Archives par mot-clé : Sea level

Isle de Jean Charles & Sea Level Rise

by P. Homewood, April 20, 2019 in NotaLotOfPeopleKKnowThat


The Isle de Jean Charles, Louisiana. It’s been largely submerged beneath the sea over the last 6 decades. The program gives the definite impression that the main reason for this inundation is sea level rise due to melting ice and thermal expansion of the oceans – driven by man-made climate change. Attenborough does mention oil extraction as a cause but his narrative is lost to the general tone of the messaging that this is a “climate catastrophe” and that the families driven from their homes in this part of Louisiana are some of the world’s first “climate refugees”. This is palpable bullshit.

 

https://tidesandcurrents.noaa.gov/sltrends/sltrends.html

CA sea level rise alarmist study ignores 30 years of NOAA data with no coastal sea level rise acceleration

by Larry Hamlin, March 13, 2019 in WUWT


NOAA tide gauge data measurements exist for 17 locations along the California coast with 8 of these locations having actual measured sea level rise data covering periods for more than 70 to 120 years in duration.

This measured data shows that none of these California locations are experiencing coastal sea level rise acceleration since climate alarmist first made such erroneous and flawed sea level acceleration claims before the U.S. Senate in 1988.

Climate alarmists and their supporting media conveniently conceal the fact that their flawed claims have been hyped for the last 30 years as they continue to try again and again to make the same repeated but flawed claims apparently hoping that the public will forget their long track record of failure and exaggeration.

NOAA measured tide gauge data shows that coastal sea level rise at Ca. locations varies between 3 to 12 inches per century and have remained at those levels during the long measurement periods during which actual measured data have been recorded with a sample of that measured data shown below for San Diego, La Jolla, Los Angeles and San Francisco.

New Paper: Widespread Collapse Of Ice Sheets ~5000 Years Ago Added 3-4 Meters To Rising Seas

by K. Richard, March 11, 2019 in NoTricksZone


During the Mid-Holocene, when CO2 concentrations were stable and low (270 ppm), Antarctica’s massive Ross Ice Shelf naturally collapsed, adding the meltwater equivalent of 3-4 meters to sea levels.

Because CO2 concentrations changed very modestly during the pre-industrial Holocene (approximately ~25 ppm in 10,000 years), climate models that are predicated on the assumption that CO2 concentration changes drive ocean temperatures, ice sheet melt, and sea level rise necessarily simulate a very stable Holocene climate.

In contrast, changes in ocean temperatures, ice sheet melt, and sea level rise rates were far more abrupt and variable during the Holocene than during the last 100 years.

Modern ocean changes are barely detectable in the context of natural variability

Image Source(s): Rosenthal et al., 2013Climate Audit

What’s Natural? Changing Sea Levels – Part 1

by Jim Steele, February 23, 2019 in WUWT


Local sea levels appear to rise when ocean volumes increase, but also when the land sinks. Scientists increasingly warn that coastal cities are sinking much faster than ocean volumes are rising. Pumping out groundwater not only causes lands to sink, it increases the oceans’ volume. China’s Huanghe Delta is sinking 10 inches a year. Southeast Asian cities battle sinking rates of 1.2 to 2.4 inches per year. Regions around Houston, Texas had sunk 10 feet by 1979; a disaster waiting to happen where hurricanes commonly generate 15-foot storm surges. Likewise, New Orleans was doomed by sinking 1.4 inches per year. Built on marshland, San Francisco’s airport sinks 0.4 inches per year.
In contrast, ocean warming plus added glacial meltwater are estimated to have only added 0.06 inches per year to sea level from 1850 to 1990, punctuated by decades that accelerated sea level rise to 0.14 inches a year. Still, that fastest rate of modern sea level rise remains only one-tenth of New Orleans’ sinking rate.

A global assessment of atoll island planform changes over the past decades

by E. Duvat, October 25, 2018 in WiresClimateChange


Over the past decades, atoll islands exhibited no widespread sign of physical destabilization in the face of sea‐level rise. A reanalysis of available data, which cover 30 Pacific and Indian Ocean atolls including 709 islands, reveals that no atoll lost land area and that 88.6% of islands were either stable or increased in area, while only 11.4% contracted. Atoll islands affected by rapid sea‐level rise did not show a distinct behavior compared to islands on other atolls. Island behavior correlated with island size, and no island larger than 10 ha decreased in size.

