Hidden Antarctic Lake Drains 78 Million Cubic Meters, Causing Ice Surface to Sink 6 Meters

Researchers using satellite data have documented the drainage of the Kronshtadskiy (also spelled Kroushtadskiy) subglacial lake in East Antarctica near the Amery Ice Shelf, which caused a broad depression in the overlying ice surface that deepened by more than 6 meters (about 20- 21 feet) at its center.

Double- Differential Interferometric Synthetic Aperture Radar (DDInSAR) is an advanced remote- sensing technique that measures subtle, time- varying vertical surface displacements, especially useful for detecting activity of subglacial lakes under Antarctic ice sheets.

A circular depression in the icy surface of Antarctica, indicating a drained lake that caused the ice to sink by 6 meters.
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Researchers using satellite data have documented the drainage of the Kronshtadskiy (also spelled Kroushtadskiy) subglacial lake in East Antarctica near the Amery Ice Shelf, which caused a broad depression in the overlying ice surface that deepened by more than 6 meters (about 20- 21 feet) at its center.

The lake, previously hidden under the ice, lost an estimated 78 million cubic meters (roughly 20.6 billion gallons) of water between 2016 and 2021. This volume is equivalent to tens of thousands of Olympic- sized swimming pools. The affected surface area was roughly circular and covered about 61 square kilometers (24 square miles). Average surface lowering across the area was about 1.3 meters (4.3 feet).

Key details from the study (published in Scientific Reports by Jihyun Moon and Hoonyol Lee of Kangwon National University, South Korea):

  • Most drainage happened early: the center sank about 3.8 meters (12.5 feet) in 2016- 2017, then slowed markedly (to under 0.3 meters per year by 2019–2021), with little evidence of major refilling. This pattern points to prolonged or repeated partial drainage through subglacial channels rather than one sudden catastrophic outburst.⁠
  • Analysis relied primarily on Sentinel-1 SAR (synthetic aperture radar) interferometry, which detects millimeter- scale surface changes from space, supported by CryoSat- 2 and ICESat- 2 altimetry data.
  • Downstream surface features (one rising, another sinking) suggest the water may have moved into a connected network of other subglacial reservoirs rather than simply vanishing.⁠

Subglacial lakes form from meltwater generated by geothermal heat and friction at the ice- bedrock interface.

Active ones fill and drain over months to years, influencing ice- sheet flow by lubricating the base and potentially affecting how ice reaches the ocean. This event adds to growing satellite- based inventories of such lakes (hundreds are now known across Antarctica) and helps map hidden hydrologic networks.

The findings highlight how remote sensing can reveal dynamic processes under kilometers of ice that would otherwise be inaccessible.

Map of the Amery Ice Shelf and surrounding basins, showing ice velocity with a color gradient from blue (0 m/year) to red (1300 m/year), along with labeled features such as Fisher Basin, Mellor Basin, and Kroshatdatskiy subglacial lake.
The area of the Sentinel-1 SAR IW images shown in descending orbit (yellow box) and the processed image area in this study (red box) over the ice velocity map. Kronshtadskiy subglacial lake, the target of this study, is inside the red box. Credit: Scientific Reports (2026). DOI: 10.1038/s41598-026-75829-x

Double- Differential Interferometric Synthetic Aperture Radar (DDInSAR) is an advanced remote- sensing technique that measures subtle, time- varying vertical surface displacements, especially useful for detecting activity of subglacial lakes under Antarctic ice sheets.

How it builds on standard InSAR methods

TechniqueWhat it doesMain signal isolated
InSARCompares the radar phase of two SAR images of the same area acquired at different times (or slightly different positions)Topography, surface motion, atmosphere and noise
DInSAR (Differential InSAR)Removes the topographic contribution (using a DEM or a second interferometric pair)Surface deformation (line- of- sight), which still mixes horizontal ice flow and vertical changes
DDInSAR (Double-Differential InSAR)Differentiates two DInSAR interferograms from different time periodsTemporally varying vertical displacement (the steady horizontal ice- flow component largely cancels out)

Why DDInSAR is needed on ice sheets

On fast- flowing Antarctic glaciers, the dominant signal in a normal DInSAR interferogram is the steady horizontal ice motion. Subglacial lake filling or drainage produces a much smaller vertical (up and down) signal that is mixed in with the flow.

If ice- flow velocity is approximately constant between the two periods, subtracting one DInSAR interferogram from another cancels the common flow contribution. What remains are closed contour “fringes” that map the change in vertical displacement rate, exactly the signature of a lake rising or falling.

Practical application (as used for Kronshtadskiy lake)

  • Researchers form many short- baseline (e.g., 24-day) Sentinel- 1 DInSAR pairs.
  • They then create DDInSAR interferograms by differencing pairs from different epochs.
  • The resulting maps reveal a roughly circular zone of progressive surface sinking (up to ~6.4 m at the center over several years), from which water- volume loss can be estimated.
  • Complementary ascending and descending orbits or altimetry (CryoSat- 2, ICESat- 2) can further separate residual horizontal- flow variations if needed.

Advantages and limitations

  • Strengths: High spatial resolution, sensitivity to millimeter- to- centimeter vertical changes, works through cloud and polar night, and can detect relatively small or short- lived hydrological events that altimetry alone might miss.
  • Assumptions: Ice- flow velocity must be reasonably steady; otherwise, residual flow- variation signals must be modeled and removed.
  • Coherence: Requires sufficient radar coherence (surface stability) between acquisitions; long temporal baselines or heavily crevassed ice can degrade results.

In short, DDInSAR is a clever “double differencing” of radar phase measurements that isolates the vertical “breathing” of the ice surface caused by hidden subglacial water movement.

A colorful satellite image showing polar topography, with labeled tracks from ICESat and ICESat-2. Multiple geographic markers are present, including points labeled A, B, and C, along with areas outlined in white and red.
Ground tracks of satellite altimeters. The white polygon is the boundary of the subglacial lakes defined by DDInSAR while the black polygon is the boundary of Kronshtadskiy subglacial lake. Credit: Scientific Reports (2026). DOI: 10.1038/s41598-026-75829-x

Drainage of Kronshtadskiy subglacial lake in Antarctica observed by double-differential SAR interferometry

Abstract summary

Hundreds of subglacial lakes in Antarctica have been identified via radio- echo sounding and satellite altimetry but detecting smaller or shorter- lived hydrological events has been difficult because of limited spatial and temporal resolution. This study applied Double- Differential Interferometric Synthetic Aperture Radar (DDInSAR) to measure surface- elevation changes linked to the Kronshtadskiy subglacial lake near the Amery Ice Shelf in East Antarctica.

