Archives par mot-clé : Sea level

better to know...?, climate and geology

Rising Seas? No, 3 Dozen S. Florida High-Rises Sinking From Land Subsidence

by Geology, New Science, Dec 18, 2024 in ClimatChangeDispatch

miami beach high rises

Top photo by Ryan Parker on Unsplash

Almost three dozen high-rise condos and luxury hotels along the beach in South Florida are sinking or settling in unexpected ways, in some cases because of nearby construction, according to a new study. [emphasis, links added]

The 35 buildings surveyed along an almost 12-mile (19-kilometer) stretch from Miami Beach to Sunny Isles Beach have sunk or settled by 0.8 to 3.1 inches (2 to 8 cm).

About half of the buildings are less than a decade old, according to scientists at the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science.

The study was published on Friday.

“The discovery of the extent of subsidence hotspots along the South Florida coastline was unexpected,” Farzaneh Aziz Zanjani, the lead author, said in a statement. “The study underscores the need for ongoing monitoring and a deeper understanding of the long-term implications for these structures.”

It’s not uncommon for buildings to sink a little during and soon after construction, but the scientists called their discovery surprising because some of the changes took place several years later.

Limestone under the South Florida beach is interspersed with layers of sand, which can shift under the weight of high-rises and as a result of vibrations from foundation construction.Tidal flows also play a role.

The study used satellite images to capture the changes, with settling most noticeable in buildings in Sunny Isles Beach.

The scientists said preliminary data also suggests sinking or settling further north, along the beaches of Broward and Palm Beach counties.

The stretch of South Florida communities surveyed included Surfside, where the Champlain Towers South building collapsed in June 2021, killing 98 people.

However, that collapse is thought to have been caused by reinforced concrete that deteriorated due to poor maintenance and flawed design.

better to know...?, climate-debate

3 New Studies Confirm Sea Levels Were 5 to 9 Meters Higher 7,000-5,000 Years Ago Than Today

by K. Richard,  Apr 1, 2024 in ClimateChangeDispatch

Modern relative sea levels are near the lowest in the last 7,000 years.

Two studies, independently published, identified Mid-Holocene sea levels in northern Norway (north of the Arctic Circle) as being 7 to 9 meters higher than today before declining to the present (Balascio et al., 2024, Nielsen et al., 2024). [emphasis, links added]

This region of the Arctic was warm enough to support human settlements and boat harbors during the Medieval Warm Period.

As the climate deteriorated into the Little Ice Age cooling centuries after the Medieval warmth, the accompanying sea level fall led to abandoned residences, ships, and harbors.

The seas had become too shallow to sail in.

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climate-debate

SE Asian Sea Levels Were 3-4 Meters Higher Than Today 7-4 Thousand Years Ago

by K. Richard, Dec 12, 2023 in NoTricksZone

Comprehensive data analysis shows relative sea levels were anywhere from 1 to 7 meters (~3.9 m) higher than present throughout the Mid-Holocene at 15 of 16 assessed sites across Southeast Asia.

A new study (Li et al., 2023) compiles highstand records from sites spanning Thailand, Vietnam, Singapore, Malaysia, Borneo, Sunda Shelf, Makassar Strait…and indicates that throughout southeast Asia there was a “peak RSL [relative sea level] highstand of ~3.9 ±1.1 m at ~6 ka BP or later.”

Of the 16 locations assessed, just 1 did not indicate sea levels were higher than present back when CO2 levels were alleged to be 265 ppm.

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climate-debate

Media Regurgitate Nonsense About Greenland Ice Sheet And Sea Level Rise

by D. Burton, Apr 3, 2023 in ClimateChangeDispatch

CNBC and the Potsdam Institute (PIK) report that:

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

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

KEY POINTS:

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

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

 

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

Here’s the article.

Here’s the paper.

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

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

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

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

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

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

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climate-debate

Bringing order to the chaos of sea level projections

by Royal Netherlands Institute for Sea Research, May 18, 2022 in ScienceDaily

In their effort to provide decisionmakers with insight into the consequences of climate change, climate researchers at NIOZ, Deltares and UU are bringing order to the large amount of sea level projections, translating climate models to expected sea level rise. Their new overview study was published in the scientific journal Earth’s Future. “These results offer tools for decision making on the shorter and longer term.”

