Archives par mot-clé : Ice

climate-debate

Antarctic Ice Is Increasing…Climate Models “No Longer Reflect Reality”

by Prof. F. Vahrenholt, May 13, 2025 in NoTricksZone 

If you look at the climate website of the Helmholtz Association with the ambitious name “Climate Facts” under Antarctica, you will read the following: “The important mainland ice of Antarctica is disappearing, and at an increasing rate”. According to the Helmholtz Association, this is of great significance for rising sea levels. And indeed, the rising sea level caused by the melting Antarctic ice is one of the central arguments of climate policy that has worried people.

This makes the result of a recently published study, according to which the picture has changed since 2021, all the more surprising: Antarctica’s continental ice is increasing again.

Chinese researchers from Tongji University led by Prof. Shen and Dr. Wang found that Antarctic ice masses have increased significantly since 2021. The data evaluated by NASA’s GRACE satellite showed an annual loss of 74 billion tons per year from 2002 to 2010. From 2011 to 2020, the amount even doubled. Now the ice has increased by around 108 billion tons year on year.

Source: Science China Press)

As the melting of the Antarctic glaciers contributed around 20% to sea level rise, a slowdown in the rise has been observed since 2021. Wouldn’t this good news be worth reporting on the news? Not so far.

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climate-debate

New Study: Antarctic Ice Sheet Surface Mass Balance Has Been Increasing Due To Recent Mass Gain

by K. Richard, May 05, 2025 in NoTricksZone 

The Surface Mass Balance (SMB) for the Antarctic Ice Sheet (AIS) has been remarkably stable since the 1970s.

However, according to the authors of a new study (a preprint soon to be published), “in recent years, the SMB has increased on the AIS, in particular for 2022, which mostly originates from mass gain on the EAIS.”

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better to know...?, climate-debate

Antarctica’s Astonishing Rebound: Ice Sheet Grows for the First Time in Decades

by SciTec, Apr 25 2025

The Antarctic Ice Sheet (AIS) plays a major role in global sea-level rise. Since March 2002, the GRACE (Gravity Recovery and Climate Experiment) mission and its successor, GRACE-FO (GRACE Follow-On), have provided valuable data to monitor changes in ice mass across the AIS.

Previous studies have consistently shown a long-term trend of mass loss, particularly in West Antarctica and the Antarctic Peninsula, while glaciers in East Antarctica appeared relatively stable. However, a recent study led by Dr. Wang and Prof. Shen at Tongji University has found a surprising shift: between 2021 and 2023, the AIS experienced a record-breaking increase in overall mass.

Antarctic Ice Sheet’s Mass Drama,From Accelerated Loss to Surprising Gain
Antarctic Ice Sheet mass change series (April 2002–December 2023) derived from GRACE/GRACE-FO satellite gravimetry. Ellipses highlight period-specific mass change rates, while the grey shadow indicates the data gap between missions. Credit: Science China Press

Notably, four major glaciers in the Wilkes Land–Queen Mary Land region of East Antarctica reversed their previous pattern of accelerated mass loss from 2011 to 2020 and instead showed significant mass gain during the 2021 to 2023 period.

Record-breaking mass gain over the Antarctic Ice Sheet

From 2002 to 2010, the AIS has experienced a mass loss with a change rate of –73.79±56.27 Gt/yr, which nearly doubled to –142.06±56.12 Gt/yr for the period 2011–2020. This accelerated mass loss was primarily related to intensified mass depletion in West Antarctica and the WL-QML region of East Antarctica. However, a significant reversal occurred thereafter, driven by anomalous precipitation accumulation, the AIS gained mass at a rate of 107.79±74.90 Gt/yr between 2021 and 2023.

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climate-debate

Antarctica Ice Growing Across Large Areas for at Least 85 Years, Aerial Photos Show

by C. Morrison, Mar 12, 2025 in WUWT

Sensational new discoveries arising from long-forgotten early aerial photographs indicate that ice has remained stable and even grown slightly since the 1930s over a 2,000 km stretch of East Antarctica. In a recent paper published in Nature Communications, researchers from the University of Copenhagen came to their conclusions by tracking glacial movement in an area with as much ice as the Greenland ice sheet. The findings are unlikely to feature in narrative-driven mainstream media. The silence will probably replicate the response to another recent paper that found the ice shelves surrounding Antarctica grew in overall size from 2009-2019.