Researchers generated 77 DDInSAR interferograms from Sentinel- 1 SAR images (24- day temporal baseline) spanning 2016- 2021. They documented a rapid drainage event at a roughly circular subglacial lake covering 61 km². Estimated water- volume loss was 78.0 million cubic meters (Mm³).

  • Maximum subsidence at the lake center: 6.37 m.
  • Most of the drop occurred in 2016– 2017 (rate ≈ 2.54 m/yr).
  • Rates then declined sharply: 0.88 m/yr in 2018 and < 0.30 m/yr during 2019–2021.

Independent satellite altimetry from CryoSat-2 and ICESat-2 confirmed the overall subsidence trend. The work shows that DDInSAR is effective for monitoring subglacial hydrology even in fast- flowing polar ice environments.

Additional details from the page

  • Funding: National Research Foundation of Korea and related Korean technology programs.
  • Corresponding author: Hoonyol Lee (hoonyol@kangwon.ac.kr).
  • Open-access under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 license.
  • Received 7 April 2026; accepted 9 October 2026.

This is the primary peer- reviewed source behind the recent news reports about the “sinking Antarctic ice” and the lake’s water loss.

The DDInSAR method provided higher- resolution spatial mapping of the surface depression than altimetry alone, allowing the volume estimate and the temporal evolution of the drainage to be reconstructed in detail.

Journal: Scientific Reports, (2026), Open access

DOI: 10.1038/s41598-026-75829-x

Published: 12 October 2026 (early access, accepted version)

Authors: Jihyun Moon & Hoonyol Lee

Map of Antarctica showing subglacial lakes. Red triangles indicate newly discovered active subglacial lakes, pink triangles represent existing archive active subglacial lakes, and black circles denote existing archive stable subglacial lakes. Key locations and ice shelves are labeled.
Updated Antarctic subglacial lake inventory. Credit: Nature Communications (2025). DOI: 10.1038/s41467-025-63773-9. https://www.nature.com/articles/s41467-025-63773-9

Global Warming Halted the Next Ice Age Just as It Began

A new study published in Science (October 22, 2026) by researchers including Nicolás Young and Joerg Schaefer of Columbia’s Lamont- Doherty Earth Observatory (part of the Columbia Climate School) finds that the last remnant of the Laurentide Ice Sheet began expanding about 2,000 years ago, potentially marking the start of the next glacial period, but reversed and began retreating around 1960 due to rising temperatures linked to human- caused warming.

After shrinking through much of the early- and mid- Holocene, the LIS began growing again around 2000 years ago but started shrinking once more around 1960. The authors attribute this reversal to anthropogenic greenhouse forcing and present it as evidence that humans caused the termination of the next glaciation.

Infographic titled 'Global Warming Halted the Next Ice Age Just as It Began' explaining the paradox of climate change. It summarizes global warming, the natural cooling trend leading to the next ice age, and the human intervention that prevented it. Includes data on CO2 levels and global temperatures, emphasizing the precarious balance in climate management.
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A new study published in Science (October 22, 2026) by researchers including Nicolás Young and Joerg Schaefer of Columbia’s Lamont- Doherty Earth Observatory (part of the Columbia Climate School) finds that the last remnant of the Laurentide Ice Sheet began expanding about 2,000 years ago, potentially marking the start of the next glacial period, but reversed and began retreating around 1960 due to rising temperatures linked to human- caused warming.

The Barnes Ice Cap on Baffin Island (Nunavut, Canada), roughly the size of Delaware and the final surviving piece of the vast Laurentide Ice Sheet that once covered much of Canada and parts of the northern United States, reached a minimum size after about 3,600 years ago.

It then began re- expanding around 2,000 years ago as the climate cooled enough for net ice accumulation. The researchers interpret this renewed growth as the onset of the next glaciation (what is commonly called an “ice age”), even though a full continental- scale ice sheet would have taken many thousands of years (on the order of ~30,000 years) to rebuild.

Key methods and evidence

  • The ice is frozen to the bedrock (not sliding), which preserved vegetation (mosses, lichen, etc.) that was overrun and killed as the ice advanced. Carbon-14 dating of these plants, combined with data from other nearby ice caps and exposure dating (e.g., beryllium-10 on rocks), allowed reconstruction of the ice-margin timeline.
  • Historic aerial photos and observations show the ice reached a recent maximum around 1960 and has since retreated (margins averaging ~4 meters per year in recent decades), as summer melt began exceeding winter accumulation.⁠

This challenges model- based views that the next glacial inception was still thousands or tens of thousands of years away under natural (Milankovitch orbital) conditions. The team argues the first renewed ice- sheet growth should count as the beginning of a glacial period. The findings also provide retrospective context for 1970s scientific concerns about a coming ice age: the process had in fact begun, though it would have been gradual and not immediately noticeable.

The paper (“Late Holocene reexpansion of the Laurentide Ice Sheet”) attributes the post- 1960 reversal primarily to anthropogenic greenhouse- gas forcing overwhelming the natural cooling trend from declining summer insolation.

Models suggest the Barnes Ice Cap will disappear entirely within the next few centuries, removing a key nucleation point that historically helped ice sheets expand during cooling phases. Future glacial cycles, if they occur under elevated greenhouse-gas levels, may therefore unfold differently.

In short, the study presents observational evidence that human- driven warming interrupted an emerging glacial period that had already begun in the Arctic remnant of the last major North American ice sheet.

Map showing the Baffin Bay area with labeled features including the Barnes Ice Cap, locations of ice cores, and significant geological data points. Information is illustrated with various symbols and numerical data indicating estimated ages.
Areal extent of the North American Ice Sheet Complex at the Last Glacial Maximum ~22 ka calibrated BP (42)
Late Holocene reexpansion of the Laurentide Ice Sheet | Science

Editor’s summary

Has anthropogenic warming prevented the next glacial cycle? Young et al. examined the Barnes Ice Cap (Baffin Island, Canada), the last remaining piece of the Laurentide Ice Sheet (LIS), once the largest Pleistocene ice sheet covering much of North America.

After shrinking through much of the early- and mid- Holocene, the LIS began growing again around 2000 years ago but started shrinking once more around 1960. The authors attribute this reversal to anthropogenic greenhouse forcing and present it as evidence that humans caused the termination of the next glaciation.