Aimée Slangen is a climate scientist at NIOZ and co-author of the IPCC climate report. Together with climate adaptation experts Marjolijn Haasnoot and Gundula Winter from Deltares and Utrecht University, both also IPCC authors, Slangen investigated the similarities and differences between the many sea level projections published in recent years.

Eight families of projections

“We found that the set of more than 80 different projections can be reduced to eight ‘families’,” says Slangen. “Within each of the families of projections that we identified, researchers have often used similar data, but they have for instance used different model approaches. As a result, every new publication resulted in different amounts of projected sea level rise, depending on whether the publication focused on the shorter term or the longer term, or depending on the models used to estimate the processes causing a potentially large contribution of accelerated melting of the Antarctic ice sheet.”

These details are interesting for scientists, but make it more difficult for users to maintain overview. Slangen: “This can be an issue when you have to decide as a government what you are going to do to protect your coasts from rising sea levels. Decision makers can’t adjust their policies with every new publication.”

Half a meter rise before the end of the century

The researchers hope to dispel this doubt, as all families paint a similar picture for the first 50 cm of sea level rise. Slangen: “We will see the first half-meter rise before the end of this century, even if we start reducing greenhouse gas emissions on a large scale. For this period, it therefore makes little difference which family you use for sea level projections.”

According to adaptation expert Haasnoot, this therefore means that we can already start adapting to the consequences of sea level rise now. “Those who have to make the climate-proof decisions can already get started. However, it is important to take into account the uncertainty of the future. If you plan cleverly, you make sure that what you are doing now for a half meter sea level rise can be adjusted later for one meter. That will save a lot of money and effort.”

Models and emission scenarios

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climate and geology, climate-debate

Sea Level: Rise and Fall – Slowing Down to Speed U

by Kip Hansen, Mai 3,2022 in WUWT

Yes, I do know that acceleration, technically, means just a change in velocity.  But, in every day English, we use acceleration to mean an increase in velocity – speeding up — and deceleration as a decrease in velocity – slowing down.  I mention acceleration and deceleration because one of the major talking points of IPCC reported findings about sea level rise, the incessant media mantra, is that “Sea Level Rise is Accelerating”.  (here, here, here, here, here and hundreds more here)

Is sea level rising?  Yes, of course it is.  It has been rising since about 1750-1775, coinciding with the end of the Little Ice Age.  This is widely accepted as shown below:

 

How do we know?  The important aspect of sea level is how it affects the land at the edges of the oceans.  The water level there is measure by tide gauges at the ports and harbors of the world.  The levels recorded by tide gauges are of local Relative Sea Level (RSL) – the level at which the sea surface hits the land.  This measurement includes both the actual rise in the sea surface height (think: distance from the center of the Earth) plus any vertical movement (VLM) of the tide gauge itself, either up or down.  In many locations the land mass itself is subsiding (sinking) due to glacial isostatic adjustment (GIA) as the land mass readjusts itself for the melting of the glaciers of the last great  Ice Age and at most tide gauge locations, the structure to which the tide gauge tself is attached, such as a pier or dock or sea wall, is also itself subsiding due to compaction of the soil underneath and the fact that many such locations are built on man-made filled substrate.  To see if sea level is rising, it is only necessary to look at high quality tide gauge records for whom the VLM is known to be relatively constant.  The linearity of these graphs is typical, there are many, many more.

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climate-debate

34 Years of Flawed, Failed & Grossly Misrepresented Global Sea Level Rise Speculation

by L. Hamlin, Mar 30, 2022 in WUWT

For decades climate alarmists in the UK, EU and U.S. have been making flawed and failed exaggerated claims regarding accelerating global level sea level rise being caused by increasing man made CO2 emissions as one means of politically bullying the world’s nations into mandating immensely costly, bureaucratically onerous and completely ineffective global CO2 reductions from these nations.

The flawed CO2 reduction schemes in the EU and UK have created significant declines in energy availability and reliability because of these nations excessive reliance on unreliable, nondispatchable, backup power reliant and costly renewable energy. These politically contrived emissions and energy incompetent policies have resulted in greatly increasing energy costs for EU and UK nations that negatively impacted their economies while significantly increasing their dependence on energy from other nations.

This energy dependence includes greatly increased needs for natural gas, petroleum and coal supplies obtained through other nations and especially from Russia which (before sanctions) provided about 40% of the EU’s natural gas energy as well as being the EUs main supplier of crude oil (27%) and hard coal (49%). This data and other information concerning the EU and UK self-inflicted climate alarmist driven energy and economic debacle is addressed here, here and here.