Study reconstructing ocean warming finds ocean circulation changes may account for significant portion of sea level rise

by Anthony Watts, January 7, 2019 in WUWT


Study suggests that in the last 60 years up to half the observed warming and associated sea level rise in low- and mid- latitudes of the Atlantic Ocean is due to changes in ocean circulation.

Over the past century, increased greenhouse gas emissions have given rise to an excess of energy in the Earth system. More than 90% of this excess energy has been absorbed by the ocean, leading to increased ocean temperatures and associated sea level rise, while moderating surface warming.

The multi-disciplinary team of scientists have published estimates in PNAS, that global warming of the oceans of 436 x 1021 Joules has occurred from 1871 to present (roughly 1000 times annual worldwide human primary energy consumption) and that comparable warming happened over the periods 1920-1945 and 1990-2015.

“Terrifying Sea-Level Prediction Now Looks Far Less Likely”… But “marine ice-cliff instability” is “just common sense”

by David Middleton, January 5, 2019 in WUWT


Marine ice cliff instability (MICI) “has not been observed, not at such a scale,” “might simply be a product of running a computer model of ice physics at a too-low resolution,” ignores post glacial rebound, couldn’t occur before ” until 2250 or 2300″… Yet “the idea is cinematic,” “it’s just common sense that Antarctic glaciers will develop problematic ice cliffs” and something we should plan for…

“Our results support growing evidence that calving glaciers are particularly sensitive to climate change.”  Greenland’s climate is always changing… Always has and always will change… And the climate changes observed over the last few decades are not unprecedented. The Greenland ice sheet is no more disappearing this year than it was last year and it is physically impossible for the ice sheet to “collapse” into the ocean.

Figure 6. Jakobshavn Isbrae. (Wikipedia and Google Earth)

Sea level oscillations in Japan and China since the start of the 20th century and consequences for coastal management – Part 1: Japan Author links open overlay panel

by Albert Parker, March 1, 2019 in Ocean&CoastalManagement


Highlights
• Japan has strong quasi-20 and quasi-60 years low frequencies sea level fluctuations.
• These periodicities translate in specific length requirements of tide gauge records.
• 1894/1906 to present, there is no sea level acceleration in the 5 long-term stations.
• Those not affected by crustal movement (4 of 5) do not even show a rising trend.
Proper consideration of the natural oscillations should inform coastal planning.

See also here

Land motion drives varying rates of sea level along the US East Coast

by Charles the moderator, December 26, 2018 in WUWT


From Science Magazine

Dec 20, 2018

Along the US East Coast, the Earth’s continued response to the end of the last ice age explains variances in relative sea level rates

Chestnut Hill, Mass. (12/20/2018) – Along the East Coast of the United States, relative sea level change does not happen uniformly between Maine and Florida.

Data have shown that sea level rise in the Mid-Atlantic region surpassed changes in relative sea level along the coastlines of the South Atlantic and the Gulf of Maine. A team of researchers took a look back at historical data through new analytical methods to pinpoint the reason behind the different rates of sea level change.

Assessing data from a range of sources and previous studies, the team concluded that the movement of the earth – referred to as vertical land motion – is the dominant force behind variations in rates of sea level rise up and down the East Coast, the team reports today in the journal Nature.

Is the Pacific island nation of Tuvalu growing, and not sinking, as Craig Kelly says?

by RMIT ABC fact Check, December 21, 2018


The claim

Liberal MP and climate sceptic Craig Kelly made headlines in November when he was caught on tape mocking “lefties” for exaggerating the effects of climate change.

Speaking at a local party event, audio of which was leaked to the Guardian, Mr Kelly set out to debunk several justifications for climate change action, including the argument that Tuvalu, the Pacific island nation, was slipping beneath the sea.

“The science tells us that Tuvalu, which I often hear about, is actually growing not sinking,” he told colleagues.

Is Tuvalu growing? RMIT ABC Fact Check investigates.

The verdict

Mr Kelly’s claim checks out.

In the four decades to 2014, Tuvalu’s total land area grew by 73 hectares, or 2.9 per cent.

The clever ruse of rising sea levels

by J.  Lehr & T. Harris, December 6, 2018 in WUWT


For the past 50 years, scientists have been studying climate change and the possibility of related sea level changes resulting from melting ice and warming oceans. Despite the common belief that increasing levels of carbon dioxide (CO2) in our atmosphere could result in catastrophic sea level rise, there is no evidence to support this fear. Tax monies spent trying to solve this non-existent problem are a complete waste.