The Copenhagen scientists examined hundreds of old aerial photographs taken for mapping work in 1937. The images were supplemented with a number of photographs taken in the 1950s and 1974 of the same area and a 3D computer reconstruction was produced. This allowed the researchers to examine the evolution of glaciers over a significant time period. In order to determine if recent trends exceed the scale of natural variability, long-term observations are said to be vital.

“Compared to modern data, the ice flow speeds are unchanged. While some glaciers have thinned over shorter intermediate periods of 10-20 years, they have remained stable or grown slightly in the long term, indicating a system in balance,” it was noted.

Actual long-term scientific observations will always beat media-friendly computer-modelled pseudoscientific opinions and alarm drummed up by short-term outliers. The authors note that using data from historical sources such as early photographs provides extensive coverage across large areas with detailed temporal and three-dimensional information. Geological evidence covers longer time scales with temporal uncertainties of thousands of years, while estimates from ice cores are generally very local and spatially confined. In Antarctica, it is pointed out, the scarcity of historical climate data makes climate reanalysis estimates before 1970 “largely uncertain”, while “observed trends cannot clearly be distinguished from natural variability”. Not that this stops mainstream activists such as Clive Cookson at the Financial Times who reacted to a recent two-year downward spike in Antarctica sea ice with the suggestion that the area faced a “catastrophic cascade of extreme environmental events… that will affect the climate around the world”.

Of course a “system in balance” is the last thing a Net Zero-obsessed mainstream wants to hear about. The Antarctica Circumpolar Current is the strongest flow of water on the planet and on March 4th the BBC brought news that it was “at risk of failing”. New research is said to suggest that the current will be 20% slower within 25 years “as the world warms, with far reaching consequences for life on Earth”.

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climate-debate

Now You Sea Ice, Now You Don’t

by W. Eschenbach, Apr 20, 2024 in WUWT

I got to thinking about sea ice and the climate models. Here’s what we know about polar sea ice extent, showing data that starts with the satellite era when we began to have accurate observations of the poles.

Figure 1. Arctic, Antarctic, and global sea ice extent. Colored lines are CEEMD smooths of the underlying datasets.

Now, there are some rather large curiosities regarding the sea ice extent records.

  • The North Pole is a liquid ocean covered with sea ice, with most of the ice polewards of 70°N. The South Pole is a giant chunk of frozen rock surrounded by sea ice, with almost no ice polewards of 70°S. So why do both poles have about the same extent of sea ice?
  • From the start of the satellite era up until ~2015, Arctic sea ice extent was decreasing and Antarctic sea ice extent was increasing … and as a result, total global sea ice extent was relatively constant, with 2014 having about the same global sea ice extent as 1978. Why?
  • Around 2015, Antarctic sea ice extent started dropping rapidly … but Arctic sea ice stopped dropping and leveled off up to the present. Why?
  • After dropping precipitously for a couple of years, Antarctic sea ice extent leveled off again … and as a result, global ice extent also leveled off. Why?

Here’s the interesting part. Nobody knows the answers to any of those questions. And I suppose predictably, since they’re based on our (mis)understandings of the climate, none of the climate models either forecasts or hindcasts sea ice extent doing anything even remotely similar to the actual observations.

So I’ll leave this here as a testament to just how little we understand the magnificent global heat engine that we call the climate …

climate-debate

Terrestrial temperature, sea levels and ice area links with solar activity and solar orbital motion

by V. Zharkova & I. Vasilieeva, Nov 2023

Abstract: This paper explores the links between terrestrial temperature, sea levels and ice areas in both hemispheres with solar activity indices expressed through averaged sunspot numbers together with the summary curve of eigen vectors of the solar background magnetic field (SBMF) and with changes of Sun-Earth distances caused by solar inertial motion resulting from the gravitation of large planets in the solar system.

