Archives par mot-clé : Antarctic

better to know...?, climate-debate

ANTARCTICA SUFFERING COLDEST JANUARY SINCE 1978 + GLOBAL SEA ICE GROWING EXPONENTIALLY

by Cap Allon, Jan 20, 2021 in Electroverse

The start of 2021 in Antarctica has been an unusually chilly one. In fact, the first half of January has been the coldest since 1978, according to data compiled by @LpdlcRamirez and @peikko763 on Twitter.

As of Jan. 19, the month-to-date temperature anomaly across Antarctic is approx. -0.5C, making this the continents coldest first 3-or-so-weeks of Jan. since 1978 (solar minimum of cycle 20), according to research conducted by @peikko163 on Twitter, who also notes that the Southern Hemisphere as a whole is suffering anomalous January chills not seen since 2012.

But this chill of solar minimum isn’t just confined to the Southern Hemisphere either, the mercury ACROSS the planet is tumbling. In one month global temperatures dropped by a whopping 0.26C: from 0.53C above the 1981-2010 avg. in Nov. 2020 to just 0.27C above the avg. in Dec. 2020 (UAH). This drop was in spite of a warming Arctic–a region expected to “heat” during times of otherwise “global” cooling (more on that below).

The Sun appears to be sliding into its next Grand Solar Minimum cycle–a multidecadal spell of reduced solar output where the solar disc can be devoid of sunspots for months or even years at a time. The result on Earth’s climate will be one of violent swings between extremes due to a weakening of the jet streams: intense bursts of heat will linger in one area, while a teeth-chattering chill will dominate nearby, and then the regions will “switch” — it is this unpredictable chopping and changing that will hasten the failure of our modern food production systems: crops will fail, on a large scale, and famine could quickly ensue.

Overall, Earth’s temperature trends colder during a Grand Solar Minimum, as the Sun’s output sinks lower and lower (increased cloud nucleation being one likely forcing). However, not ALL regions experience the chill: as with the previous GSM (the Maunder Minimum 1645-1715), areas such as the Arctic, Alaska, and S. Greenland/N. Atlantic actually warmed while the rest of the planet cooled — NASA reveals the phenomenon in their Maunder Minimum temperature reconstruction map:

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climate-debate

Peer-Reviewed Study Confirms Antarctica Has Not Warmed in Last Seven Decades

by P. Homewood, Jan 16, 2021 in NotaLotofPeopleKnowThat

Cancel all the claims by climate activists that global warming is decimating Antarctica. A peer-reviewed study recently published in one of the most prominent science journals destroys one of the most frequently asserted claims by climate activists – that climate change is warming Antarctica and melting the Antarctic ice sheet. The recent study confirms Antarctica has not warmed in the past 70 years and Antarctic ice cover is expanding rather than shrinking.

Writing in the journal Nature, scientists at Columbia University and the University of Victoria, British Columbia report, “The Antarctic continent has not warmed in the last seven decades, despite a monotonic increase in the atmospheric concentration of greenhouse gases.”

 

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pollution-contamination

Microplastic pollution in Antarctic waters mirrors rates in North Atlantic and Mediterranean

by E. Quinn, Oct 26, 2020 in EyeOn Arctic

Microplastics have been identified in Antarctic waters at rates that mirror the amounts found in oceans elsewhere in the world, including the North Atlantic, says a new study.

“Although no difference in microplastic abundance was found among regions, the values were much higher in comparison to less remote ecosystems, suggesting that the Antarctic and Southern Ocean deep-sea accumulates higher numbers of microplastic pollution than previously expected,” said the authors in the abstract of the paper “High Abundances of Microplastic Pollution in Deep-Sea Sediments: Evidence from Antarctica and the Southern Ocean,” published Friday in the the journal Environmental Science & Technology.

Waters in three areas around Antarctica were sampled for the study: the Antarctic Peninsula, South Sandwich Islands, and South Georgia.

Levels “surprising”

Microplastic is the term used to describe plastics less than, or equal to 5mm.

The study found that just over one particle of microplastic was found in each gram of sediment in each of the three areas.  This rate of microplastics mirrors the amounts found in other oceans that are considerably closer to human settlements.

