Archive for the ‘sea levels’ Category


No acceleration in the historical trend. No correlation with CO2 increase. End of story.
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We have been studying climate change and potentially associated sea level changes resulting from melting ice and warming oceans for a half century, says CFACT.

In the 1970s our primary concern was global cooling and an advancing new ice age.

Many believe that increasing quantities of carbon dioxide in our atmosphere could result in rising levels of the sea in general. The record does not show this to be true.

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Credit: alaskapublic.org


A researcher said: “Remarkably, the data suggest that the ice sheets can change in response to more than just global climate,” calling into question some long-held ideas. A professor connected to the study commented: “These findings appear to poke a hole in our current understanding of how past ice sheets interacted with the rest of the climate system, including the greenhouse effect.” Well, fancy that. The commentary notes that ‘global temperatures were relatively stable at the time of the fall in sea level, raising questions about the correlation between temperature, sea level and ice volume’. In short, the ice sheets grew faster than scientists had thought.
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Princeton scientists found that the Bering Land Bridge, the strip of land that once connected Asia to Alaska, emerged far later during the last ice age than previously thought, says Eurekalert. 

The unexpected findings shorten the window of time that humans could have first migrated from Asia to the Americas across the Bering Land Bridge. 

The findings also indicate that there may be a less direct relationship between climate and global ice volume than scientists had thought, casting into doubt some explanations for the chain of events that causes ice age cycles.

The study was published on December 27 in the Proceedings of the National Academy of Sciences.

“This result came totally out of left field,” said Jesse Farmer, postdoctoral researcher at Princeton University and co-lead author on the study. “As it turns out, our research into sediments from the bottom of the Arctic Ocean told us not only about past climate change but also one of the great migrations in human history.”

Insight into ice age cycles

During the periodic ice ages over Earth’s history, global sea levels drop as more and more of Earth’s water becomes locked up in massive ice sheets.

At the end of each ice age, as temperatures increase, ice sheets melt and sea levels rise. These ice age cycles repeat throughout the last 3 million years of Earth’s history, but their causes have been hard to pin down.

By reconstructing the history of the Arctic Ocean over the last 50,000 years, the researchers revealed that the growth of the ice sheets — and the resulting drop in sea level — occurred surprisingly quickly and much later in the last glacial cycle than previous studies had suggested.

“One implication is that ice sheets can change more rapidly than previously thought,” Farmer said.

During the last ice age’s peak of the last ice age, known as the Last Glacial Maximum, the low sea levels exposed a vast land area that extended between Siberia and Alaska known as Beringia, which included the Bering Land Bridge. In its place today is a passage of water known as the Bering Strait, which connects the Pacific and Arctic Oceans.

Based on records of estimated global temperature and sea level, scientists thought the Bering Land Bridge emerged around 70,000 years ago, long before the Last Glacial Maximum.

But the new data show that sea levels became low enough for the land bridge to appear only 35,700 years ago. This finding was particularly surprising because global temperatures were relatively stable at the time of the fall in sea level, raising questions about the correlation between temperature, sea level and ice volume.

“Remarkably, the data suggest that the ice sheets can change in response to more than just global climate,” Farmer said. For example, the change in ice volume may have been the direct result of changes in the intensity of sunlight that struck the ice surface over the summer.

“These findings appear to poke a hole in our current understanding of how past ice sheets interacted with the rest of the climate system, including the greenhouse effect,” said Daniel Sigman, Dusenbury Professor of Geological and Geophysical Sciences at Princeton University and Farmer’s postdoctoral advisor.

“Our next goal is to extend this record further back in time to see if the same tendencies apply to other major ice sheet changes. The scientific community will be hungry for confirmation.”

Full article here.
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Study: The Bering Strait was flooded 10,000 years before the Last Glacial Maximum


Are the models wrongly expecting sea level rise to closely mirror the rate of increase in atmospheric CO2 content, in all regions? It seems it doesn’t work like that. The study itself says: ‘As for simulation of the interannual variance, good agreement can be seen across different models, yet the models present a relatively low agreement with observations. The simulations show much weaker variance than observed’.
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According to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change, the global mean sea level has risen faster since 1900 than over any preceding century in the last 3000 years, says Eurekalert.

