Archives par mot-clé : Antarctica

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

Medieval Warm Period Undeniable, Pronounced In Antarctica And Poland, 2 New Studies Show

by P. Gosselin, Mar 9, 2025 in NoTricksZone 

Natural cycles drive our climate

The latest video by the Germany-based European Institute for Climate and Energy (EIKE) looks at CO2 and the troublesome Medieval Warm Period, which has long been a thorn for climate alarmists.

Hat-tip: Klimanachrichten

The Medieval Warm Period, the natural warm phase between 700 and 1300 AD, cannot be reproduced climate models because the simulations react primarily to CO2. Back then CO2 was not a factor because its concentration level in the atmosphere was pretty much constant. That’s why people would rather keep the Medieval Warm Period quiet.

But the facts speak for themselves. Two studies now add further pieces to our knowledge of the medieval climate.

Antarctica

In October 2023, a paper by a team of researchers led by Zhangqin Zheng from the University of Science and Technology of China in Hefei was published in the journal Quaternary Science Reviews. It deals with historical changes in the Adélie penguin population in the Ross Sea region of Antarctica and their climatic influences.

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These natural processes are still taking place today and have by no means ended with the start of the CO2 increase.

Poland

The other study comes from Poland. The research group led by Rajmund Przybylak from Nicolaus Copernicus University in Toruń, Poland, published their work in the journal “Climate of the Past” in November 2023. The article presents current findings on climate change in Poland for the period from 1000 to 1500 AD. This period also includes the Medieval Warm Period. The scientists first studied all available quantitative climate reconstructions that have been produced for Poland in the last two decades. They also produced four new reconstructions using three dendrochronological series and an extensive database of historical source data on weather conditions. The growth of conifers in the lowlands and mountains of Poland depends on the temperatures in the cold season, especially in February and March. All available reconstructions based on dendrochronological data refer to this time of the year. Summer temperatures were reconstructed using biological proxies and documentary evidence. However, the latter are limited to the 15th century. The winter temperature was used as a proxy for the annual temperature proxies, instead of the usual use of the summer temperature.

The Medieval Warm Period probably occurred in Poland from the late 12th century to the first half of the 14th or 15th century. All analyzed quantitative reconstructions indicate that the Medieval Warm Period in Poland was comparable or even warmer than the average temperature in the period 1951-2000.

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unclassified

Surveys Show Vast Bulk of Antarctica Is Stable or Growing

by  H.S. Sterling, June. 16, 2024 in WUWT

We hear a lot in the mainstream media about massive ice loss in Antarctica and how it may radically increase sea level rise. The West Antarctic ice sheet and ice on the Antarctic peninsula are in decline, with some massive glaciers threatening to break off; however, conditions there are not the same as for the vast bulk of the continent. First, the subsurface geothermal/volcanic activity that is driving much of the melting in West Antarctica is not affecting the vast bulk of the continent. And the shifting ocean oscillations, which affect the continent’s climate as a whole, have a much greater, more direct impact on the Antarctic peninsula, the northern-most part of the continent, a relatively narrow spit of land surrounded by oceans and beset be clashing currents.

The conditions of the sea ice around Antarctica don’t matter in the sea level equation. Sea ice changes dramatically each season, waxing and waning with the seasons and the currents. For the limited period for which we have consistent measurements, Antarctica’s sea ice has set new records for extent and for low levels during the most recent period of climate change. Neither, however, impact sea levels since floating ice doesn’t displace water.

NASA reported in 2015 that because East Antarctica, which makes up the bulk of the continent, was adding ice and snow, Antarctica as whole may, in fact, be gaining ice on net, implying it could be modestly taking away from sea level rise rather than adding to it. At least from 1992 to 2015, when the report was published.