“Our research highlights that no matter how remote an ecosystem is, it will still show the artefacts of human influence,” said Mánus Cunningham, a researcher from Queen’s University in Belfast, in a news release.

“We have been dumping plastic into our oceans for roughly 70 years now, so in hindsight this may not be terribly surprising. What is surprising is that the levels of this type of pollution are comparable to what we consider moderately or highly polluted regions of the world’s oceans.”

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better to know...?

Atmospheric rivers help create massive holes in Antarctic sea ice

by Rutgers University, Nov 15, 2020 in WUWT

Warm, moist rivers of air in Antarctica play a key role in creating massive holes in sea ice in the Weddell Sea and may influence ocean conditions around the vast continent as well as climate change, according to Rutgers co-authored research.

Scientists studied the role of long, intense plumes of warm, moist air – known as atmospheric rivers – in creating enormous openings in sea ice. They focused on the Weddell Sea region of the Southern Ocean near Antarctica, where these sea ice holes (called polynyas) infrequently develop during the winter. A large hole in this area was first observed in 1973 and a hole developed again in the late winter and early spring of 2017.

IMAGE: A BAND OF CLOUDS IN AN ATMOSPHERIC RIVER EXTENDING FROM SOUTH AMERICA TO THE ANTARCTIC SEA ICE ZONE ON SEPT. 16, 2017. view more CREDIT: NASA

In the first study of its kind, published in the journal Science Advances, scientists found that repeated strong atmospheric rivers during late August through mid-September 2017 played a crucial role in forming the sea ice hole. These rivers brought warm, moist air from the coast of South America to the polar environment, warming the sea ice surface and making it vulnerable to melting.

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climate-debate

How to Scare and Deceive without Lying: JPL Cries Wolf about Polar Glacial Melt

by C. Beisner, Nov 6, 2020 in WUWT

Yesterday NASA’s Jet Propulsion Laboratory published “The Anatomy of Glacial Ice Loss.” For the most part it’s an interesting, though not particularly revolutionary, discussion of the various forces that add to and subtract from glacial ice. Nothing wrong with that.

But its authors took the opportunity to insert a poison pill, a little bit of fearmongering, in a video caption:

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Did you catch that little trick? “Combined, the two regions also contain enough ice, that if it were to melt all at once, would raise sea levels by nearly 215 feet ….”

Well, yes, but at what rate is the ice from the two regions melting, and at what rate can we, with any confidence, predict they’ll continue to melt, and over what period of time?

There is absolutely no chance of their melting “all at once”—barring, I suppose, Earth’s collision with some enormous asteroid that sends Earth careening into the Sun!

So, how fast is the ice melting?

For Greenland, about 0.1% of its ice mass per decade—1 percent per century.

For Antarctica, about 0.0045% per decade—1% in 2,200 years.

Combined, those contribute to sea-level rise of about 1 mm per year, i.e., 3.94 inches per century.

(See “Lying with Statistics: The National Climate Assessment Falsely Hypes Ice Loss in Greenland and Antarctica.”)

So, if the actual rate is about 3.94 inches (0.3283 foot) per century, how long would it take to raise sea level by 215 feet? The answer: 215 ft. / 0.3283 ft. per century = 654.889 centuries, or 65,488.9 years.

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climate-debate

Sea level rise and Antarctica

by Jim Steele, Nov 4, 2020 in WUWT

California’s and other American coastal towns are engaged in divisive arguments regards rising sea levels. Although observed sea levels rose less than 8 inches (0.08 inches per year) since 1900, some modelers forecast much bleaker futures. They predict a 2.4-foot rise for every 1°F rise above preindustrial temperatures, then accelerating to nearly 4.5 feet for every 1°F additional increase. Why a dramatic acceleration in sea level? It’s based primarily on dire models, typically presented to coastal planning commissions as ‘best science’, suggesting increasing ice instability and Antarctica ice sheet collapse. “Antarctica has the potential to contribute more than 3.3 feet of sea-level rise by 2100 and more than 49 feet by 2500.”