Abstract (key points)

  • During interglacials, the Laurentide Ice Sheet retreats to Arctic Canada and reaches a minimum configuration. Its subsequent reexpansion marks the start of the next glaciation.
  • The Barnes Ice Cap (the last remnant of the most recent LIS) reached its minimum interglacial size after ~3.6 thousand years ago.
  • It then reexpanded beginning ~2000 years ago, which the authors interpret as the onset of the next glaciation.
  • This renewed LIS reached maximum dimensions around 1960 CE.
  • After that, anthropogenic summer warming produced a negative mass balance, ice-margin recession, and the termination of the next glaciation.
  • This occurred despite ongoing natural decline in summer insolation, illustrating the dominant influence of anomalous greenhouse- gas forcing.

Main findings and methods

The Barnes Ice Cap sits on relatively low- elevation bedrock (~500 m) and is largely cold- based (frozen to its bed), so it preserves rather than erodes underlying vegetation.

Researchers used:

  • In situ ¹⁰Be surface- exposure dating of bedrock and erratics to show the ice margin retreated rapidly across the modern forefield and inside the present-day margin at 3.56 ± 0.24 ka BP.
  • Radiocarbon dating of entombed vegetation (mosses and woody plants) that was overrun and killed as the ice advanced, then re- exposed by recent retreat. These “kill dates” document the timing and progressive advance of the ice margin toward its ~1960 historical maximum (a clear trimline). Many ages cluster around the coldest part of the Little Ice Age (~1800 ± 200 CE).

The regional snowline first intersected the Baffin plateau landscape around the start of the Common Era, allowing net ice accumulation and the beginning of re- expansion. Growth continued (with pulses during cooler intervals) until ~1960, after which summer warming reversed the mass balance. Between ~1960 and 2022 the margin retreated 200- 800 m.

Broader implications

The authors argue that the first renewed growth of the LIS remnant should be counted as the start of the next glacial cycle, even though a full continental-scale ice sheet would have taken many millennia to develop.

The modern reversal, driven by human- caused greenhouse -gas increases, interrupted that process. The Barnes Ice Cap is projected to disappear within the coming centuries, removing a historically important nucleation site for future ice- sheet growth.

A companion Perspective in the same issue of Science (“Has the next ice age already come and gone?” by Shaun A. Marcott) discusses the results in the context of orbital (Milankovitch) cycles and anthropogenic disruption of the glacial- interglacial metronome.⁠

The paper is currently listed as free access on the Science website.

Journal: Science, Vol. 394, Issue 6822, pp. 455–459

DOI: 10.1126/science.aed3379, www.science.org/doi/10.1126/science.aed3379

Provided: Columbia Climate School

Authors: Nicolás E. Young, Joerg M. Schaefer, and colleagues.

Disappearing Hurricanes Leave Disappointed Scientists Without Fuel for Climate Alarm

Hurricanes in the North Atlantic have largely disappeared this year, leaving bitterly disappointed scientists without fuel for their climate alarm and having to admit the role of natural variation, says Chris Morrison.

Until recently the area was heading for a double bagel – zero hurricanes with zero major hurricanes, although a late storm has upset a score line never before seen in the historical record.

But wait, not on this occasion. Simon King from the BBC states that a natural occurring El Niño is the “biggest reason”.

Three scientists standing on a beach, examining data displays regarding hurricane tracking and satellite information.
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From The Daily Sceptic

By Chris Morrison

Hurricanes in the North Atlantic have largely disappeared this year, leaving bitterly disappointed scientists without fuel for their climate alarm and having to admit the role of natural variation, says Chris Morrison.

A serene view of a calm ocean at sunset with gentle waves and a gradient sky transitioning from orange to purple.

Emergency explanations have had to be rushed to the climate catastrophising front following the shocking news that hurricanes in the North Atlantic have largely disappeared this year.

Until recently the area was heading for a double bagel – zero hurricanes with zero major hurricanes, although a late storm has upset a score line never before seen in the historical record. As with all ‘extreme’ outlier weather events, humans must be responsible, at least that has been the mainstream reaction for around 30 years (we have the computer models to prove it). But wait, not on this occasion. Simon King from the BBC states that a natural occurring El Niño is the “biggest reason”.

Wot, no humans altering the climate? Surely a first for the BBC. In fact, lead weather presenter King is on the right track in that the El Niño Southern Oscillation (ENSO), a transporter of heat from the Pacific Ocean around the world, can reduce wind shear and suppress storm activity. But activity is complex in the chaotic, non-linear, largely unmeasurable atmosphere. Such a simple explanation didn’t work well in 2023 when another strong El Niño occurred at a time when there was a long-term-average-busting hurricane season with seven hurricanes and three major hurricanes. Then the narrative-driven media was jammed packed with possible anthropogenic causes.

Long experience of being fed climate claptrap means we must be intrigued when ‘natural’ reasons are suddenly being used to explain the inevitable weather outliers that run the danger of casting doubt on the pseudoscience backing the Net Zero fantasy. While such natural explanations are welcome, indeed almost always highly relevant, they are curiously missing from most useful idiot mainstream climate messaging.

In 2018, Oliver Milman of the Guardian gave us the standard climate slop on extreme storms when he reported: “Hurricane rainfall could increase by a third and wind speeds boosted by up to 25 knots if global warming continues.”

Almost invariably, natural causes for all weather or weather-related events are either missing or entirely lost in proselytising action. For coral showing five years of record growth on the Great Barrier Reef, the largest coral ecosystem in the world – almost no interest in the mainstream media.

Global burned areas in the annual fire season to February 2026 were down 18% on the recent 20-year average – who cares when there is a much better story about Bordeaux claret having a slightly smoky taste this year due to a number of local fires indicative of Fireball Earth. Don’t believe that such a story could appear in the biased press – I give you Esme Stallard’s 2023 BBC classic: ‘Climate change could make beer taste worse.’

A stable Greenland ice sheets this year, maybe a small increase – get in the bin. Surely this is a good news story for all except perhaps makers of scuba diving equipment selling kit for all those grandchildren who are going to be underwater later in the century. A natural explanation, in case it never gets reported, is that the northern 2026 summer jet stream kept high pressure over the UK and Europe, and all the low pressure-induced rain seems to have fallen as snow during a colder Greenland season. In addition, cyclical factors seem to be at play since ice loss in Greenland has been falling for a number of years anyway.

Much of this is caused by, or is called, weather. Explaining that bad or extreme weather is as much a natural event as all other types does not fit the predetermined narrative that drives the population panic required for the hard Left Net Zero project. Just ‘look out of the window’ and complex atmospheric science can be easily understood by blaming all the crap weather on humans using hydrocarbons. Works every time when there are loads of convenient hurricanes – less well when the wind is stilled and the ocean is as calm as a mill pond.