Sea level rise: what’s the worst case?

by Judith Curry, November 30, 2018 in WUWT


Draft of article to be submitted for journal publication.

Well, I hope you are not overdosing on the issue of sea level rise.  But this paper is somewhat different, a philosophy of science paper.  Sort of how we think about thinking.

I would appreciate any comments, as well as suggestions as to which journals I might submit to.  I have two in mind, but am open to suggestions (and I may need backups).

Thanks in advance for your comments.

Sea level rise: What’s the worst case?

Abstract. The objective of this paper is to provide a broader framing for how we bound possible scenarios for 21st century sea level rise, in particular how we assess and reason about worst-case scenarios. This paper integrates climate science with broader perspectives from the fields of philosophy of science and risk management. Modal logic is used as a basis for describing construction of the scenario range, including modal inductivism and falsification. The logic of partial positions and strategies for speculating on black swan events associated with sea level rise are described. The rapidly advancing front of background knowledge is described in terms of how we extend partial positions and approach falsifying extreme scenarios of 21st century atmospheric CO2 concentrations, warming and sea level rise. The application of partial positions and worst-case scenarios in decision making strategies is described for examples having different sensitivities to Type I versus Type II errors.

Special Report on Sea Level Rise

by Judith Curry, November 27, 2018 in ClimateEtc.


I have now completed my assessment of sea level rise and climate change.

The complete report can be downloaded here [Special Report- Sea Level Rise  ].

My preliminary compilation of information was provided in the 7 part Climate Etc. series Sea level rise acceleration (or not).

This report reflects 18 months of work on this topic. Why have I devoted so much time to the sea level rise issue? First, I regard sea level rise to be the most consequential potential impact of predicted global warming. Second, there is a great deal of public confusion about the issue, including decision makers. Third, a number of CFAN’s clients have queried me about a range of specific concerns that they have regarding sea level rise (and I have been doing consulting on this topic).

Why do I think an independent assessment of the sea level rise issue by yours truly is needed, given the plethora of international and national assessment reports? My clients are concerned about the alarmist predictions they have encountered. I have seen various ‘experts’ make public statements projecting 21stcentury sea level to be as high as 9 m [30 feet]. My clients are looking for someone that they trust to provide an objective assessment that focuses on their issues of concern.

Climate Alarmism Dies In 2018 As Modern Ice Melt, Sea Level Rise Has No Net Impact On World’s Coasts

by Kenneth Richard, November 15, 2018 in NoTricksZone


The year 2018 could mark the beginning of the end of climate change alarmist reporting.  Projections of catastrophic melting of the ice sheets and sea level rise swallowing up the Earth’s coasts are increasingly undermined by observation.

Despite the hackneyed practice of reporting “staggering” ice sheet melt for both Greenland and Antarctica in recent decades, the two polar ice sheets combined to add just 1.5 centimeters to sea level rise between 1958 and 2014 (graphfrom Frederikse et al., 2018) as global sea levels only rose by “1.5 ± 0.2 mm yr−1 over 1958–2014 (1σ)” or “1.3 ± 0.1 mm yr−1 for the sum of contributors”.

That’s about 7.8 centimeters (3.1 inches) of global sea level change in 56 years.

Hothouse claims from ‘Trajectories of the Earth System in the Anthropocene’ are in a virtual world, not the real world

by Albert Parker, November 2, 2018 in WUWT


A recent paper Trajectories of the Earth System in the Anthropocene (Ref. [1] below) claims that even if the CO2 emission reductions called for in the Paris Agreement are met, our Earth may still enter what they call “Hothouse Earth” conditions, a long-term stabilization at temperature 4-5 °C-higher than pre-industrial temperatures, and sea-level 10-60 m-higher than today. They conclude calling for an accelerated transition towards a CO2 emission-free-world-economy. There is, however, very little evidence that the apocalyptic prediction is scientific grounded. Where really measured, the temperatures haven’t increased dramatically, and similarly, the sea-levels haven’t risen dramatically. More importantly, any acceleration of the temperature warming, or any acceleration of the rate of rise of the sea-level, are hard to detect.

Figure 1 –sample long-term-trend thermometer results (Alice Spring, NT, Australia). The temperatures were recorded in the Post Office / City and Airport locations. Data downloaded from www.bom.gov.au/climate/data/.