Those models have prompted some citizens to argue we must abandon the coasts via managed retreat. Others argue we should build better sea walls. But how high? Others rightfully ask, “how trustworthy are those models?” Model predictions of a collapsing Antarctica ice sheet are not based on observations.  Models of Antarctica’s catastrophic ice collapse are attempts to explain ancient sea levels such as the 30-foot higher levels 120,000 years ago.

There are good reasons toquestion catastrophic models. For one, away from the coast Antarctica’s surface temperatures average −70 °F. Antarctica’s extremely cold surfacesrequire global warming to increase many, many times more before surface glaciers could ever melt. For another, although greenhouse theory predicts increasing CO2  concentrations will raise temperatures, greenhouse theory also predicts added CO2  has a cooling effect on Antarctica (Wijngaarden & Happer 2020, Schmithüsen 2015).

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better to know...?, climate-debate

NSIDC: 2020 POLAR ICE DOING JUST FINE

by Cap Allon, Oct 24, 2020 in Electroverse

According to the latest October report from the National Snow and Ice Data Center (NSIDC), the ice locked at Earth’s poles is, overall, GROWING.

By volume, Antarctica contains 90% of Earth’s ice, and volume is a far better metric to use when judging the state of an ice sheet than sea ice extent. Extent is prone to wild and unpredictable fluctuations due to natural changes in ocean currents and wind patterns, etc–though these fluctuations are of a much lesser degree in Antarctica than in its northern cousin, the Arctic.

According to the latest NSIDC report, Antarctic sea ice extent reached a whopping 18.95 million square kilometers (7.32 million square miles) on September 28. Mid to late Sept would usually give us the year’s maximum extent, but given the favorable conditions in October, the maximum may well be higher. “As is typical this time of year, there are wide swings caused by winds and storms along the extensive ice edge,” writes the NSIDC.

Ice extent around Antarctica is now “well above the 1981 to 2020 median extent,” the NSIDC informs us. “Ice extent is above the median extent along a broad area off the Wilkes Land coast and western Ross Sea, near the median extent from the Amundsen Sea clockwise to the Weddell Sea and above the median north of Dronning Maud Land, Enderby Land, and the Cosmonaut Sea. The only major area of below the median extent is in the Indian Ocean sector near the Amery Ice Shelf and eastward.”

Continuer la lecture de NSIDC: 2020 POLAR ICE DOING JUST FINE →

climate-debate

New Study: East Antarctica Was Up To 6°C Warmer Than Today During The Medieval Warm Period

by K. Richard, Oct 15, 2020 in NoTricksZone

As recently as 2000 to 1000 years ago, spanning the Roman to Medieval Warm Periods, East Antarctica was 5-6°C warmer than it is today. The consequent ice melt resulted in >60 meters higher water levels in East Antarctica’s lakes.

East Antarctica has been rapidly cooling in recent decades, with magnitudes reaching -0.7°C to -2.0°C per decade since the mid-1980s (Obryk et al., 2020).

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A new study (Myers et al., 2020) reports that until about 15,000 years ago and throughout the Last Glacial Maximum, East Antarctica was 4-9°C colder than it is today.

Antarctica then abruptly warmed 15°C within centuries. From 12,000 to 6,000 years before present, East Antarctica was about 5°C warmer than it is today.

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climate-debate

Claim: Sea level rise from ice sheets track worst-case climate change scenario

by University of Leeds, September 1, 2020 in WUWT/Nature

Ice sheets in Greenland and Antarctica whose melting rates are rapidly increasing have raised the global sea level by 1.8cm since the 1990s, and are matching the Intergovernmental Panel on Climate Change’s worst-case climate warming scenarios.

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So far, global sea levels have increased in the most part through a mechanism called thermal expansion, which means that volume of seawater expands as it gets warmer. But in the last five years, ice melt from the ice sheets and mountain glaciers has overtaken global warming as the main cause of rising sea levels.

Dr Ruth Mottram, study co-author and climate researcher at the Danish Meteorological Institute, said: “It is not only Antarctica and Greenland that are causing the water to rise. In recent years, thousands of smaller glaciers have begun to melt or disappear altogether, as we saw with the glacier Ok in Iceland, which was declared “dead” in 2014. This means that melting of ice has now taken over as the main contributor of sea level rise. “

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Further information

The study, “Ice-sheet losses track high-end sea-level rise projections,” is published today (31 August) in Nature Climate Change.