In fact, the constant suggestion that human-caused climate change will lead to more severe tropical hurricanes is not borne out by scientific data. Leaving aside the fact that hurricanes in number and strength have shown little noticeable change for at least a century, the idea that warmer ocean waters caused by higher carbon dioxide levels in the atmosphere are stoking up the storms is highly contentious. In 2023, the tropical Atlantic featured record surface temperatures but a powerful El Niño failed to make much impression on the high number of storms. Ocean temperatures this year were a little cooler but still remained at the third highest level recorded. Did a marginal drop in temperature affect the dramatic turnaround in hurricane numbers? Maybe, maybe not, but it might be an idea to stay off blaming it on humans until more definite answers are found.

In fact, recent scientific evidence suggests that the link between ENSO and tropical storms has changed over recent decades. Last year, a group of US-based Earth scientists found that. in the Atlantic, the link was weak in the 1960s-1970s, strong from the 1980s to early 2000s and a little weaker since then. Other factors determining hurricanes formations were noted to be at play, including higher levels of mid-troposphere humidity and differing phases of important ocean currents.

Chris Morrison is the Daily Sceptic’s Environment Editor. Follow him on X. His new best-selling book is IMPLAUSIBLE: How scientists, activist politicians and journalists invented a climate crisis, weaponised junk computer model findings and claimed a fake consensus to promote the collectivist Net Zero fantasy – out now and currently No. 1 in Amazon paperbacks in Environment and Amazon downloads in Environmental Issues. Only £3.99 for the download and £8.99 for the paperback.

Northern Ice Sheets Cooled the Southern Ocean and Helped Lock Away CO₂ During Ice Ages

New research from the University of St Andrews, published in the Journal of Climate (22 October 2026), proposes a mechanism linking Northern Hemisphere ice sheets to Southern Ocean changes that helped drive past ice ages via CO₂ drawdown.

Milankovitch cycles (also called Milanković cycles) are periodic variations in Earth’s orbital geometry and axial orientation that change the amount and distribution of solar radiation (insolation) reaching different parts of the planet over tens to hundreds of thousands of years.

Diagram illustrating the Ice Age Earth system featuring expanded ice sheets, intensified ocean circulation, and CO2 drawdown processes. Key elements include cold deep currents, deep ocean conveyor pathways, and CO2 absorption and sequestration in the Southern Ocean.
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New research from the University of St Andrews, published in the Journal of Climate (22 October 2026), proposes a mechanism linking Northern Hemisphere ice sheets to Southern Ocean changes that helped drive past ice ages via CO₂ drawdown.

Ice ages are largely driven by more atmospheric CO₂ being stored in the ocean, a process mainly controlled by changes in the Southern Ocean around Antarctica (involving ocean circulation and sea ice).

Orbital cycles (Milankovitch) initiate Northern Hemisphere ice- sheet growth, but the link from those distant northern ice sheets to the Southern Ocean CO₂ sink has been unclear.⁠

The study proposes that growing northern ice sheets cool nearby North Atlantic waters. These cooler waters circulate southward to the Southern Ocean. If the cooling is strong enough, it can trigger circulation and sea- ice changes there that enhance oceanic CO₂ storage.⁠

Researchers tested this with ocean model simulations that cooled only the far northern latitudes (mimicking large ice- sheet effects) versus cooling the entire planet.

Northern- only cooling produced ~74% of the CO₂ drawdown seen in the global- cooling case, supporting the idea that northern cooling can propagate southward and contribute substantially to glacial CO₂ reduction and related ocean features.⁠

Lead author Dr. Madison Shankle (School of Earth and Environmental Science) noted that the work provides evidence of a plausible mechanism connecting Northern Hemisphere ice sheets with Southern Hemisphere Ocean circulation changes leading to CO₂ drawdown, long a challenge in ice- age theory, and demonstrates it in model simulations.⁠

The paper is titled “Isolated Northern Hemisphere Cooling in an Idealized Model Promotes Ocean Carbon Storage and Glacial- like Ocean Features” (DOI: 10.1175/JCLI-D-25-0355.1).

Understanding these natural carbon- cycle processes are relevant for assessing how the Earth system responds to modern anthropogenic CO₂ increases.

Aerial view of cracked ice over blue water with a snowy edge.
Credit: Евгений Шухман from Pexels

Milankovitch cycles (also called Milanković cycles) are periodic variations in Earth’s orbital geometry and axial orientation that change the amount and distribution of solar radiation (insolation) reaching different parts of the planet over tens to hundreds of thousands of years.

These variations are widely accepted as the primary pacemaker of the Pleistocene ice ages (the glacial- interglacial cycles of the last ~2.6 million years).

They are named after the Serbian mathematician and astronomer Milutin Milanković, who calculated them in the early 20th century.

There are three main cycles:

1. Eccentricity (shape of Earth’s orbit)

  • Period: Dominant cycles of ~100,000 years and a longer ~400,000-year cycle.
  • Earth’s orbit around the Sun varies from nearly circular (low eccentricity) to more elliptical (higher eccentricity).
  • Higher eccentricity slightly increases the total annual solar energy Earth receives and, more importantly, amplifies the contrast between perihelion (closest approach to the Sun) and aphelion (farthest point).
  • Effect on climate is relatively modest on its own, but it modulates the strength of the other two cycles.

2. Obliquity (axial tilt)

  • Period: ~41,000 years.
  • Earth’s axial tilt varies between about 22.1° and 24.5° (currently ~23.4°).
  • Greater tilt increases the seasonal contrast (hotter summers and colder winters), especially at high latitudes.
  • Reduced tilt decreases seasonal contrast, making high- latitude summers cooler, conditions favorable for ice -sheet growth because snow and ice are less likely to melt completely in summer.

3. Precession (axial wobble and precession of the equinoxes)

  • Period: Climatic precession has periods of roughly 19,000 and 23,000 years (the axial precession itself is ~26,000 years).
  • Earth “wobbles” on its axis like a spinning top, and the orientation of the orbit also slowly rotates. Together these change the season in which Earth is closest to the Sun (perihelion).
  • Currently, Northern Hemisphere winters occur near perihelion. When perihelion coincides with Northern Hemisphere summer, summers become warmer (and winters milder) in the north, and vice versa.
  • This strongly affects the intensity of seasons in each hemisphere.

Combined effect and link to ice ages

The three cycles interact, producing complex, quasi- periodic changes in the seasonal and latitudinal distribution of sunlight. The most climatically important quantity is usually Northern Hemisphere high- latitude summer insolation. Cool Northern summers allow snow to persist year- round, enabling ice sheets to grow; warm Northern summers promote melting.