Using the wavelet analysis of the GLB  and HadCRUTS datasets two periods: 21.4  and 36 years in GLB, set   and the period of about 19.6 years  in the HadCRUTS are discovered. The 21.4 year period is associated with variations in solar activity defined by the summary curve of the largest eigen vectors of the SBMF. A dominant 21.4-year period is also reported in the variations of the sea level, which is linked with the period of 21.4 years detected in the GLB temperature and the summary curve of the SBMF variations.  The wavelet analysis  of ice and snow areas shows that  in the Southern hemisphere it does not show any links to solar activity periods while in the Northern hemisphere the ice area  reveals  a period of 10.7 years equal to a usual solar acitviity cycle.

The TSI in March-August of every year  is found  to grow with every year following closely the temperature curve, because the Sun moves  closer to the Earth orbit owing to gravitation of large planets. (solar inertial motion, SIM). While the variations of solar radiation during a whole year have  more steady distribution without  a sharp TSI increase  during the last two centuries. The additional TSI contribution caused by SIM is likely to secure the additional energy input and exchange between the ocean and atmosphere.

 

Link to pre-print:  https://solargsm.com/wp-content/uploads/2023/11/zharkova_tsi_nc_form_subm-1.pdf

 

The paper is accepted for publication.

climate-debate

Greenland Icecap – 2023

By P. Homewood, Sep 2, 2023 in NotaLotofPeopleKnowThat

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As can be seen, the rate of loss in the last decade is similar to the 1930s, 50s and 60s. During the 1970s and 80s, Greenland’s climate grew much colder, and the ice mass loss almost stopped completely.

Significantly the rate of loss now is not accelerating, as you may have assumed from what the media have told you. On the contrary, the rate of loss has been slowing down since 2012.

The average annual loss between 2013 and 2022 was 184 Gt, which equates to 0.51mm sea level rise a year.

In short there is nothing alarming or unprecedented about the tiny amount of ice melt in Greenland.

better to know...?, climate-debate

NASA Data On Global Sea Ice Area Shows A Growth Equal To The Size Of Belgium Since 1982!

by P. Gosselin, Nov 30, 2021 in NoTricksZone

Global Sea Ice Area

Data analyst Zoe Phin just posted some interesting, surprising results on global sea ice area.

Data sources like the National Snow and Ice Data Center show global sea ice has been” drastically decreasing for a long time” and so we need to panic and overhaul the entire carbon economy. We hear this daily in the media.

Surprising global sea ice area findings

But Zoe has analyzed what she characterizes as a “very legitimate source” of data from NASA, (here, or here). And according to her findings, the data from these sources suggest global sea ice loss is not as dramatic as some institutes would like us to believe it is. In fact there ‘s been a gain!

Zoe plotted the data going back 40 years, from 1982 to 2021, the “Global Sea Ice Area Fraction”, which “is a proportion of the entire Earth’s surface that is ice over water.”

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“As you can see, about 3.6% (on average) of our planet’s area is covered in ice over water,” reports Zoe. “In the last 40 years, ice over water has INCREASED, and not decreased, as popularly claimed.”

According to Zoe, the observed increase is equivalent to ~30,600 km², or “roughly the size of Belgium”.

Northern hemisphere sea ice area has declined

The northern hemisphere has decreased, and this has gotten lots of attention from alarmists and the media:

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climate-debate

Media Regurgitate Nonsense About Greenland Ice Sheet And Sea Level Rise

by D. Burton, Apr 3, 2023 in ClimateChangeDispatch

CNBC and the Potsdam Institute (PIK) report that:

We’re halfway to a tipping point that would trigger 6 feet of sea-level rise from the melting of the Greenland Ice Sheet

PUBLISHED WED, MAR 29 202312:12 PM EDT By Catherine Clifford

KEY POINTS:

● Once people have cumulatively emitted approximately 1,000 gigatons of carbon in total, then the southern part of the Greenland Ice Sheet will melt eventually causing the sea level to rise by almost six feet.