View towards Icefjord in Ilulissat. Easy hiking route to the famous Kangia glacier in Greenland. The Ilulissat Icefjord seen from the viewpoint. Declared a UNESCO World Heritage Site in 2004. Photo taken in Greenland.

better to know...?, climate-debate

ANTARCTIC SEA ICE EXTENT IS CURRENTLY EXCEEDING THE 1981-2010 AVERAGE BY 233,000 KM2, AND GROWING!

by Cap Allon, August 30, 2020 in Electroverse

Climate alarmists take note: the ice locked within Antarctica is far more important to your hokey climate change theories than that which is contained in its northern cousin, the Arctic; the southern pole contains 90% of Earth’s ice.

According to official government data from the National Snow & Ice Data Center (NSIDC), 2020’s Antarctic Sea Ice Extent has been increasing rapidly this month, to levels rarely seen since record-keeping began 4+ decades ago.

The latest data-point –from day 241 (or Aug 28)– reveals extent is currently standing at 18.354 million km2, compared with the 1981-2010 ‘day 241’ average of 18.131 million km2 — and by my crude calculations, that’s an AGW-destroying 233,000 km2 more:

[nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph]

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climate-debate

by Cap Allon, August 7, 2020 in Electroverse

According to official government data from the National Snow & Ice Data Center (NSIDC), 2020’s Antarctic Sea Ice Extent is tracking the 1979-1990 average.

Climate alarmists take note, the ice locked within Antarctica is far more important to your hokey climate theories than that contained in its northern cousin the Arctic.

The Antarctic contains 90% of our planet’s ice, and, therefore, if Antarctica isn’t melting then any potential sea-level rise will be severely limited.

And Antarctica isn’t melting.

According to the latest NSIDC data, sea ice extent around the southern pole has been tracking the 1979-1990 average ALL YEAR:

[nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph]

In addition, August 2020’s extent is currently greater than it was in the 1980s:

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climate-debate

DESPITE THE LIES, THE SPIN, AND THE PROPAGANDA, ANTARCTIC SEA ICE IS GROWING — BOTH EXTENT AND CONCENTRATION GREATER NOW THAN IN 1980

by Cap Allon, July 6, 2020 in Electroverse

The UN and their scraggly little offshoot, the IPCC, are at it again — obfuscating data in order to push their fraudulent catastrophic global warming agenda.

According to the IPCC, and picked up the usual AGW propaganda rags such as the Guardian: “the South pole is warming three times faster than rest of the world.”

The Guardian articledated June 30, 2020 continues in predictably befogging fashion: “Dramatic change in Antarctica’s interior in past three decades a result of effects from tropical variability working together with increasing greenhouse gases.”

But, 1) the MSM have a habit of claiming everywhere is warming faster than everywhere else:

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And 2), the actual data reveals quite the opposite re Antarctica.

As @Harry_Hardrada recently pointed out on Twitter, there was a larger extent and concentration of Antarctic Sea Ice in June 2020 than back in June 1980:

Robert Felix over at iceagenow.com dives into the data, adding that sea ice extent today stands at 700,000 sq km (270,272 sq miles) greater than in 1980.

And in case you’re having a hard time reading the numbers, Felix breaks them down for you:

Sea ice extent in June 2020 = 13.2 million sq km
Sea ice extent in June 1980 = 12.5 million sq km

Sea ice concentration in June 2020 = 10.6 million sq km
Sea ice concentration in June 1980 = 9.6 million sq km

Fact-checked!

That’s enough extra ice to entirely cover Maryland, Delaware, West Virginia, South Carolina, Virginia, Indiana, Ohio and all six New England states. Oh, and throw in Washington, D.C. for good measure. (Which might be a good idea.)