These orbital forcings are relatively small in energy terms. Their effects are strongly amplified by feedback in the Earth system, especially:

  • Ice- albedo feedback (more ice reflects more sunlight, further cooling the planet).
  • Changes in atmospheric CO₂ (largely controlled by ocean processes, particularly in the Southern Ocean).
  • Changes in ocean circulation, vegetation, and dust.

This is why the previous research you asked about is relevant: orbital changes initiate Northern Hemisphere ice- sheet growth, and the new work explores one mechanism by which those ice sheets can influence Southern Ocean circulation and CO₂ drawdown, helping drive the planet deeper into a glacial state.

In summary, Milankovitch cycles do not act alone, but they set the timing and pacing of the ice ages by modulating the distribution of sunlight over long timescales.

Isolated Northern Hemisphere Cooling in an Idealized Model Promotes Ocean Carbon Storage and Glacial-like Ocean Features

Using idealized ocean- model simulations, the authors show that cooling only the Northern Hemisphere high latitudes (mimicking the effect of growing Northern Hemisphere ice sheets) is sufficient to drive a large fraction of the ocean carbon storage and Southern Ocean changes characteristic of glacial periods.

In the key experiments:

  • They cooled air temperatures only north of 40°N (roughly 13% of the model surface) to glacial- like values while holding the rest of the planet at pre-industrial conditions.
  • This isolated northern cooling produced ~74% of the CO₂ drawdown (ocean carbon uptake) that occurred in a parallel simulation in which the entire planet was cooled.
  • The northern- only cooling led to an additional ~18.8 billion tonnes of carbon stored in the ocean.

Growing Northern Hemisphere ice sheets cool nearby North Atlantic surface waters. These cooler, denser waters are transported southward via the global overturning circulation.

When the cooling signal reaches the Southern Ocean, it alters circulation and promotes expanded sea ice. These Southern Ocean changes enhance the ocean’s ability to store carbon (through a combination of physical and biological carbon pumps), lowering atmospheric CO₂ and helping push the climate deeper into a glacial state.

This provides a plausible “teleconnection” linking the two classic features of ice ages that are geographically far apart:

  • Orbital (Milankovitch) forcing initiates Northern Hemisphere ice- sheet growth.
  • The Southern Ocean is the main region responsible for glacial- interglacial CO₂ drawdown.

The paper addresses a long- standing gap in ice- age theory: how northern ice sheets, once formed, can influence the distant Southern Ocean processes that store CO₂.

The idealized modeling approach isolates the pure effect of northern cooling and demonstrates that it can generate glacial- like ocean features even without global cooling or other forcings.

The work is consistent with the broader view that orbital cycles set the pacing of ice ages, while feedback involving ice sheets, ocean circulation, sea ice, and the carbon cycle amplify the response.

Note: The full text on the AMS journals site is behind a paywall and login. The details above are drawn from the official press release, the paper’s metadata, and secondary reporting.

For the complete methods, figures, and discussion (including limitations and sensitivity tests), institutional access or the published PDF is required.

Title: Isolated Northern Hemisphere Cooling in an Idealized Model Promotes Ocean Carbon Storage and Glacial-like Ocean Features

Journal: Journal of Climate, Volume 39, Issue 22 (2026)

DOI: 10.1175/JCLI-D-25-0355.1

Provided: University of St Andrews

Authors: Madison G. Shankle (University of St Andrews), with co- authors including Graeme A. MacGilchrist, Andrea Burke, Alice Marzocchi, Malte F. Jansen, and James W. B. Rae.

Abstract

Earth’s past glacial cycles are paced by orbital insolation changes, but internal climate feedbacks modulating atmospheric carbon dioxide (CO2) are necessary to explain the full magnitude of glacial–interglacial climate variability. Identifying such feedbacks and linking them to orbitally paced forcing remains a challenge, impeding a comprehensive understanding of the glacial cycles. Orbital variations, determining the latitudinal distribution and seasonality of insolation, are primarily important for allowing the buildup of large Northern Hemisphere ice sheets. Meanwhile, the processes canonically understood to drive CO2 drawdown and mediate ocean–atmosphere carbon partitioning are largely hosted in the far-flung Southern Ocean. This study explores the role of remote Northern Hemisphere temperature forcing in influencing Southern Ocean conditions that impact global ocean circulation and carbon content. In a set of idealized ocean–sea ice model simulations, we find that cooling air temperatures to glacial-like levels at the high northern latitudes (emulating the thermal effect of a large Northern Hemisphere ice sheet) drives a substantial CO2 drawdown of 32 ppm—or 74% the magnitude of a simulation forced by globally glacial-like temperatures everywhere (43 ppm). Northern cooling is found to cool not only northern-sourced middepth waters but ultimately also global deep waters, resulting in a strong solubility-driven CO2 drawdown component. It also drives several characteristic features of glacial periods, including expanded southern sea ice and a colder, saltier, and better stratified deep ocean, which contributes to air–sea CO2 disequilibrium. These results demonstrate an interhemispheric connection between Northern Hemisphere conditions paced by orbital variations and Southern Hemisphere processes that modulate deep-ocean carbon content.

No, New York Times, California’s Climate Has Always Been a Land of Flood, Drought, and Fire

The New York Times article “Latest Climate Report Warns of Major Upheaval to California Way of Life” by Soumya Karlamangla, claims California faces a future of bigger storms, more extreme floods, longer droughts, destructive wildfires, disappearing snowpack, and major disruption to everyday life because of climate change. This is highly misleading if not outright false.

It then warns of “more wildfires, bigger storms, longer droughts,” claiming California faces “major upheaval to long-established ways of life.”

Those are dramatic predictions. What the Times largely fails to provide is the historical context necessary to understand them.

A dramatic landscape showing a dry, cracked earth in the foreground, with a backdrop of mountains and dark, stormy skies. The image also depicts a wildfire burning in the distance, representing California's climate challenges.
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From ClimateRealism

By Anthony Watts

Historic illustration depicting K Street in Sacramento during the 1862 flood, showing people in boats navigating through a flooded street lined with buildings.

The New York Times article “Latest Climate Report Warns of Major Upheaval to California Way of Life” by Soumya Karlamangla, claims California faces a future of bigger storms, more extreme floods, longer droughts, destructive wildfires, disappearing snowpack, and major disruption to everyday life because of climate change. This is highly misleading if not outright false. The historical and observational record shows that extreme storms, catastrophic floods, prolonged droughts, enormous wildfires, highly variable snowpack, and coastal erosion have always been defining features of California’s natural environment, while many of the Times’ most alarming claims are projections from climate models rather than observed trends.