● Once humans have cumulatively emitted approximately 2,500 gigatons of carbon in total, the whole Greenland Ice Sheet will eventually melt and the sea level rise would rise by 6.9 meters or 22.6 feet.

 

● And right now, now we are at approximately 500 gigatons of carbon emissions released.

Here’s the article.

Here’s the paper.

Like most things from PIK, this “study,” and this CNBC article, are nonsense. [emphasis, links added]

The best estimates are that since 1850, anthropogenic carbon emissions have totaled about 675 Gt of carbon (a/k/a PgC) (not 500).

Over that same period, the amount of CO2 in the atmosphere has increased by only about 135 ppmv CO2 = 287 PgC (gigatonnes carbon).

The difference is the amount removed from the atmosphere by natural negative feedbacks, such as absorption by the oceans, the greening of the Earth, and rock weathering.

(Aside: Petagram ≡ gigatonne ≡ Gt, and “PgC” means “petagram of carbon,” so 1 PgC = 1 Gt of carbon (GtC). 1 ppmv CO2 = 7.8024 Gt CO2 = 2.12940 PgC.)

Yet we’ve only gotten an estimated 1.02 to 1.27 °C of warming from all that CO2, and it’s beenaccompanied by negligible acceleration in sea-level trends:

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climate-debate

River longer than the Thames beneath Antarctic ice sheet could affect ice loss

by Imperial College London, Oct7, 2022 in ScienceDaily

An unexpected river under the Antarctic ice sheet affects the flow and melting of ice, potentially accelerating ice loss as the climate warms.

The 460km-long river is revealed in a new study, which details how it collects water at the base of the Antarctic ice sheet from an area the size of Germany and France combined. Its discovery shows the base of the ice sheet has more active water flow than previously thought, which could make it more susceptible to changes in climate.

The discovery was made by researchers at Imperial College London, the University of Waterloo, Canada, Universiti Malaysia Terengganu, and Newcastle University, with the details published today in Nature Geoscience.

Co-author Professor Martin Siegert, from the Grantham Institute at Imperial College London, said: “When we first discovered lakes beneath the Antarctic ice a couple of decades ago, we thought they were isolated from each other. Now we are starting to understand there are whole systems down there, interconnected by vast river networks, just as they might be if there weren’t thousands of metres of ice on top of them.

“The region where this study is based holds enough ice to raise the sea level globally by 4.3m. How much of this ice melts, and how quickly, is linked to how slippery the base of the ice is. The newly discovered river system could strongly influence this process.”

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unclassified

Greenland Mass Balance

by Andy May, Oct 25, 2022 in WUWT

The following is from Cap Allon’s excellent post here. We are all used to the mainstream media distorting climate science data and analysis, but he has uncovered a case that is beyond the pale. Consider this post a follow up to Dave Middleton’s post earlier the month.

Read on in Cap Allon’s words:

MSM OBFUSCATION

[Greenland’s ‘healthy’ melt season, was obscured across the mainstream media.]

CNN wrote the following in July 20 article: “The amount of ice that melted in Greenland between July 15 and 17 was enough to fill 7.2 million Olympic-sized swimming pools or cover the entire state of West Virginia with a foot of water.”

They even have a quote from cLiMaTe ScIeNtIsT Ted Scambos: “The northern melt this past week is not normal, looking at 30 to 40 years of climate averages. But melting has been on the increase, and this event was a spike in melt.”

CNN is screaming about this period of melting (circled below):

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climate-debate

Trend Change? Greenland Ice Mass Loss Has Been Decelerating Since 2012

by P. Gosselin, Sep 24, 2022 in NoTricksZone

We have digitized the Polar Portal’s graph of the accumulated surface mass balance and have come up with a value of 467 Gt. That’s 100 Gt or 27% above the 1981…2010 mean! Together with the melting of icebergs (assuming the value of the previous year, which was already 10% more than that of 2020 ) this results in approximately the representation below, which was included in the publication until the report 2020.

In 2021, one has probably omitted for reasons, perhaps the jump was difficult to explain by the calving of icebergs?