This makes hundreds of coastal cities and millions of people vulnerable to a threat of higher water levels.

State-of-the-art climate models provide a crucial means to study how much and how soon sea levels will rise.

However, to what extent these models are able to represent sea level variations remains an open issue.

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Credit: OH 237 @ Wikipedia


Vastly higher? Enormous? Staggering? – should we be shocked? No, because none of these words from the article below appear in the study itself, which notes: ‘We find that, between 1960 and 1989, sea level in the Mediterranean fell’. It then ‘started accelerating rapidly’. The study also admits: ‘The relative contributions from sterodynamic changes (i.e., changes in ocean density and circulation) and land-ice melting to this recent increase in the rate of Mediterranean sea-level rise remain unclear.’ Looks like the press release resorted to colourful language.
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Scientists from the National Oceanography Centre (NOC) have discovered a substantial rise in sea-levels in the Mediterranean Sea, using a vital new method to measure changes in sea-level, says the NOC.

The study, published in Journal of Geophysical Research: Oceans, demonstrated that sea levels in the Mediterranean Sea have risen at vastly higher rates over the past 20 years compared to the entirety of the 20th century.

The study revealed that sea level in the Mediterranean Sea increased by about 7cm in the period 2000–2018.

Previous changes in sea-level rise in the Mediterranean Sea have been highly unpredictable due to limited observational data but using this latest method, scientists analysed sea-level data from tide gauges and satellites to reveal an enormous increase as a result of ocean warming and land ice-melt.

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Antarctica’s George VI Ice Shelf [image credit: CIRES Colorado Univ.]


Assumptions challenged by new data. Talk of “potentially important implications for global sea-level rise estimates”.
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Some estimates of Antarctica’s total contribution to sea-level rise may be over- or underestimated, after researchers detected a previously unknown source of ice loss variability, says Phys.org.

The researchers, from the University of Cambridge and Austrian engineering company ENVEO, identified distinct, seasonal movements in the flow of land-based ice draining into George VI Ice Shelf—a floating platform of ice roughly the size of Wales—on the Antarctic Peninsula.

Using imagery from the Copernicus/European Space Agency Sentinel-1 satellites, the researchers found that the glaciers feeding the ice shelf speed up by approximately 15% during the Antarctic summer.

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Antarctica


Climate cycles and natural variability do exist then?! No need to re-visit those discussions. Quote: “One of the key findings is that the ice sheet was responding to temperature changes in the Southern Ocean”. The study says: ‘Our findings imply that oscillating Southern Ocean temperatures drive a dynamic response in the Antarctic ice sheet on millennial timescales, regardless of the background climate state.’
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By analyzing unusual rock samples collected years ago in Antarctica, scientists at the University of California, Santa Cruz, have discovered a remarkable record of how the East Antarctic Ice Sheet has responded to changes in climate over a period of 100,000 years during the Late Pleistocene, says Phys.org.

The East Antarctic Ice Sheet is the world’s largest ice mass. Understanding its sensitivity to climate change is crucial for efforts to project how much sea level will rise as global temperatures increase.

Recent studies suggest it may be more vulnerable to ice loss than previously thought.

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2015 Gulf of Carpentaria mangrove die-off, from space [image credit: NASA]


Even the type of local tides was involved. Researchers conclude: we can chalk the 2015 mass death up to “natural causes.”
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Over the summer of 2015, 40 million mangroves died of thirst, says Phys.org.

This vast die-off—the world’s largest ever recorded—killed off rich mangrove forests along fully 1,000 kilometers of coastline on Australia’s Gulf of Carpentaria.

The question is, why? Last month, scientists found a culprit: a strong El Niño event, which led to a temporary fall in sea level.

That left mangroves, which rely on tides covering their roots, high and dry during an unusually dry early monsoon season.

Case closed. Or is it?