The Times opens with a confident description of California’s future:

“Floods will become more widespread and extreme.”

It then warns of “more wildfires, bigger storms, longer droughts,” claiming California faces “major upheaval to long-established ways of life.”

Those are dramatic predictions. What the Times largely fails to provide is the historical context necessary to understand them.

California has always been a land of meteorological extremes. Its Mediterranean climate naturally produces long dry periods punctuated by episodes of tremendous precipitation. Atmospheric rivers carrying Pacific moisture into the state are not a recent creation of climate change. They are fundamental to California’s hydrology.

Perhaps the most obvious omission from the Times article is the Great Flood of 1861-1862.

Historical illustration of K Street in Sacramento during the 1862 flood, depicting boats navigating through submerged streets lined with buildings.
Image courtesy of US Geological Survey.

According to the United States Geological Survey’s history of California storms and floods, a succession of powerful storms battered California for weeks. Rivers overflowed, levees failed, Sacramento flooded, and enormous portions of the Central Valley disappeared beneath water. The USGS describes the event as remaining “unparalleled in its magnitude.”

The storm sequence lasted approximately 45 days. The Sacramento Valley became an inland sea. The flooding was so severe that California lost roughly one-third of its taxable land, and Governor Leland Stanford reportedly traveled by rowboat to his inauguration.

This happened in 1861 and 1862, when atmospheric carbon dioxide concentrations were far below today’s levels. Even that disaster wasn’t unprecedented.

The USGS ARkStorm project reports geological evidence of six megastorms larger than the 1861-1862 event during the past 1,800 years. The agency explicitly states that the Great Flood “is not a freak event,” and that there is no reason similar events will not happen again.

Another USGS review concludes that truly massive rainfall-driven California floods appear in the geological record roughly every 200 years.

That is rather important context when the New York Times tells readers that future extreme flooding represents a newly emerging climate threat.

The same applies to atmospheric rivers. The USGS calls them California’s primary storm mechanism and notes that just a few large atmospheric river events can determine whether a particular year is wet or dry. Researchers are studying sediment records precisely because the approximately 70-year instrumental record of atmospheric rivers is far too short to describe the full range of natural variability.

Climate change may alter the intensity of future atmospheric rivers. The USGS and climate-model studies project that possibility, and it should not be dismissed. But a projection of future change is not evidence that California historically lacked catastrophic atmospheric-river storms.

It plainly did not.

This is also why the Times’ presentation of flooding is so incomplete. Climate Realism has previously documented that major California flooding long predates modern warming, including the 1862 catastrophe and evidence of still larger prehistoric events.

More importantly, the observational precipitation record does not resemble the steadily worsening picture implied by the Times.

The National Oceanic and Atmospheric Administration’s California State Climate Summary shows enormous year-to-year variation in winter precipitation since the late 19th century. Its record of two-inch extreme precipitation events since 1930 likewise shows substantial variability rather than a simple upward march toward ever more extreme rainfall.

The Climate at a Glance California State Climate Summary, using NOAA data, similarly reports little overall change in California’s average annual precipitation since 1900 and no sustained increase in extreme precipitation events.

California’s drought history is equally inconvenient for the Times’ narrative.

NOAA’s reconstructed Palmer Drought Severity Index, seen in the figure below, extends California drought history back approximately 1,000 years using tree-ring and other proxy evidence. It shows repeated prolonged wet and dry periods centuries before industrialization.

Line graph showing the California Palmer Drought Severity Index over time from 1000 to 2000, with values ranging from -8 to 8. The graph features blue bars indicating wet periods and red bars indicating dry periods, along with a black trend line.

California does not alternate between drought and deluge because its climate has suddenly become unstable. Alternating between drought and deluge is normal for California’s climate.

Climate Realism recently made precisely this point in response to similar claims about Highway 1: California’s pattern of drought followed by heavy precipitation is not historically unusual. Massive swings between flooding and drought have occurred for as long as historical and paleoclimate records allow us to examine.

Wildfires deserve the same historical perspective.

The Times tells readers that several destructive fires have occurred during the past decade and presents them as evidence of the trends Californians are supposedly beginning to experience.

But “destructive” is not synonymous with “climatically unprecedented.” Put millions more people, homes, power lines, roads, businesses, and expensive property into fire-prone landscapes, and the economic consequences of fires can increase even without a corresponding increase in the underlying natural hazard.

Fire itself is not an aberration in California. It is an integral part of the landscape.

A peer-reviewed study in Forest Ecology and Management estimated that approximately 1.8 million hectares, about 4.4 million acres, burned annually in prehistoric California before 1800. The researchers concluded that California’s skies were probably smoky through much of the summer and fall long before modern industrial emissions.

California’s own Fish & Wildlife agencies acknowledge the same history, explaining that the state’s ecosystems evolved with fire and citing estimates of approximately 4.4 million acres burned annually before 1800 through lightning and Native American burning.

Climate at a Glance reports that modern California wildfire counts and acreage do not show the simple steadily increasing pattern often implied by climate coverage, while emphasizing the importance of vegetation management, ignition sources, and California’s naturally fire-adapted ecosystems.

None of this means temperature and moisture have no influence on fire behavior. Of course they do. It means that portraying California wildfire as some novel product of modern climate change requires ignoring thousands of years of California fire ecology.

Then there is snowpack. The Times states that Sierra Nevada snowpack is projected to decline 40 percent by midcentury and 60 percent by 2100.

Notice the operative word: projected.

NOAA’s State Climate Summary shows observed Donner Summit snow-water-equivalent record shows tremendous natural variability. April 1 snowpack has ranged from almost nothing to more than 80 inches of water equivalent during the observational period. Record-high values occurred in 1952 and 1983, while extremely low values occurred in 1963, 1988, 2014, and 2015.

The Fifth Climate Change Assessment cited by the Time does not measure California’s snowpack in 2050 or 2100. It cannot. Its future hydrology estimates are produced by feeding downscaled global climate model output into additional hydrological models. California’s own technical documentation describes precisely that modeling chain.

There is nothing illegitimate about using models to explore possible futures. Policymakers need scenarios for planning.

But scenarios are not observations, and newspapers should stop writing about modeled conditions decades from now as though they were measurements already taken.

The Times even acknowledges that the state assessment contains multiple scenarios based on different future greenhouse gas emissions levels, and quotes a state official saying, “The future is not predetermined.” Yet most of the article is written as though it is.

The same problem appears in the claim that as much as three-quarters of California’s beaches “could disappear” by 2100. Latest Climate Report Warns of … Again, “could.”