The total mass balance is very likely -100 Gt. An “accelerated” thawing of the Greenland ice sheet is not to be recognized. If one accumulates the mass loss, one sees the “braking” very nicely. Acceleration occurred until 2012.

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climate-debate

The Climate Scaremongers: The Great Arctic Sea Ice Scam

by P. Homewood, Sep 23, 2022 in ClimateChangeDispatch

 

 

For years the ‘experts’ have been telling us that the Arctic would soon be ice-free in summer.

Al Gore notoriously warned us in 2009 that ‘there is a 75 percent chance that the entire north polar ice cap, during the summer months, could be completely ice-free within five to seven years.’

He was, of course, just a politician. But a whole host of supposed Arctic scientists were all busy issuing similar warnings at the time. [bold, links added]

In 2007, for instance, Professor Wieslaw Maslowski told us that northern polar waters could be ice-free in summers within just five to six years.

In December of that year, Jay Zwally of Nasa agreed, giving the ice till 2012. A year later, in 2008 Professor David Barber went one step further, saying the ice would all be gone that very summer.

For sheer persistence in getting it wrong, however, the prize must go to Peter Wadhams, professor and head of the Polar Ocean Physics Group in the Department of Applied Mathematics and Theoretical Physics at the University of Cambridge:

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• In 2012, he predicted that the Arctic would be ice-free by 2015/16.

• In 2014, he thought it might last till 2020.

• In 2016, he confidently predicted the Arctic would be ice-free that summer (though curiously he now defined ‘ice-free’ as less than 1 million square kilometers).

All these pronouncements were designed for political propaganda purposes, not for scientific reasons, and were widely propagated by the gullible media.

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climate-debate

Germany’s Alfred Wegener Institute Sees No Extreme Situation With Arctic Sea Ice

by P. Gosselin, July 22, 2022 in NoTricksZone

The Alfred Wegner Institute does not see an extreme situation with sea ice in the Arctic (June 2022). The institute’s page states:

The Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI) is participating again this year with the AWI Consortium Model, a dynamic coupled sea ice ocean model, and calculated a September sea ice extent of 4.75 million square kilometers in its June forecast. This value is about 4% above the median value of all submitted models but in the middle of the predictions given for dynamic models.

Dr. Frank Kauker, a physicist in the Sea Ice Physics Section at AWI, assesses the first prediction as follows: “The first forecast of a year from the beginning of June is usually still characterized by a rather large uncertainty (this year 0.43 million square kilometers). Nevertheless, at the moment there is nothing to indicate an extreme situation in September.

The ice cover in September will be with a great probability in the range of the last years, i.e. between 4 and 5 million square kilometers. The next forecast in early July will reduce the uncertainty somewhat, as it will become clear in June how many melt ponds will have formed, which will then decisively determine the melt rates of the ice during the rest of the year due to their lower solar irradiance return.”

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unclassified

Climatologists Embarrassed: Increase In Global CO2 Levels Accompanied By Arctic Sea Ice Growth!

by P. Gosselin, July 26, 2022 in NoTricksZone

Today we look at the polar ice caps, which the global warming wingnuts claim is the canary in the coal mine and predicted earlier they’d melt and collapse. For example, Al Gore warned the Arctic ice would disappear by 2014.

While CO2 has gone up, Arctic sea ice has RISEN over past decade

But we have a big surprise. First we examine the Arctic sea ice extent so far this summer. Has it melted away like Al Gore said it would?

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Antarctica continues long-term upward sea ice trend

Looking at Antarctica sea ice, we also see a zero-crisis trend when plotting the data from the Japan Meteorological Agency (JMA):