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Some like to call it the Doomsday Glacier. The research results are probably open to a variety of interpretations, in terms of predictions. But we’re told that whatever is being observed at present is by no means exceptional, making attempts at attribution of its ever-changing condition to human activity even more problematic. Volcanic activity is an obvious confounding factor here.
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The Thwaites Glacier in West Antarctica — about the size of Florida — has been an elephant in the room for scientists trying to make global sea level rise predictions, says Science Daily.

This massive ice stream is already in a phase of fast retreat (a “collapse” when viewed on geological timescales) leading to widespread concern about exactly how much, or how fast, it may give up its ice to the ocean.

The potential impact of Thwaites’ retreat is spine-chilling: a total loss of the glacier and surrounding icy basins could raise sea level from three to 10 feet.

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Credit: British Antarctic Survey


Much ado about sea ice in recent times, but usually in terms of promoting climate alarm. On closer inspection East Antarctica (2/3rds of the continent) tells a somewhat different story.
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Some ice shelves in the eastern Antarctic have grown in the last 20 years despite global warming, a study suggests.

Researchers say that sea ice, pushed against the ice shelves by a change in regional wind patterns, may have helped to protect the ice shelves from losses, reports Yahoo News.

Ice shelves are floating sections of ice attached to land-based ice sheets and they help guard against the uncontrolled release of inland ice into the ocean.

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This won’t exactly be music to the ears of the climate alarmist tendency, which prefers to claim that people somehow dictate the course of climate variations.
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The Sun’s energy affects our climate but its influence is often ignored as changes in its intensity are very small. Its effect might be subtle but over decadal periods it adds up to being significant as a series of recent papers show, says Net Zero Watch.

Scientists from the University of California, Irvine, the National Taiwan Normal University, and the Institute of Atmospheric Physics, of the Chinese Academy of Sciences, Beijing, find that the 11-year solar cycle has a significant correlation with sea surface temperature variations in the North-eastern Pacific.

They believe that the Sun’s influence is first seen and then amplified in the lower stratosphere, but it then alters the circulation in the troposphere which then affects the temperature of the ocean.

They note that the changes have a structure similar to that of the Pacific meridional mode – an interaction between trade winds and ocean evaporation which is an important trigger of the central Pacific (CP) type of the El Niño-Southern Oscillation (ENSO).

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Miami, Florida [image credit: phys.org]


A practical approach to weather-related local problems, without any overblown climate alarm propaganda.
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FORT LAUDERDALE, Fla. — Gov. Ron DeSantis announced a series of steps to defend Florida against rising sea levels Tuesday, even as he denounced the use of the term “global warming” as a “pretext to do a bunch of left-wing things”, says Climate Depot.

The governor submitted 76 projects to the state Legislature to improve drainage, raise sea walls and take other steps to fight flooding across the state.

The state would spend about $270 million, with local matches typically required.

“We’re a low-lying state, we’re a storm-prone state, and we’re a flood-prone state,” DeSantis said at a news conference in Oldsmar, just outside Tampa.

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Doomed by predictions it seems. Although sea levels have been very slowly rising at a more or less known rate in many places around the world since about the mid-19th Century, predictions of an accelerating rate in the next decades are based on climate models, guesses at government climate policies and attribution of vast powers to trace gases. ‘Scientists say…’
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Like many others who came to Fairbourne, Stuart Eves decided the coastal village in northern Wales would be home for life when he moved here 26 years ago, says USA Today (from AP).

He fell in love with the peaceful, slow pace of small village life in this community of about 700 residents nestled between the rugged mountains and the Irish Sea.

“I wanted somewhere my children can have the same upbringing as I had, so they can run free,” said Eves, 72, who built a caravan park in the village that he still runs with his son. “You’ve got the sea, you’ve got the mountains. It’s just a stunning place to live.”

That changed suddenly in 2014, when authorities identified Fairbourne as the first coastal community in the U.K. to be at high risk of flooding due to climate change.