California’s coastline has been eroding, uplifting, subsiding, sliding, and rearranging itself for millennia. Local relative sea level also varies substantially because California is tectonically active. NOAA tide gauges presently show trends ranging from 5.08 mm per year at North Spit to minus 0.76 mm per year at Crescent City, where the land is rising faster than the ocean. Los Angeles’ long-term gauge shows approximately 1.07 mm per year, equivalent to about 0.35 feet per century if that linear trend continued unchanged.

That is considerably more complicated than “climate change will erase California’s beaches.”

Finally, the Times warns that California agriculture could suffer dramatically, including fruit-yield reductions and less irrigated acreage. Latest Climate Report Warns of … Yet actual agricultural data do not show California agriculture collapsing under recent warming. Climate at a Glance reports, for example, substantial long-term increases in almond production and yields and increased strawberry production.

Again, observations and projections are different things.

California has warmed. Additional warming can affect snow levels, heat extremes, ecosystems, and water management. Those are legitimate subjects for research and prudent planning. But that is a very different proposition from the New York Times’ portrayal of a state approaching some historically unfamiliar climatic upheaval.

California was experiencing catastrophic floods before automobiles existed. It endured megadroughts centuries before coal-fired power plants. Millions of acres burned annually before European settlement. Atmospheric rivers battered the coast long before anyone coined the term “climate change.” Beaches eroded, mountains shed landslides, Sierra snowpack swung wildly from year to year, and Californians learned to build reservoirs, aqueducts, levees, firebreaks, and flood-control systems because this has always been an extraordinarily variable and sometimes violent environment.

The lesson of California history is not that nature was once benign and humans somehow broke it. The lesson is that California has never been climatically benign.

The New York Times could have used California’s Fifth Climate Change Assessment to discuss sensible adaptation to a state naturally prone to flood, drought, fire, erosion, and enormous weather variability. Instead, it largely presents model projections as an approaching climate reckoning while giving readers almost none of the historical context needed to judge those projections.

California doesn’t need another climate horror story. It needs reporters willing to look backward at the data before confidently telling readers what catastrophe awaits them ahead.

Estonian Scientists Uncover Dangerous Resonant Currents Threatening Ships in Varna Canal

Estonian scientists from Tallinn University of Technology (TalTech) have identified dangerous resonant water oscillations in the canal linking Lake Varna (Bulgaria) to the Black Sea.⁠

Power Spectral Density (PSD) is a fundamental tool in signal processing and time-series analysis. It describes how the power (or variance) of a signal is distributed across different frequencies.

A large container ship navigating through Varna Canal, with turbulent waters and a backdrop of industrial cranes and buildings under a cloudy sky. The image includes wave frequency data and measurements.
AI generated by Grok

Estonian scientists from Tallinn University of Technology (TalTech) have identified dangerous resonant water oscillations in the canal linking Lake Varna (Bulgaria) to the Black Sea.⁠

The findings come from a peer- reviewed study published in Ocean Science (17 August 2026) by Jüri Elken, Laura Piho, and Maarja Kruusmaa, with a related news release from the Estonian Research Council dated 21 October 2026.

Key details

Pilots had long noticed unusually strong currents in the ~2.4 km- long, 300 m-wide navigation canal (part of the Port of Varna complex, Bulgaria’s largest seaport). Researchers deployed three novel Hydromast stations (developed at TalTech’s Centre for Biorobotics) that recorded current speed, direction and water level at 1- minute intervals.

Analysis showed that moderate flows are occasionally interrupted by high-amplitude oscillations lasting tens of minutes. Dominant periods of 37 minutes (first mode of the channel- lake system) and 19 minutes (related to the channel’s quarter- wave mode and the system’s second mode) stood out. These arise from resonance in the sea- channel- lake system, which can amplify movements under certain atmospheric conditions.

Two strong events were recorded:

  • One linked to a meteotsunami (abrupt onset under relatively moderate weather when a weather front moves at resonant speed over shallow coastal waters).
  • Another more than 5 hours after a storm with landward/offshore winds up to 20 m/s.⁠

In the strongest cases, current velocity changed by up to 0.8 m/s and water level by up to 0.8 m within about 10 minutes. Such rapid changes pose hazards to ship navigation, harbor operations, and coastal management.

The work used high- resolution observations plus 1D barotropic analytical and numerical modeling of long waves in the system. It discusses approaches for better detecting and forecasting these sub- hourly oscillations, which standard hourly data often miss. The results have broader relevance for other canal–bay– lake systems and for improving port safety and environmental assessments.

Sources: Estonian Research Council / EurekAlert news release; full paper in Ocean Science (doi:10.5194/os-22-2471-2026).

Map showing the geographical locations of Varna, Constanta, and Istanbul, with highlighted stations around Lake Varna and Varna Bay, including reference points for different stations and channels.
Location of the study areas. Credit: Ocean Science (2026). DOI: 10.5194/os-22-2471-2026

Power Spectral Density (PSD) is a fundamental tool in signal processing and time-series analysis. It describes how the power (or variance) of a signal is distributed across different frequencies.

Simple explanation

Imagine a time series of measurements (e.g., water level or current speed recorded every minute).
PSD answers the question:
“At which frequencies (or periods) is most of the energy and variance concentrated?”

  • High peaks in the PSD → strong, regular oscillations at those frequencies.
  • A flat or slowly declining spectrum → more random or broadband variability.

Mathematical idea

For a continuous signal x(t)x(t), the PSD Sxx(f)Sxx​(f) is essentially the Fourier transform of the autocorrelation function of the signal (Wiener- Khinchin theorem).

In practice, with discrete data it is usually estimated using methods such as:

  • Periodogram
  • Welch’s method (averaging modified periodograms of overlapping segments- the method used in the Varna paper)
  • Multitaper methods

Units are typically power per unit frequency (e.g., m²/Hz for water level, or (m/s)²/Hz for current velocity).

In the Varna- Black Sea paper

The authors computed the PSD of water- level time series at the four stations in the channel. Key results included:

  • Clear spectral peaks at periods of ~37 minutes and ~19 minutes (among others).
  • These peaks were identified as resonant modes of the channel- lake system.
  • Spectrograms (time- varying PSDs) showed that these oscillations became strongly amplified during the two high- current- speed events.

They also used coherence analysis between stations together with the PSD to confirm that the oscillations were nearly synchronous along the channel.