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climate-debate

Mass balance of the Antarctic ice sheet 1992–2016: reconciling results from GRACE gravimetry with ICESat, ERS1/2 and Envisat altimetry

by J. Zwally et al., 2021, March 29, in J.of.Glaciology

Abstract

GRACE and ICESat Antarctic mass-balance differences are resolved utilizing their dependencies on corrections for changes in mass and volume of the same underlying mantle material forced by ice-loading changes. Modeled gravimetry corrections are 5.22 times altimetry corrections over East Antarctica (EA) and 4.51 times over West Antarctica (WA), with inferred mantle densities 4.75 and 4.11 g cm−3. Derived sensitivities (Sg, Sa) to bedrock motion enable calculation of motion (δB0) needed to equalize GRACE and ICESat mass changes during 2003–08. For EA, δB0 is −2.2 mm a−1 subsidence with mass matching at 150 Gt a−1, inland WA is −3.5 mm a−1 at 66 Gt a−1, and coastal WA is only −0.35 mm a−1 at −95 Gt a−1. WA subsidence is attributed to low mantle viscosity with faster responses to post-LGM deglaciation and to ice growth during Holocene grounding-line readvance. EA subsidence is attributed to Holocene dynamic thickening. With Antarctic Peninsula loss of −26 Gt a−1, the Antarctic total gain is 95 ± 25 Gt a−1 during 2003–08, compared to 144 ± 61 Gt a−1 from ERS1/2 during 1992–2001. Beginning in 2009, large increases in coastal WA dynamic losses overcame long-term EA and inland WA gains bringing Antarctica close to balance at −12 ± 64 Gt a−1 by 2012–16.

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better to know...?, climate-debate

The NOT melting glacier

by T. Ciccone & J. Lehr, May 31, 2022 in CFact

beautiful white icy hill with cave in antarctic

 

Could Antarctica’s ‘Doomsday Glacier’ meet its doom within 3 years?

“Time is melting away for one of Antarctica’s biggest glaciers, and its rapid deterioration could end with the ice shelf’s complete collapse in just a few years,” alarmist researchers warned at a virtual press briefing on Dec. 13, 2021 at the annual meeting of the American Geophysical Union (AGU)–a once outstanding professional society, but now a shill for the left.

Above is the first sentence of the article titled “Antarctica’s ‘Doomsday Glacier’ could meet its doom within 3 years,” not what we would expect to see from a once reputable source, the AGU. It warns us that in a few years, the world’s largest glacier, about the size of Florida, will melt and raise ocean levels by up to 3 meters (about 10 ft). It then tells us that the glacier is melting from below because the surrounding ocean waters have been warmed “thanks to human-induced climate change.” Finally, it tells us that a team of more than 100 scientists from the USA and the UK have been studying the Thwaites glacier and sharing their findings with scientists worldwide.

The article then explains that the Thwaites is not melting from above, but “the melting is coming from below,” from the warmed-up oceans that have been warmed by human-made CO2 and the greenhouse effect. The bulk of the article then proceeds to detail the forecasted consequences around the world:

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This team may not have even been communicating with each other. Almost a decade earlier, geologists were seeing evidence of volcanoes in a known active tectonic plate boundary, buried under the glacier and the oceans. Before 2017, at least 47 volcanoes were found in western Antarctica and around the area of the Thwaites glacier. In 2017 the Guardian reported that an additional 91 volcanoes had been found along the western shores of Antarctica, with some sitting under the Twaites glacier itself. See the article “Scientists discover 91 volcanoes below Antarctic ice sheet.”

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better to know...?, climate-debate

ON SATURDAY, GREENLAND’S SURFACE MASS BALANCE GAINED A RECORD-SMASHING 7 GIGATONS…

by Cap Allon, June 20, 2022 in Electroverse

If you want proof of mainstream media manipulation and agenda driving drivel, you need look no further than the “official” reporting of the Greenland ice sheet–the poster child for anthropogenic global warming. If today’s intensifying energy crisis wasn’t rooted in said obfuscations, all of this would be laughable.

Impressive surface mass balance (SMB) readings –a calculation to determine the ‘health’ of a glacier– have been posted across the Greenland ice sheet all season. But the cherry, at least for me, is taken by Saturday’s record-smashing 7 Gigaton GAIN–particularly when you consider the glacier should be losing mass at this time of year.

The MSM appears to love dumb, decontextualized headlines to advance their AGW narrative. So here’s one for them:

Greenland’s Recent SMB Gains Enough To Bury Central Park, New York City Under 7,833 Feet Of Ice… (it’s true, do the math).