 See also THE ARCTIC IS ON FIRE, AND WE SHOULD ALL BE TERRIFIED” — FACT CHECK: IT’S CURRENTLY SNOWING IN VERKHOYANSK

climate-debate

A “Good” Proxy on the Antarctic Peninsula?

by Steve McIntyre, June 30, 2014 in ClimateAudit

Nearly all of the text of this article on an interesting ice core proxy series (James Ross Island) from the Antarctic Peninsula was written in June 2014, but not finished at the time for reasons that I don’t recall.  This proxy was one of 16 proxy series in the Kaufman 12K pdf. 60-90S reconstruction.

I originally drafted the article because it seemed to me that the then new James Ross Island isotope series exemplified many features of a “good” proxy according to ex ante criteria that I had loosely formulated from time to time in critiquing “bad” proxies, but never really codified (in large part, because it’s not easy to codify criteria except through handling data.)

Although this series is in the Kaufman 60-90S reconstruction, its appearance is quite different than the final 60-90S reconstruction: indeed, it has a very negative correlation (-0.61) to Kaufman’s final CPS reconstruction. I’ll discuss that in a different article.

Following is mostly 2014 notes, with some minot updating for context.

“Good” Proxies
I’ve articulated with increasing clarity over the years (but present in early work as well) – is that one needs to work outward from proxies that are “good” according to some ex ante criteria, rather than place hope in a complicated multivariate algorithm on inconsistent and noisy data, not all of which are “proxies” for the item being reconstructed. This is based on principles that I’ve observed in use by geophysicists and geologists to combine “good” (high resolution) data with lower quality data.

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climate-debate

A HISTORY OF THE ADVANCE AND RETREAT OF ALPINE GLACIERS

by Cap Allon, June 23, 2020 in Electroverse

It should be obvious after watching that glacial advances and retreats have always occurred and that they must therefore be the result of natural forcings.

On the back of decades of historically high solar activity, modern human’s witnessed a gradual glacial melt. But now, the Sun is once again shutting down, and the evidence for a return to glacial advance is ever-building:

The Greenland Ice Sheet continues to gain record amounts of snow & ice:

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climate-debate

Natural Variability Behind West Antarctic Warming—Media Silent

by D. Whitehouse, June 19,2020 in ClimateChangeDispatch

Ten days ago the journal Science issued an embargoed press release about a forthcoming paper that suggested the warming observed in West Antarctica was due to natural climatic variability.

West Antarctica has always been looked on by alarmists as being the southern example of polar temperature amplification – a phenomenon predicted by most climate change models.

The Arctic temperature amplification is very apparent so there must be an Antarctic equivalent, and there it is.

But while scientists have been well aware that Antarctica is warming asymmetrically, with West Antarctica experiencing more than East Antarctica and frequently attributed to climate change, the underlying causes of this phenomenon have been poorly understood, and the suggestion that West Antarctica may be experiencing natural warming has been suggested before though not taken up very enthusiastically, if at all.

This new paper, “The internal origin of the west-east asymmetry of Antarctic climate change”, expresses the dilemma well.

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climate-debate

The Yin and Yang of Holocene Polar Regions Andy May / 1 day ago May 27, 2020

by R. Hannon/A. May, May 27, 2020 in WUWT

Introduction

The Arctic and Antarctic regions are different and yet similar in many ways. The Arctic has ocean surrounded by land and the Antarctic is a continent surrounded by water. Both are cold, glaciated and located at Earth’s poles some 11,000 miles apart. While sea ice has been retreating in the Arctic, it has been relatively stable in the Antarctic. This post examines surface temperature trends, solar insolation, and CO2 at the polar Arctic and Antarctic regions during the Holocene interglacial period.

 

 

Continuer la lecture de The Yin and Yang of Holocene Polar Regions Andy May / 1 day ago May 27, 2020 →

climate-debate

Antarctic Avery Ice Shelf “Prograding Considerably In Last 2 Decades”, Team Of Scientists Find

by P. Gosselin, May 6, 2020 in NoTricksZone

A newly released paper by Kumar et al looks at the changes and prediction of the Amery Ice Shelf (AIS) of East Antarctica using remote sensing data.

The scientists found that the ice shelf is prograding (expanding), and not breaking apart like some alarmist scientists feared earlier.

Image: cropped from Wikipedia. 