Why PSD is useful here

Sub-hourly resonant oscillations would be almost invisible in hourly data. High- resolution (1- min) measurements and PSD analysis made it possible to:

  1. Detect the natural frequencies of the system.
  2. Link those frequencies to physical modes (first mode of the channel- lake system ≈ 37 min, quarter- wave mode ≈ 19 min).
  3. Quantify when and how strongly the system resonated under atmospheric forcing (including a meteotsunami).
Graph showing air temperature (red line) and air pressure (blue line) over time.
Time series of meteorological and oceanographic data
OS – High current speed events in a harbor channel driven by resonant sub-hourly sea level dynamics: an example from Varna, Black Sea

Welch’s method is one of the most widely used practical techniques for estimating the Power Spectral Density (PSD) of a signal.

It was introduced by Peter D. Welch in 1967 and remains the standard approach in many scientific fields (including oceanography, as used in the Varna paper).

Why do we need it?

A simple periodogram (the squared magnitude of the FFT of the entire record) is a very noisy and statistically inconsistent estimator of the true PSD. Welch’s method reduces this variance by averaging.

How Welch’s method works (step by step)

  1. Divide the time series into overlapping segments
    • The full record of length NN is split into shorter segments of length LL.
    • Adjacent segments usually overlap by 50 % (or sometimes 75 %).
    • Example: a 3- month record of 1- minute data can be divided into many overlapping 1- day or 6- day segments.
  2. Apply a window function to each segment
    • A tapering window (Hanning, Hamming, Blackman, etc.) is multiplied with each segment.
    • This reduces spectral leakage caused by the abrupt edges of the finite- length segments.
  3. Compute the modified periodogram of each windowed segment
    • Take the FFT of the windowed segment and square its magnitude.
    • Normalize appropriately so the result has the correct physical units (power per frequency).
  4. Average all the modified periodograms
    • The final PSD estimate is simply the average of all the individual periodograms.
    • Averaging dramatically reduces the variance of the estimate.

Mathematical summary

If xi(n)xi​(n) is the ii-th windowed segment and UU is a normalization factor that accounts for the window’s energy, the Welch PSD estimate is:S^(f)=1KU∑i=1K∣∑n=0L−1xi(n)e−j2πfn∣2where KK is the number of segments.

Trade-offs (important practical points)

ParameterEffect of increasing itTypical choice
Segment length LLBetter frequency resolutionLong enough to resolve the periods of interest
Number of segments KKLower variance (smoother spectrum)As many as possible
OverlapMore segments → lower variance50 % (most common)
Window typeControls leakage vs. main- lobe widthHanning is the default choice

In the Varna paper

The authors used Welch’s method with:

  • Longer segments (e.g., 6 days) to examine the broader spectrum (periods from minutes to ~15 hours).
  • Shorter segments (e.g., 1 day) to better resolve the higher- frequency sub-hourly peaks (the important 37 min and 19 min oscillations).

Advantages of Welch’s method

  • Greatly reduced variance compared with a single periodogram.
  • Relatively simple and computationally efficient.
  • Works well with real- world (non- stationary, noisy) data.
  • Easy to implement in MATLAB (pwelch), Python (scipy.signal.welch), R, etc.

Limitations

  • Frequency resolution is limited by the chosen segment length.
  • Over- smoothing can hide closely spaced peaks if segments are too short or too many averages are taken.
  • Assumes the process is roughly stationary within each segment.
Line graph showing elevation changes in meters over time from March 13 to April 1.
Water level variability at Stn. 1 from 9 March to 5 April 2025 with a 12 h window and 6 h overlap over successive segments.
OS – High current speed events in a harbor channel driven by resonant sub-hourly sea level dynamics: an example from Varna, Black Sea

High current speed events in a harbor channel driven by resonant sub- hourly sea level dynamics: an example from Varna, Black Sea

Abstract

Current and sea-level observations in the 2.4 km-long, 300 m-wide channel between Varna Lake and the Black Sea, conducted by three novel Hydromast stations with a 1 min resolution, revealed that moderate sub-hourly dynamics were occasionally interrupted by high-amplitude oscillations with a period of a few tens of minutes. The resonant excitation of the events was studied using barotropic 1D analytical and numerical methods. Basic features of high-intensity sub-hourly variations can be interpreted as linear barotropic long waves in a sea-channel-lake system with resonant and damped forcing. The observed 37 min oscillations, identified from the power spectra, spectrogram, and wavelet analysis, can be explained as the first mode of the channel-lake system. Another period of 19 min resembles the zero, quarter-wave mode of the channel and the second mode of the channel-lake system. During the measurement period, two high-amplitude events were highlighted. One of the events is interpreted as having been caused by a meteotsunami; moderate meteorological conditions prevailed; strong channel oscillations began abruptly and lasted for a few cycles. The second event occurred more than 5 h after landward winds up to 20 m s⁻¹. The observed maximum changes in current and sea level – up to 0.8 m s⁻¹ and 0.8 m, respectively, over 10 min – are harmful to ship navigation, harbor operations, and coastal management. Building on these observations, approaches for detecting and forecasting strong sub-hourly oscillations are discussed.

Key points from the paper

  • Study area: Navigation Channel 3 (the older, northern canal) connecting Lake Varna to Varna Bay and the Black Sea, part of Bulgaria’s largest port complex.
  • Measurements: Three Hydromast stations recorded current velocity, direction, and water level at 1- minute resolution (mainly February- May 2025).
  • Main findings:
    • Background sub- hourly variability is moderate.
    • Resonant oscillations (especially ~37 min and ~19 min periods) can be strongly amplified.
    • Rapid changes of ~0.8 m/s in current and ~0.8 m in water level within ~10 minutes pose real risks to shipping and port operations.
  • The authors interpret the events using 1D shallow-water (barotropic long-wave) theory and discuss detection and forecasting methods useful for pilots and harbor authorities.

Downloads available on the page:

  • Full PDF article (≈8.7 MB)
  • Full- text XML
  • BibTeX and EndNote citation files

How to cite:
Elken, J., Piho, L., and Kruusmaa, M.: High current speed events in a harbor channel driven by resonant sub-hourly sea level dynamics: an example from Varna, Black Sea, Ocean Sci., 22, 2471–2490, https://doi.org/10.5194/os-22-2471-2026, 2026.

This is the official open- access page for the peer- reviewed paper that underpins the recent news about dangerous water oscillations between Lake Varna and the Black Sea.

Journal: Ocean Science, Volume 22, pages 2471–2490, 2026

DOI: 10.5194/os-22-2471-2026,

https://doi.org/10.5194/os-22-2471-2026

Published: 17 August 2026

Provided: Estonian Research Council

Authors: Jüri Elken,
Laura Piho,
and Maarja Kruusmaa