Predicting faster sea level rises and more frequent and extreme storms due to global warming, the government said it could only afford to keep defending the village for another 40 years.

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An obvious problem with the new Environment Agency report reportis its use of climate scenario RCP8.5, which has been widely discredited as unrealistic, impossible and so on. Surely that ought to render any related comments unsuitable as advice to a government. EA report extracts follow.
Air temperature and precipitation: We used RCP4.5 and RCP8.5 to represent climate scenarios that meet or exceed global warming +2°C and +4°C above pre-industrial by 2100.
Sea level rise: For our FCERM schemes we assess a range from the 70th to the 95th percentile of UKCP18 RCP8.5.
River flows: They are relative to a 1981-200 baseline and based on the 50th percentile of UKCP18 RCP8.5, which is consistent with at least a +4°C warming scenario by the end of the century.
Future weather: The projected values for future hot weather and wet weather are taken from UKCP Local (2.2 km) (Met Office, 2019), which complements the UKCP18 projections with data at a higher spatial and temporal resolution than previous climate projections, giving us greater detail on the 52 of 90 frequency and intensity of extreme weather. These projections are only available for a RCP8.5

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The Environment Agency has issued a stark warning on climate change: “Adapt or die”, says ITV News.

In a new report the Government body has preparations need to be made for the inevitable effects of climate change such as more flooding, an increased number of droughts and rising sea levels.

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alarmism1

Credit: nationalreview.com

Anything supposedly ‘rapidly increasing’ or ‘extreme’ in Earth’s climate now or in the near future has to be treated with some suspicion, to say the least. Experience tells us alarmists armed with assumptions don’t need much excuse to go off the deep end to try and stir up the populace.
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In the mid-2030s, every U.S. coast will experience rapidly increasing high-tide floods, when a lunar cycle will amplify rising sea levels caused by climate change, predicts Phys.org.

High-tide floods—also called nuisance floods or sunny day floods—are already a familiar problem in many cities on the U.S. Atlantic and Gulf coasts. The National Oceanic and Atmospheric Administration (NOAA) reported a total of more than 600 such floods in 2019.

Starting in the mid-2030s, however, the alignment of rising sea levels with a lunar cycle will cause coastal cities all around the U.S. to begin a decade of dramatic increases in flood numbers, according to the first study that takes into account all known oceanic and astronomical causes for floods.

Led by the members of the NASA Sea Level Change Science Team from the University of Hawaii, the new study shows that high tides will exceed known flooding thresholds around the country more often.

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emp_penguin

Emperor penguins, Antarctica [image credit: USAF / Wikipedia]

Too much alarm coming from climate models, again. This new research finds ‘some regions near Antarctica even cool under climate change’.
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The melting rate of the Antarctic ice sheet is mainly controlled by the increase of ocean temperatures surrounding Antarctica.

Using a new, higher-resolution climate model simulation, scientists from Utrecht University found a much slower ocean temperature increase compared to current simulations with a coarser resolution, reports Phys.org.

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Credit: University of Liverpool / National Oceanography Centre (Liverpool branch)


The graph looks consistent with mild warming following the Little Ice Age. About 30 cms. or 1 foot of sea level rise in 130 years since 1890 is nothing remarkable. The average duration of solar cycles was longer in the 19th century than in the 20th but that trend is reversing now, with a lot more sunspot-free days per cycle. Climatic effects may follow.
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A study published by University of Liverpool scientists, alongside colleagues from the Liverpool branch of the National Oceanography Centre, has uncovered and analyzed new sea level records from the nineteenth century which show that the increased rate of the rise of British sea level took place from 1890 onwards, says Phys.org.

Nowadays, sea level measurements around the British Isles are made by tide gauges which record digitally and transmit the data automatically.

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In the Maldives


Just as the late Nils-Axel Mörner, a lifelong sea levels researcher, explained in an interview about two years ago. Let’s hope the climate miserablists now give up on their ‘drowning islands’ nonsense.
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New research says hundreds of islands in the Pacific are growing in land size, even as climate change-related sea level rises threaten the region, says ABC News Australia.