The EUs efforts to build additional liquified natural gas terminals to wean itself off Russian gas is estimated to take at least three years with existing available import shipping facilities already maxed out. Renewables would take even longer. Any new LNG cargoes will have higher costs than the existing Russian pipelines. EU policy makers are stuck with politically damaging options including rationing energy and using more coal which means dumping climate goals. When push comes to shove emission reductions will take second place to economic survival with this huge energy and emissions policy turnaround already underway and being led by Germany.

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better to know...?, climate-debate

AR6 and Sea Level Rise, Part 1

by Andy May, Mar 19, 2022 in WUWT

This is the first of a three-part series on the IPCC’s discussion of sea level rise in their latest report, AR6 (IPCC, 2021). The report claims that the rate of sea level rise is accelerating. It is fair to ask why they think this, what evidence do they offer?

We find the following in the AR6 Summary for Policymakers:

“Global mean sea level increased by 0.20 [0.15 to 0.25] m between 1901 and 2018. The average rate of sea level rise was 1.3 [0.6 to 2.1] mm yr–1 between 1901 and 1971, increasing to 1.9 [0.8 to 2.9] mm yr–1 between 1971 and 2006, and further increasing to 3.7 [3.2 to 4.2] mm yr–1 between 2006 and 2018 (high confidence). Human influence was very likely the main driver of these increases since at least 1971.” [Bold added]

AR6 Summary for Policymakers, page SPM-6 (IPCC, 2021)

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climate and geology, climate-debate

Sinking Sea Level Alarmism: Study By Nevada Scientists Show Surface Motion of Continents “On Average Upward”

by P. Gosselin, Feb 27, 2022 in NoTricksZone

German climate science critical site Die kalte Sonne here reports on a recent study by Hammond et al (2021) titled:  “GPS Imaging of Global Vertical Land Motion for Studies of Sea Level Rise“.

climate-debate

Marshall Islands Growing, Not Shrinking. World Bank’s Embarrassing Error In Alarmist 2021 Report

by C. Rotter, Feb 21, 2022 in WUWT

Last October, just before Glasgow Climate Conference, the World Bank issued a report with a dire warning for the Marshall Islands. It claimed: “Rising sea levels in the atoll nation of Marshall Islands are projected to endanger 40 percent of existing buildings in the capital, Majuro, with 96 percent of the city at risk of frequent flooding induced by climate change.”

The startling claims were based on “new visual models” and that the rising sea levels were due to co2-induced warming.

But now we learn that the model inputs were garbage, and so the model outputs were garbage as well. Nothing of the sort is going to happen to the Marshall Islands anytime soon.

Analysis shows 4% growth from 1945 to 2010!

German climate site Die kalte Sonne here took a closer look at the dramatic claims and found the World Bank report had a grave error: they failed to account for the role that coral reefs play in island building.

A 2015 paper published by Ford et al indeed found that the opposite is happening: the islands are expanding and not sinking and shrinking. The paper’s abstract:

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climate-debate

Why We Must “Quit Worrying About Uncertainty in Sea Level Projections”

by K. Hansen, Dec 2, 2021 in CO2Coalition

It is an interesting read but not because it presents good advice to the scientific community.  Rather, it presents the case that climate and ice models, which are used to make projections, are not up to the task.  While those who program climate models have been trained in what we know about the basic physics involved in the biggest sea level rise issue – ice sheet dynamics – the actual projections by those models depend on parameters that are loose guesses about things we don’t know.  As a result, Bassis says “…recent studies using climate and ice sheet models are, more and more often, coming to very different conclusions about future rates of sea level rise and even about the sensitivity of ice sheets to future warming…”  and because of that, he tells us:

“Large discrepancies among model projections of long-term sea level rise have spawned calls among the scientific community for scientists to work on reducing uncertainty. However, focusing on uncertainty is a trap we must avoid. Instead, we should focus on the adaptation decisions we can already make on the basis of current models and communicating and building confidence in models for longer-term decisions.”

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Kip Hansen is an expert on sea level and sea-level rise. Prolific author of numerous articles on the subjects. WUWT lists 445 commentaries and articles.

He has spent much of his adult life at sea, first as an officer on a merchant ship, and later as a USCG-licensed captain in the Caribbean, where he sailed with his wife while doing humanitarian work (mostly Dominican Republic).