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Continuer la lecture de Antarctic Avery Ice Shelf “Prograding Considerably In Last 2 Decades”, Team Of Scientists Find →

climate-debate

Claim: Antarctic Sea Ice Growth Caused by Meltwater

by Eric Worrall, May 7, 2020 in WUWT

According to climate scientists, less dense meltwater on the surface of the Antarctic ocean reduced convection between the surface and ocean depths, leaving heat trapped in the depths.

A

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Don’t you love climate science? When sea ice accumulates, scientists adjust the models until they get the right result. When the sea ice melts, well that is what you would expect from global warming.

climate and geology, climate-debate

L’Antarctique géologique (2/2)

by A. Préat, 1 mai 2020 in ScienceClimatEnergie

Cet article fait suite aux trois récents articles publiés par le Prof. Maurin sur SCE (1/3, 2/3,  3/3), et traite de l’évolution géologique de la plaque Antarctica.
Voir également L’Antarctique géologique (1/2).

3/ Situation récente à l’échelle géologique

3.1. Isolation de la plaque Antarctique

Nous arrivons ainsi à la situation actuelle avec l’Arctique et l’Antarctique, situation décrite dans les parties 1 à 3 des articles de M. Maurin (parties 1/3, 2/3 et 3/3). D’où proviennent les glaciations actuelles ? Pour les comprendre il faut remonter au début de l’ère cénozoïque en considérant l’Antarctique qui était en position polaire (Scotese, 2001).

La plaque antarctique, partie intégrante de l’ensemble des continents formant le Gondwana est entourée dès le Jurassique (Figs. 7 et 12, inL’Antarctique géologique 1/2) de rides médio-océaniques (excepté la péninsule antarctique qui provient d’une limite de plaque convergente active avec failles transformantes séparant la plaque Antarctique et la plaque Scotia). En conséquence, la plaque Antarctique est actuellement en expansion par rapport aux plaques adjacentes, et fut particulièrement stable et isolée par rapport aux événements tectoniques du Mésozoïque et du Cénozoïque (ici).

Dans ce contexte, et en remontant le temps, il faut noter l’individualisation, dès l’Ordovicien, de la péninsule antarctique avec des montagnes de plus de 3200 m d’altitude constituant aujourd’hui la région la plus au nord de l’Antarctique occidental et s’étendant au-delà du cercle polaire. Cette chaîne de montagnes prolonge les Andes de l’Amérique du Sud dans la continuité d’une dorsale sous-marine caractérisée par un gradient géothermique élevé (voir plus loin). Ainsi on voit que l’Antarctique, depuis longtemps et encore aujourd’hui, participe à un jeu de tectonique des plaques encore active avec des effets locaux (notamment variations du  gradient géothermique).Ce gradient géothermique est un élément important à prendre en considération dans la dynamique glaciaire car il favorise la fonte et ensuite le glissement des glaces.

Notons que Arctowski (in Fogg 1992) avait déjà suggéré en 1901 que les Andes étaient présentes dans la pointe nord de la péninsule antarctique (Graham Land) .

3.2. Englacement de la plaque Antarctique

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Fig. 16 : Image des fonds marins d’une chaîne de 800 km de long de plusieurs volcans actifs de 1000 m de haut situés à proximité de la partie nord du continent antarctique. D’après Kamis, 2016.

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climate and geology

L’Antarctique géologique (1/2)

by A. Préat, 24 avril 2020 in ScienceClimatEnergie

Cet article traite de l’évolution géologique de la plaque Antarctica, et fait suite aux trois récents articles publiés dans SCE par le Prof. Maurin sur la cryosphère actuelle (1/3, 2/3,  3/3).

1/ Les glaces fascinent …

Les glaces fascinent depuis longtemps les climatologues qui y voient un monde à part, aujourd’hui elles sont suivies ‘à la loupe’ car elles témoigneraient en tout ou en partie du processus de réchauffement actuel. Elles sont l’objet d’une attention médiatique constante. Pourtant elles furent souvent absentes de la Planète, elles apparurent plusieurs fois et disparurent autant de fois au cours de l’histoire géologique, le plus souvent suivant des modalités différentes à l’échelle temporelle et spatiale.