Scientists at the University of Auckland found atolls in the Pacific nations of Marshall Islands and Kiribati, as well as the Maldives archipelago in the Indian Ocean, have grown up to 8 per cent in size over the past six decades despite sea level rise.

They say their research could help climate-vulnerable nations adapt to global warming in the future.

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Hypothetical map of Doggerland [image credit: ancient-origins.net]


This seems semi-topical on the day Britain signs off on its new deal with the EU countries. Going back into history, but not all that far back, the river Thames flowed into the Rhine. North Sea trawlers still find bones of mammoths and other such fossils in their nets today.
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For a long time, scientists believed that a powerful tsunami destroyed Doggerland 8,200 years ago, says DW.com.

Sediment analysis now suggests that the land once connecting Great Britain with the rest of Europe had a later demise.

Around 10,000 years ago, at the end of the last ice age, the sea level in northern Europe was still about 60 meters (197 feet) below what it is today.

The British Isles and the European mainland formed a continuous landmass.

Relatively large rivers crossed this landmass, but in a different way than we know today.

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Topographic map of Greenland


We’re told ‘The North Atlantic region is awash with geothermal activity’. Any day now we should be hearing how a few extra molecules of (human-caused) CO2 make the Earth’s innards hotter than they used to be. Or maybe we won’t.
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A team of researchers understands more about the melting of the Greenland ice sheet, says SciTech Daily.

They discovered a flow of hot rocks, known as a mantle plume, rising from the core-mantle boundary beneath central Greenland that melts the ice from below.

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Antarctica


If they were hoping to see a steady rate of change that matched carbon dioxide emission levels, they were disappointed. Natural variations inconveniently got in the way, two in particular: ‘When two extreme snowfall events in 2009 and 2011 dropped around 600 gigatons of snow and ice, the East Antarctic Ice Sheet thickened so much that it temporarily halted the entire continent’s ice losses, said Wang—a pattern that had previously escaped notice.’
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A new analysis of long-term satellite records shows the East Antarctic Ice Sheet is unexpectedly dependent on fluctuations in weather.

This study may improve models of how much sea levels will rise, says Eos News.

As more coastal communities face the looming threat [Talkshop note: unsupported assertion] of rising sea levels, it’s more important than ever to accurately predict changes in one of the greatest potential sources of sea level rise—the melting of Antarctica’s massive ice sheet.

Recently, scientists analyzed nearly 2 decades’ worth of data from sensitive NASA satellites documenting mass changes in the Antarctic Ice Sheet.

They found the ice inventory ebbed and flowed across the continent in unexpectedly variable patterns.

Traditionally, some groups of Antarctic researchers have assumed the rate of change across the ice sheet is constant, but they drew their conclusions from data sets that spanned only a few years, said Lei Wang, a geodesist at The Ohio State University who will present this research at AGU’s virtual Fall Meeting 2020.

“These long data records give us the capability to characterize the ice sheet’s variation over a range of timescales,” rather than just modeling seasonal variations and short-term trends, Wang said.

Understanding Long-Term Trends

The Antarctic Ice Sheet, the largest mass of ice on Earth, is divided into two unequal portions, with the East Antarctic Ice Sheet covering about two thirds of the continent. The West Antarctic Ice Sheet, although smaller, has historically been more closely studied because it’s melting faster. (The East Antarctic Ice Sheet sits on bedrock above sea level, said Wang, so it is less susceptible to the effects of the warming ocean.) NASA estimates Antarctica has lost 149 billion metric tons of ice per year since 2002.

When so much ice is involved, projections of how sea levels will respond are uncertain—especially when trends already are so difficult to gauge.

Indeed, the field still argues about sea level changes in the past century, said Jim Davis, the study coauthor and a geodesist at the Lamont-Doherty Earth Observatory at Columbia University. “We’ve got to get to the point where we can talk about what’s happening this year in sea level change,” he said.

To do that, researchers need a more sophisticated model of how Antarctica’s shield of ice is evolving.

Full article here.