He is a proud member of the CO2 Coalition.

 This commentary was first published by the CO2 Coalition, December 3, 2021

climate-debate

New Data Suggest Greenland’s Relative Sea Levels Were 6 Meters Higher 1,500-2,000 Years Ago

by K. Richard, Oct 28, 2021 in NoTricksZone

The discovery of whale bones and marine shells at ancient beach sites 32 to 36 meters above today’s shorelines have been dated to the Early to Middle Holocene. Beach ridges were still several meters higher than today during Roman and Medieval times.

The relative sea levels of the ancient past can be discerned by identifying the span of years marine shells were deposited on ancient beaches. Also, whales were as likely to wash up on shore thousands of years ago as they do today.

A new study (Souza et al., 2021) uses an alternative dating method to identify when beach ridge systems were still collection sites for sea shells along the west coast of Greenland (Disko Island). The authors find it “particularly interesting” that beach ridges were still elevated ~6 meters above modern sea levels less than 2,000 years ago, as previous studies have suggested the Disko Bay region’s sea levels should have fallen to below present sea level by this time.

The authors also determined the marine shells located 32 meters above present Disko Island shorelines can be dated to about 5,300 years ago. Whale carcasses collected at sites elevated 36 meters above modern have been dated to the Early Holocene.

The highest sea levels of the Holocene, or the Holocene Marine Limit, has been dated to ~9000 years ago. At that time deposits of sea shells on the southwest coast of Disko were as much as “~70 to 80 m above present sea level.”

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climate-debate

Sea Levels Near B.C. Canada Were 90 Meters Higher Than Today 14,500 Years Ago

by K. Richard, Aug 23, 2021 in NoTricksZone

A new study suggests British Columbia (Canada) relative sea levels remained 10 meters higher than they are today until they fell to their present levels in the last ~1800 years. Two other new studies suggest sea levels were still 0.8 to 1 meter higher than today during the Medieval Warm Period.

After the peak of the last glacial about 20,000 years ago, relative sea levels subsequently rose from 120 meters below modern sea levels to heights of 90 meters above today’s by ~14,500 years ago in the Douglas Channel near British Columbia, Canada (Letham et al., 2021).

Sea levels proceeded to fall 75 to 80 meters over the next 3000 years, or about -2.5 meters per century (-25 mm/yr), and then they remained 10-15 m above present for the next ~9000 years.

“We determine that central Douglas Channel was ice-free following the Last Glacial Maximum by ∼14,500 BP and RSL was at least 90 m higher than today. Isostatic rebound caused RSL to fall to 21 m asl by 11,500 BP, though there may have been a glacial re-advance that would have paused RSL fall around the beginning of the Younger Dryas. RSL fell to 10–15 m asl by 10,000 BP, and continued to drop at a slower rate towards its current position, which it reached by ∼1800 years ago.”

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better to know...?, climate-debate

Inside The Acceleration Factory

by W. Eschenbach, Aug 11, 2021 in WUWT

Nerem and Fasullo have a new paper called OBSERVATIONS OF THE RATE AND ACCELERATION OF GLOBAL MEAN SEA LEVEL CHANGE, available here. In it, we find the following statement:

Both tide gauge sea level reconstructions and satellite altimetry show that the current rate of global mean sea level change is about 3 mm yr–1, and both show that this rate is accelerating.

So the claim is that tide gauges show acceleration. Let’s start with a look at the Church and White (hereinafter C&W) estimate of sea level from tide gauges around the world, which is the one used in the Nerem and Fasullo paper. The C&W paper is here.

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better to know...?

Rising Sea Levels No Cause For Apocalyptic Climate Claims

by J. Tennebaum, May 12, 2021 in ClimateChangeDispatch

Former US Energy Department chief scientist Steven Koonin says sea levels rise at changing rates and sees ‘no signs’ of a climate apocalypse.

Here we continue our interview with Dr. Steven Koonin, chief scientist in the US Department of Energy during the Barack Obama administration and author of the just-published book, Unsettled: What Climate Science Tells Us, What It Doesn’t, And Why It Matters

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climate-debate

The Supermoon and SLR

by Kip Hansen, Apr 30, 2021 in WUWT

Dr. Judith Curry sent out a tweet about this article at The Conversation:  “This supermoon has a twist – expect flooding, but a lunar cycle is masking effects of sea level rise“.  The piece is written by Brian McNoldy, a Senior Research Associate, University of Miami and written in conjunction with Covering Climate Now — the climate news propaganda effort headed up by the Columbia Journalism Review and The Guardian.  The Conversation is a member of Covering Climate Now  and a search of their website shows they have published, so far, a total of 86 articles in cooperation with that organization.

