According to the Peer-Reviewed Literature Published in 'Nature'

Further evidence—actually, a lot (see linked contents)—of human installations and artefacts above 2000m above sea level dating to some 500 (!) years ago—is provided by Norwegian archaeologists on a near-annual basis:

Where Once Glaciers Rested, Archaeologists Literally Stumble Across Artefacts

Finally, let’s all ponder the question: what does it mean for the future of humankind everywhere now that we’re looking at a century of increased snowfall in the Antarctic region?

Now, that’s the 64m dollar question—and I would personally dare a guess: the so-called ‘Little Ice Age’ (for a hilarious ‘discussion’, click here), with all the implications, from reduced crop yields to shorter growing seasons to increased geopolitical competition (coercion), it entailed. This is, incidentally, the period I specialise in researching, with European history providing tons of archival and other evidence.

That is, if we’re lucky.