Il n’est pas possible ici de retracer la longue histoire des glaces qui commence au Précambrien, au moins à la transition Archéen et Protérozoïque (avec la glaciation huronienne, il y a environ 2,4 Ga, pour l’échelle détaillée des temps géologiques voir ici, et ci-dessous (Fig. 1) pour une version simplifiée) et se poursuit avec des aléas divers avec un recouvrement des glaces sur l’ensemble de la Planète à la fin du Néoprotérozoïque, donc y compris dans la zone équatoriale, donnant lieu au fameux ‘Snowball Earth’ ou hypothèse de la Terre boule de neige ou encore ‘Terre gelée’ (glaciation marinoenne qui a fait suite à la -ou les ? glaciation(s) sturtienne(s)- il y a 635 Ma. Ensuite viendra la glaciation Gaskiers vers 580 Ma, c’est-à-dire vers la fin du Précambrien. Cet épisode marinoen d’englacement généralisé perdura plus d’une dizaine de millions d’années avec des calottes de glace sur l’équateur (ici) et est à l’origine du nom de l’avant-dernière période du Précambrien, à savoir le Cryogénien (partie supérieure du Protérozoïque entre 850 Ma et 635 Ma, cf. Fig. 1). Entre ces deux grandes glaciations précambriennes (celles de l’huronien et du marinoen), soit sur un peu plus de 1,5 Ga  aucune autre glaciation n’a encore? été rapportée, ce qui supposerait que pendant cet intervalle de temps le climat s’est maintenu dans des conditions plutôt chaudes, avec une régulation thermique ‘sans faille’ (Ramstein, 2015). Notons également pour être complet la présence de glaciers locaux à 2,9 Ga dans l’Archéen d’Afrique du Sud (glaciation ‘pongolienne’) (ici).

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climate-debate

Les glaces terrestres, la cryosphère (2/3)

by J.C. Maurin, 27 mars 2020 in ScienceClimatEnergie

Partie 2/3 : Lecture critique du chapitre cryosphère de l’AR5

par J.C. Maurin, Professeur agrégé de physique

Cette deuxième partie de l’article examine la composition du chapitre 4 du 5ème rapport du GIEC (AR5) [1].
Dans ce chapitre, qui concerne les différentes composantes de la cryosphère, les banquises [2] et glaciers [3] sont particulièrement mises en avant par les rédacteurs du GIEC.
A propos de ces 2 composantes mineures (0,65 % du volume de la cryosphère), l’article développe certains éléments d’appréciation que les rédacteurs de l’AR5 n’ont pas mis en exergue.

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Continuer la lecture de Les glaces terrestres, la cryosphère (2/3) →

unclassified

Denman Glacier–Latest Antarctic Meltdown Scare

by P. Homewood, March 24, 2020 in NotaLotofPeopleKnowThat

Scientists have found a new point of major vulnerability in the Antarctic ice sheet, in a region that already appears to be changing as the climate warms and has the potential to raise sea levels by nearly five feet over the long term.

Denman glacier, in East Antarctica, is a 12-mile-wide stream of ice that flows over the deepest undersea canyon in the entire ice sheet before spilling out into the ocean. That subsea trough is more than 2 miles deep, or double the average depth of the Grand Canyon. While there are far deeper trenches in the open ocean, such as the Marianas Trench, in this case the extreme undersea topography lies right on the outer fringe of the Antarctic continent — making it the “deepest continental point on Earth.”

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In reality the scientists who wrote this study do not have a clue whether the retreat of the Denman is anything new or not, or whether the deep ocean temperatures are any warmer than before 1979. Or whether what they are observing is just a natural process.

 

We can then go on to explore sea level implications.

They claim that since 1979, 250 billion tonnes of ice has been lost, equivalent to 0.5mm of sea level rise. In other words, 1.3mm/C, hardly cataclysmic.

They then go on to talk about a potential loss of 540 trillion tonnes, raising sea levels by 5 feet. Yet at current rates, it would take 86400 years for this to occur!

As always with these sort of studies, the authors refuse to say how long all this will take to happen.