McNoldy does a good job explaining what Lunar Nodal Cycle is and how it affects apparent local Relative Sea Level Rise

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Bottom Line:

Miami, Florida has high tide flooding because much of Miami Beach (particularly) is built within a foot or two of normal high tides, and some portions are below normal high tides.  So, of course, Miami will experience tidal flooding again at these predicted higher tides.  For Miami’s real Sea Level story, see my earlier essay:  Miami’s Vice.

climate-debate

Follow the Science: Seas Rising 20 Times Slower than the Media Claim

by J. Taylor, Apr 13, 2021 in ClimateRealism

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According to NASA and NOAA satellite instruments, sea level is rising at a mere 3 millimeters per year, which is a pace of just under one foot per century. (Note, the NASA/NOAA-reported 3.3 mm/year rise in Global Mean Sea Level includes a 0.3 mm “adjustment” that accounts for land rising as glaciers melt. The sea-level rise in relation to coastal shorelines is therefore 3.0 mm/year.) Moreover, the satellite measurements show no significant acceleration during recent decades in the pace of sea-level rise.

Given that seas are rising at a pace of merely one foot per century, which is little if any faster than the pace of sea-level rise throughout the global warming of the 1800s and 1900s, it is almost certain that seas will not rise 20 feet during the next 100 to 200 years. It is also almost certain that seas will not rise two feet during the next 20 years.

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better to know...?, climate-debate

Subsidence In The Bangladesh Basin

by P. Homewood, Mach 26, 2021 in NotaLotofPeopleKnowThat

Absolute sea levels are rising by about 2mm a year, yet the land is subsiding by 2.2cm a year. A small part of this is due to isostasy, but most is evidently the result of “dewatering”, what we would call water extraction. (see here)

Whatever problems farmers in Bangladesh are having, it has nothing to do with climate change.

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climate-debate

We’re Not Gonna Drown! Analyses Show COASTAL SEA LEVEL RISE Is Only 1.69 mm Per Year!

by P. Gosselin, March 23, 2021 in NoTricksZone

UPDATE: Sea level rise near the coasts where people actually live is found to be 1.69 mm/yr. But when crunching the data for the entire ocean, as Willis Eschenbach has shown, a figure of just 1.52 mm/year is computed. 

Hot shot data analyst Zoe Phin at her site examines sea level rise.

There she notes, “Climate alarmists are worried that the sea level is rising too fast and flooding is coming soon. You can find many data images like this on the net:”

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unclassified

Sea Level and the Jersey Shore

by Kip  Hansen, March 22, 2021 in WUWT

Dr. Judith Curry has been writing about Sea Levels and New Jersey [and here], spurred on by a request for an evaluation of the topic from the New Jersey Business & Industry Association(NJBIA).  The NJBIA is concerned because a study by a team of sea level researchers at Rutgers University has called for “draconian policies unsupported by science” that would “harm our economy today” by overreacting to “legitimate concerns about climate change, sea level rise, and flooding”.   Dr. Curry’s full report is titled: “Assessment of projected sea level rise scenarios for the New Jersey Coast”.

Dr. Curry’s CFAN report contains this summary:

The summary conclusions of the CFAN Review are:

—  The sea level projections provided by the Rutgers Report are substantially higher than those provided by the IPCC, which is generally regarded as the authoritative source for policy making. The sea level rise projections provided in the Rutgers Report, if taken at face value, could lead to premature decisions related to coastal adaptation that are unnecessarily expensive and disruptive.

—  Scenarios out to 2050 for sea level rise and hurricane activity should account for scenarios of variability in multi-decadal ocean circulation patterns.

—  Best practices in adapting to sea level rise use a framework suitable for decision making under deep uncertainty. The general approach of Dynamic Adaptive Policy Pathways is recommended for sea level rise adaptation on the New Jersey coast.

