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.”
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:
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.
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.
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?
“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]
The study examined the rates and patterns of vertical land motion (VLM) on all locations on Earth’s land surface using GPS imaging. The team estimated the VLM at all tide gauges. The authors were able to make a global assessment of the budget of uplift and subsidence attributable to glacial isostatic adjustment (GIA) and non-GIA sources and provide maps and rates at over 2,300 tide gauges around the world.
The results led the authors to conclude that the surface motion of the continents is on average upward, implying that the unobserved areas (composed of the ocean basins and ice-covered areas) move on average downward with respect to Earth center.
Less than 1% of the stations are on track to reach the IPCC projection
Other scientific studies show zero or even negatively accelerating sea level rise at many locations measured by tide gauges. See here.
For example, the NOAA keeps a coastal station tide list for tracking global linear relative sea level (RSL). The data and charts can be looked at country-by-country here. Overall, only 3 stations show a RSL rise of 7.5 mm/year or more, meaning only three stations (0.08%) are on track to reach the IPCC’s alarmist 75 cm sea level rise projection by 2100.
And if we use the more conservative and realistic 60 cm rise, only 5 stations (1.4%) are on track.
However, after correcting for the GIA the reverse is true, and observed areas subside on average implying that the unobserved areas undergo net non-GIA-related uplift.
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.
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.”
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
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.”
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.”
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.
by P. Homewood, May 6, 2021, in NotaLotofPeopleKnowThat
Over the years, the Guardian has assured us that the Maldives would soon be swamped, unless we mended our ways. Now they are happy to make money out of selling jet setting holidays there to its well heeled readers!
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 Conversationis 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.
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.
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.
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.
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.
— 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.
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).
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.
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
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.
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.
We recall how in 2012, the former President of the Maldives Islands, Mohamed, Nasheed said: “If carbon emissions continue at the rate they are climbing today, my country will be underwater in seven years.”
4 new airports!
Well, today the islands have not gone underwater and remains popular with tourists like never before. And to help with the job of ferrying the 1.7 million (2019) tourists to and from the resort islands, the Maldives have recently opened 4 new airports, according to German site Aero here!
California’s and other American coastal towns are engaged in divisive arguments regards rising sea levels. Although observed sea levels rose less than 8 inches (0.08 inches per year) since 1900, some modelers forecast much bleaker futures. They predict a 2.4-foot rise for every 1°F rise above preindustrial temperatures, then accelerating to nearly 4.5 feet for every 1°F additional increase. Why a dramatic acceleration in sea level? It’s based primarily on dire models, typically presented to coastal planning commissions as ‘best science’, suggesting increasing ice instability and Antarctica ice sheet collapse. “Antarctica has the potential to contribute more than 3.3 feet of sea-level rise by 2100 and more than 49 feet by 2500.”
Those models have prompted some citizens to argue we must abandon the coasts via managed retreat. Others argue we should build better sea walls. But how high? Others rightfully ask, “how trustworthy are those models?” Model predictions of a collapsing Antarctica ice sheet are not based on observations. Models of Antarctica’s catastrophic ice collapse are attempts to explain ancient sea levels such as the 30-foot higher levels 120,000 years ago.
There are good reasons toquestion catastrophic models. For one, away from the coast Antarctica’s surface temperatures average −70 °F. Antarctica’s extremely cold surfacesrequire global warming to increase many, many times more before surface glaciers could ever melt. For another, although greenhouse theory predicts increasing CO2 concentrations will raise temperatures, greenhouse theory also predicts added CO2 has a cooling effect on Antarctica (Wijngaarden & Happer 2020, Schmithüsen 2015).
by J. Taylor, Oct 19, 2020 in ClimateChangeDispatch
A new study posted at ClimateAtAGlance.com documents that most small islands are growing, not losing land to sea-level rise, and island nations are attracting growing populations rather than shedding climate refugees.
The new climate summary drives a stake into the heart of alarmist assertions that climate change and rising seas are threatening island nations and their populations.
Objective measurements show that islands and atolls are growing in size, not disappearing under rising seas.
Rising seas bring sand and sediment, which build up coastal shorelines and are more than keeping pace with rising waters.
Also, coral, as living organisms growing near sea level, build up their height along with the rising sea.
For example, climate activists often claim the island nation of Tuvalu is shrinking due to rising seas and spawning climate refugees.
However, a recent peer-reviewed study found eight out of Tuvalu’s nine coral atolls have grown in size during recent decades, and three-fourths of Tuvalu’s 101 reef islands have similarly grown in size.
Also, Tuvalu’s population is consistently growing, not declining, with 20% more people living on Tuvalu now than 30 years ago. Tuvalu’s population has doubled since 1970.
Additional peer-reviewed studies (see here, here, and here) confirm the same processes are allowing – and will continue to allow – other Pacific islands to keep up with rising seas.
by P. Homewood, September 3, 2020 in NotaLotofPeopleKnowThat
Whether we enter another period of AMO related cooling in coming decades remains to be seen. But what the data conclusively shows is that, as far as the UK is concerned, the recent rate of sea level rise is not unprecedented, nor is there any evidence of it accelerating.
La géologie, une science plus que passionnante … et diverse