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climate-debate

ANTARCTICA JUST SET ITS COLDEST MARCH TEMPERATURE ON RECORD: A “GLOBAL WARMING” DESTROYING -75.3C (-103.5F)

by Cap Allon, March 23, 2020 in Electroverse

The MSM has a blatant warm-bias, that’s been clear for years…

A myriad of news outlets were all-too-happy to run with the Antarctic Peninsula’s record warm temperature last month, painting it as further evidence of the coming climate catastrophe (despite the peninsula actually being located closer to Argentina than the South Pole, and the event officially going down as a foehn). But where are those same rags now? Where is their balance? Their credibility? Or is informing the public not the goal anymore, is their mission merely to propagandize?

Last Friday, Antarctica set its coldest EVER March temperature…

…somehow, in what we’re to believe is a linearly warming world on the brink of “overheating”, the world’s southernmost continent is currently the coldest its ever been for the time of year.

The Vostok Station clocked a bone-chilling -75.3C (-103.54F) on the morning of Friday, March 20, as spotted by @TempGlobal on Twitter:

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Location of Vostok (Wiki).

Continuer la lecture de ANTARCTICA JUST SET ITS COLDEST MARCH TEMPERATURE ON RECORD: A “GLOBAL WARMING” DESTROYING -75.3C (-103.5F) →

climate-debate

New research first to relate Antarctic sea ice melt to weather change in tropics

by C. Rotter, March 16, 2020 in WUWT

Diminishing sea ice translates to warmer ocean, more rain, and stronger trade winds.
University of California – San Diego

Arctic and Antarctic ice loss will account for about one-fifth of the warming that is projected to happen in the tropics, according to a new study led by Mark England, a polar climate scientist at Scripps Institution of Oceanography at the University of California San Diego, and Lorenzo Polvani, the Maurice Ewing and J. Lamar Worzel Professor of Geophysics at Columbia Engineering, England’s doctoral supervisor.

While there is a growing body of research showing how the loss of Arctic sea ice affects other parts of the planet, this study is the first to also consider the long-range effect of Antarctic sea ice melt, the research team said.

“We think this is a game-changer as it shows that ice loss at both poles is crucial to understanding future tropical climate change,” England said of the study funded by NASA and the National Science Foundation. “Our study will open a hitherto unexplored direction and motivate the science community to study the large effects that Antarctic sea ice loss will have on the climate system.”

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Les glaces terrestres, la cryosphère (1/3)

by J.C. Maurin, 13 mars 2020 in ScienceClimatEnergie

On désigne par cryosphère l’ensemble des glaces terrestres. Son évolution, lors des dernières décennies, est souvent présentée comme préoccupante: il en résulterait une forte hausse des niveaux marins et un changement d’albédo et donc du bilan énergétique de la Terre. Cette première partie de l’article présentera quelques ordres de grandeurs pour les glaces terrestres.
On utilisera principalement les données du chapitre 4 du rapport AR5 WG1 (5th Assessment Report, Working Group 1) qui a été publié en 2013 par l’organisme intergouvernemental GIEC.

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4. Conclusions

  • La cryosphère c’est en premier lieu les zones proches du pôle Sud : banquises et glaciers ne représentent ensemble que 0,7% du volume de la cryosphère alors que la seule partie Est de l’Antarctique, bien moins connue, représente plus de 75% de la cryosphère, soit 107 fois plus.
  • La simple correction du volume de glace en Antarctique, entre les rapports du GIEC AR4 (2007) et AR5 (2013), est 4 fois plus grande que le volume (Banquises + Glaciers).
  • Les variations actuelles de la cryosphère restent négligeables si on les compare à celles du passé : l’ensemble des glaces terrestres, il y a 20 millénaires, devait avoir un volume au moins double du volume actuel. En effet, la fonte des glaces (entre -18 ka et -8 ka) fait monter le niveau des océans de ≈ 120 m  contre 66 m SLE (Sea Level Equivalent à la Figure 1).

La deuxième partie de l’article (2/3) commentera les choix rédactionnels du GIEC pour le chapitre 4 de l’AR5 et donnera des ordres de grandeurs complémentaires pour les banquises et les glaciers.