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climate-debate, Cooling

Significant West Antarctic Cooling in the Past Two Decades Driven by Tropical Pacific Forcing

by X. Zhang et al., 2023, Apt 30, 2024  in BullAmerMeterologicalSoc

Abstract

During the second half of the twentieth century, the West Antarctic Ice Sheet (WAIS) has undergone significant warming at more than twice the global mean and thus is regarded as one of the most rapidly warming regions on Earth. However, a reversal of this trend was observed in the 1990s, resulting in regional cooling. In particular, during 1999–2018, the observed annual average surface air temperature had decreased at a statistically significant rate, with the strongest cooling in austral spring. The spring cooling correlates significantly with the second leading modes (EOF2) derived from empirical orthogonal function (EOF) analysis on the sea level pressure over Antarctica during 1999–2018, associated with the negative phase of the interdecadal Pacific oscillation with an average of cooling of central and eastern tropical Pacific surface sea temperature (SST) anomalies. The EOF2 results in the enhanced cold southerly winds on the continental WAIS through the cyclonic conditions over the Amundsen Sea region and a blocking high in the Drake Passage and northern Antarctic Peninsula, causing the WAIS cooling trend.

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climate-debate

Antarctica Is Colder, Icier Now Than Any Time In 5000 Years. The Last Warm Period Was 1000 Years Ago.

by K. Richard, Apr 15, 2024 in NoTricksZone

More evidence emerges that Antarctica has undergone rapid glacier and sea ice expansion in recent centuries, in line with the long-term and recent Antarctic cooling trend.

West Antarctica’s mean annual surface temperatures cooled by more than -1.8°C (-0.93°C per decade) from 1999-2018 (Zhang et al., 2023).

Not just West Antarctica, but most of the continent also has cooled by more than 1°C in the 21st century. See, for example, the ~1°C per decade cooling trend for East Antarctica (2000 to 2018) shown in Fig. ES

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According to a new study, about 6000 years ago Antarctica’s Collins Glacier’s frontline was a full 1 km southwest of its current extent. The frontline advanced to today’s extent ~5000 years ago.

“Previous studies proposed that 6000 yr BP, the frontline position of the Collins Glacier was located 1 km further south west than the present, and that the current frontline was first attained at approximately 5000 yr BP.”

The glacier then continuously retreated south of the modern extent for another 4000 years, with peak ice loss 1000 years ago (as shown in the 1000-year “Proglacial lake environment” image). In the last 1000 years this glacier has rapidly re-advanced back to the glaciated extent from 5000 years ago, which is in line with the sustained cooling trend ongoing since the Medieval Warm Period.

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climate-debate

No, CNN, Climate Change Is Not Driving Doomsday Glacier’s Decline

by S. Burnett, Mar 5, 2024 in ClimateChangeDispatch

A CNN story implies that supposed human-caused climate change is causing the Thwaites Glacier to melt, causing sea level rise. This is false.

Data show that Antarctica has not been warming. Also, the study CNN cited itself shows the glacier has declined dramatically and recovered repeatedly in the past, all without human contribution, suggesting the present decline is part of a natural cycle. [emphasis, links added]

At approximately the size of Florida, the Thwaites Glacier is the broadest glacier on Earth. The Thwaites Glacier is often referred to as the “Doomsday Glacier,” based on the belief that a complete collapse would cause as much as two feet of sea level rise over time.

The CNN story, “The ‘Doomsday Glacier’ is rapidly melting. Scientists now have evidence for when it started and why,” discusses a new study published in the journal Proceedings of the National Academy of Sciences, which determined when the present decline began.

“By analyzing marine sediment cores extracted from beneath the ocean floor, researchers found the glacier began to significantly retreat in the 1940s, likely kicked off by a very strong El Niño event — a natural climate fluctuation which tends to have a warming impact,” reports CNN.

“Since then, the glacier has been unable to recover, which may reflect the increasing impact of human-caused global warming, according to the report.”

Although the commencement of … Thwaites’ decline may now have been determined, any prognostications about future trends for the glacier are pure speculation, unsupported by historical evidence or data about present Antarctic trend.

The underlying reports determined that the Thwaites glacier’s decline commenced in the 1940s probably prompted by a powerful El Nino event that warmed the abutting waters.