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climate-debate

Facts About the Arctic in May 2022

by J. Hunt, Apr 30, 2022 in TheGreatWhite Con

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There’s a few things to note at first glance. The ice floe continued to decrease in thickness into November. It’s thickness then started to increase, but is currently still less than 2 meters. Also the snow depth has gradually been increasing, and (apart from some data glitches!) is now ~38 cm. Finally, for the moment at least, the ice surface temperature has been slowly warming since mid February and is now ~-11 °C.

 

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better to know...?, climate-debate

Arctic Sea Ice Stabilizes, No Trend Reduction In More Than 10 Years As Solar Cycle Starts Off Weakly

by P. Gosselin, Apr 27, 2022 in NoTricksZone

The Copernicus program offers very interesting data on Arctic ice.

While sea ice has been declining off the Greenland Sea (east of the island), the Chucki Sea (eastern Siberia) shows a very different trend in sea ice extent over the past year. Such deviations have occurred repeatedly since the year 2000.

Overall, the 2021 extent was very close to the 1991-2020 mean and well above the lowest value in 2012 and also above what was recorded in the year 2020

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climate and geology

Ancient Ice Reveals Scores of Gigantic Volcanic Eruptions

by C. Rotter, Mar 15, 2022 in WUWT/ClimPast

Magnitude, frequency and climate forcing of global volcanism during the last glacial period as seen in Greenland and Antarctic ice cores (60–9 ka)

Abstract

Large volcanic eruptions occurring in the last glacial period can be detected by their accompanying sulfuric acid deposition in continuous ice cores. Here we employ continuous sulfate and sulfur records from three Greenland and three Antarctic ice cores to estimate the emission strength, the frequency and the climatic forcing of large volcanic eruptions that occurred during the second half of the last glacial period and the early Holocene, 60–9 kyr before 2000 CE (b2k). Over most of the investigated interval the ice cores are synchronized, making it possible to distinguish large eruptions with a global sulfate distribution from eruptions detectable in one hemisphere only. Due to limited data resolution and large variability in the sulfate background signal, particularly in the Greenland glacial climate, we only list Greenland sulfate depositions larger than 20 kg km−2 and Antarctic sulfate depositions larger than 10 kg km−2. With those restrictions, we identify 1113 volcanic eruptions in Greenland and 737 eruptions in Antarctica within the 51 kyr period – for which the sulfate deposition of 85 eruptions is found at both poles (bipolar eruptions). Based on the ratio of Greenland and Antarctic sulfate deposition, we estimate the latitudinal band of the bipolar eruptions and assess their approximate climatic forcing based on established methods. A total of 25 of the identified bipolar eruptions are larger than any volcanic eruption occurring in the last 2500 years, and 69 eruptions are estimated to have larger sulfur emission strengths than the Tambora, Indonesia, eruption (1815 CE). Throughout the investigated period, the frequency of volcanic eruptions is rather constant and comparable to that of recent times. During the deglacial period (16–9 ka b2k), however, there is a notable increase in the frequency of volcanic events recorded in Greenland and an obvious increase in the fraction of very large eruptions. For Antarctica, the deglacial period cannot be distinguished from other periods. This confirms the suggestion that the isostatic unloading of the Northern Hemisphere (NH) ice sheets may be related to the enhanced NH volcanic activity. Our ice-core-based volcanic sulfate records provide the atmospheric sulfate burden and estimates of climate forcing for further research on climate impact and understanding the mechanism of the Earth system.How to cite. Lin, J., Svensson, A., Hvidberg, C. S., Lohmann, J., Kristiansen, S., Dahl-Jensen, D., Steffensen, J. P., Rasmussen, S. O., Cook, E., Kjær, H. A., Vinther, B. M., Fischer, H., Stocker, T., Sigl, M., Bigler, M., Severi, M., Traversi, R., and Mulvaney, R.: Magnitude, frequency and climate forcing of global volcanism during the last glacial period as seen in Greenland and Antarctic ice cores (60–9 ka), Clim. Past, 18, 485–506, https://doi.org/10.5194/cp-18-485-2022,

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