I wrote a piece here at WUWT a year ago, titled “Atlantic City:   I’ll meet you tonite…..”, prompted by the Governor of New Jersey’s executive order stating that  “New Jersey has set a goal of producing 100 percent clean energy by 2050.” and  “New Jersey will become the first state to require that builders take into account the impact of climate change, including rising sea levels, in order to win government approval for projects.”  The sea level rise part of this executive order was based on an earlier draft of  the same  study by researchers at Rutgers University.

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better to know...?, climate-debate

False Alarm: IPCC Models Say A Warming Antarctica REDUCES Sea Levels -0.8 Of A Meter By 3000

by K. Richard, March 15, 2021 in NoTricksZone

The IPCC-endorsed anthropogenic global warming (AGW) paradigm finds a warming Antarctica results in more precipitation locked up as ice on the continent. This contributes to reducing sea levels: a -1.2 mm/year−1 mitigation of sea level rise over the next 80 years.

In the 4th IPCC report, Working Group 1 (the physical science) reported that as global temperatures rise, “GCMs [models] indicate increasingly positive SMB for the Antarctic Ice Sheet as a whole because of greater accumulation.” This means that by 2100 Antarctica “would contribute 0.4 to 2.0 mm yr−1 of sea level fall.” Over the next 980 years, Antarctica’s ice accumulation will reduce sea levels by nearly a full meter (-0.8 m by 3000).

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better to know...?

“Acceleration” in Sea-Level Rise Found to Be False – An artifact of Switching Satellites

by P. Homewood, Feb 27, 2021 in NotaLotofPeopleKnwoThat

One of the most common arguments climate alarmists make is that rate of sea-level rise is “accelerating” or rising faster every year.

Sea-level data reported from satellites indicate seas are rising approximately of 3.3 mm/year (See Figure 1). By contrast, tidal stations have recorded a rise of approximately 1 to 2 mm annually, a rate which is little changed over the century or so for which we have adequate records. Indeed, as reported in Climate at a Glance: Sea Level Rise,  the oldest tide gauge in the USA, in New York City, shows no acceleration at all going back to 1850.

Why the large difference?

The answer it turns out is simple. When NASA and NOAA launched new satellites, the data they produced wasn’t the same as the data recorded by earlier satellites.

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Figure 2. NOAA sea level data, showing the trend of each of the full individual satellite records and the overall trend. SOURCE: NOAA Excel Spreadsheet

Full post here.

climate-debate

Munging The Sea Level Data

by W. Eschenbach, Feb 21, 2021 in WUWT

For more than a decade now, I’ve been wondering about a couple of questions.

First, why does the satellite-based sea-level data show that the sea level is rising so much faster than the rise measured at tidal stations on the coastlines around the world? Records from tidal stations show a rise on the order of a couple of mm per year, a rate which is little changed over the century or so for which we have adequate records. But the satellite record (Figure 1) shows a rise of 3.3 mm/year. Why the large difference?

Second, why does the satellite-based sea-level show such significant acceleration? As mentioned above, the sea-level records from tidal stations, which are much longer, show little or no acceleration. But the satellite record claims that the rate of sea-level rise is increasing by about a tenth of an mm per year. That amount of acceleration would double the rate of sea-level rise in about thirty years. Again, why the large difference?

To start with, here’s what the satellite data says, according to the University of Colorado Sea Level Research Group.

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better to know...?, climate-debate

Alarmism Dies In The Maldives: 97% Of 186 Island Coasts Have Grown (59%) Or Not Changed (38%) Since 2005

by C. Rotter, Dec 22, 2020 in WUWT

Reposted from NoTricksZone

By Kenneth Richard on 21. December 2020

Despite sea level rise, a 2019 global analysis (Duvat, 2019) found 89% of 709 island coasts have been either stable or growing in size in recent decades. A new Maldives-only study (Duvat, 2020) finds rapid (>3 to >50%) coastal growth in 110 of 186 Maldives islands from 2005 to 2016. Just 5 islands – 2.7% – actually contracted in size during this period.

Last year Dr. Virginie Duvat published a global assessment of how the Earth’s islands and atolls are faring against the ongoing challenge of sea level rise since satellite monitoring began in the 1980s.

Fortunately she found “no widespread sign of physical destabilization in the face of sea-level rise.” In fact, a) none of the 30 atolls analyzed lost land area, b) 88.6% of the 709 islands studied were either stable or increased in area, c) no island larger than 10 hectare (ha) decreased in size, and d) only 4 of 334 islands (1.2%) larger than 5 ha had decreased in size.

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