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better to know...?, climate-debate

Antarctic Sea Ice Volume Greater Than The Early 1980s

by P. Homewood, Dec 21, 2023 in NotaLotof PeopleKnowThat

There was much scaremongering from the alarmist community when Antarctic sea ice extent fell earlier in the year. As the Antarctic summer begins, the melt has slowed down, to the extent that extent is not even the lowest since 1979, and it is higher than in 2017:

 

https://zacklabe.files.wordpress.com/2023/12/nsidc_sie_ant_lines-5.png

https://zacklabe.com/antarctic-sea-ice-extentconcentration/

But much more important is the fact that sea ice volume remains higher than the early 1980s, thanks to the fact that it is much thicker than normal around the peninsula:

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climate-debate

New Study: Antarctic Sea Ice Completed Half Its Deglacial Retreat 1000s Of Years Before CO2 Began Rising

by K. Richard, Nov 16, 2023 in NotricksZone

The timing of the dramatic Antarctic sea ice decline during the last deglaciation suggests solar forcing and sea ice retreat “instigated” century-scale climate warming and atmospheric CO2 change. This would appear to challenge the perception CO2 plays a causal role in glacial-interglacial sea ice and climate changes.

From ~21,000 to 19,500 years ago, when CO2 was thought to have been at its lowest point in the Quaternary ice age (~180 ppm), the sea ice surrounding East and West Antarctica completed 50% of its eventual deglaciation-era decline (Sadatzki et al., 2023).

“[I]ndependent lines of evidence supporting that early sea ice and surface ocean changes in the Southern Ocean initiated as early as ~19.5 ka ago (with signs of summer sea ice retreat in our reconstruction as early as ~21 ka ago) and thus (at least) about 2 ka before major deglacial changes in global ocean circulation, climate, and atmospheric CO2.”

The increase in 65°S insolation during these millennia was deemed sufficient to drive this magnitude of sea ice retreat.

“This early increase in local integrated summer insolation at 65°S, which is independent of the longitude, may have thus provided enough energy to initiate melting of the near-perennial sea ice cover in late glacial.”

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climate-debate, Cooling

New Study Finds Most Of Antarctica Has Cooled By Over 1°C Since 1999…W. Antarctica Cooled 1.8°C

by K. Richard, Nov 6, 2023 in NoTricksZone

Significant 21st century cooling in the Central Pacific, Eastern Pacific, and nearly all of Antarctica “implies substantial uncertainties in future temperature projections of CMIP6 models.” – Zhang et al., 2023

New research indicates West Antarctica’s mean annual surface temperatures cooled by more than -1.8°C (-0.93°C per decade) from 1999-2018. In spring, the West Antarctic Ice Sheet (WAIS) cooling rate reached -1.84°C per decade.

Not only has the WAIS undergone significant cooling in the last two decades, most of the continent also cooled by more than 1°C. See, for example, the ~1°C per decade cooling trend for East Antarctica (2000 to 2018) shown in Fig. ES1.

Of 28 CMIP6 models, none captured a cooling trend – especially of this amplitude – for this region. This modeling failure “implies substantial uncertainties in future temperature projections of CMIP6 models.

 

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The post-1999 cooling trend has not just been confined to Antarctica. Sea surface temperatures (SSTs) in the Eastern and Central Pacific (south of 25°N) also cooled from 1999-2018 relative to 1979-1997. This cooling encompasses nearly half of the Southern Hemisphere’s SSTs.

climate-debate

Satellite Data Shows Antarctica Continues Adding Ice Mass, Lowering Sea Level

by Dr. M. Wielicki, Oct 19 2023 in Climate ChangeDispatch

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Antarctica presented a more complex picture. While the continent as a whole lost about 130 gigatons of ice each year during a similar timeframe, the loss was most pronounced in West Antarctica, especially around the Amundsen Sea sector.

This accelerated melting in West Antarctica is a matter of particular concern for researchers, as it is claimed to have the potential to destabilize larger sections of the Antarctic ice sheet, leading to more pronounced sea-level rise in the future.

Mass change of the Antarctic Ice Sheet from April 2002 to September 2020. Time series of mass change from the GRACE and GRACE-FO missions, M(t), for the entire Antarctic Ice Sheet (green) and its division into East Antarctica (blue), West Antarctica (red), and the Antarctic Peninsula (yellow). The vertical lines indicate the end of the GRACE and the beginning of the GRACE-FO monthly data availability (June 2017 and July 2018, respectively). Shadings represent 1-σuncertainties. Equivalent sea-level contribution (right axis) is approximated as 1 mm sea-level rise for 360 Gt of ice mass loss. Source

However, since early 2020, nearly 1,000 gigatons of ice have been added to Antarctica. This remarkable ice gain represents nearly one-third of the total ice loss since 2002.

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