Archives par mot-clé : Sea level

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/.

 

Climate Study: 90 Percent Of Atolls And Islands Either Stable Or Growing

by J. Delingpole, October 30, 2018 in ClimateChangeDispatch


Another global warming scare story bites the dust: fragile islands and atolls in the Pacific are not sinking beneath the waves because of global warming. In fact, they are doing just fine.

The bad news (only bad for alarmists, of course) comes in a study by Virginie Duvat of the University of La Rochelle-CNRS, France, titled ‘A global assessment of atoll island planform changes over the past decades’.

It surveyed 30 Pacific and Indian Ocean atolls, including 709 islands, and found that 90 percent have either remained stable or have grown in the last few decades.

CNN: “Climate change endangers dozens of World Heritage sites”… Unmitigated horst schist

by David Middleton, October 19, 2018 in WUWT


Holocene Sea Level

I didn’t take the time to look up the dates of these World Heritage sites… But I’m going to guess they’re OLD.  Many of them probably date back to the Early to Mid-Holocene.  [My bad… That was a bad guess.  The Late Holocene (Meghalayan Age) begins in 4200 BP (2250 BC)]  Here’s a Holocene sea level reconstruction for the Arabian Gulf, with a recent reconstruction of global sea level since 1800 (Jevrejeva et al., 2014) and the satellite sea level trend from CU…

1989 UN report: ‘By 2000, coastal cities will be underwater’

by David Hilton, September 30, 2018 in EndtimesHerald


By the year 2000, according to the 1989 story:

Coastal flooding and crop failures would create an exodus of ″eco- refugees,′ ′ threatening political chaos, said Noel Brown, director of the New York office of the U.N. Environment Program, or UNEP.

He said governments have a 10-year window of opportunity to solve the greenhouse effect before it goes beyond human control.

Well we’re here in 2018, Noel, it’s nearly October, and I’m sitting here in South-East Queensland at midday in a jacket because it’s cold.

Sea Level Speculation Irresponsibly Threatens Property Owners

by Jim Steele, September 26, 2018 in WUWT


The suggested steady 3.3 mm/year rise since 1992 conflicted with CO2-driven model predictions of acceleration. So, based on the difficulties of calibrating altimetry with tide gauge data, various researchers claimed satellite drift and biases had over-estimated early estimates of sea level rise from 1994-2002. Various adjustments were then evoked, and varying rates of sea level rise published. New global sea level estimates rose at an accelerating rate from 1.8 in 1993 to 3.9 mm/yr today, others at 2.2 mm/yr in 1993 to 3.3 mm/yr in 2014, yet others found satellite adjustments lowered the average rate of sea level rise to 2.6 mm/yr over that same period. Elsewhere Harvard geophysicists were analyzing the effects of mass change on the earth’s rotation and wobble and were disturbed by the misfit between geophysical observations and sea level estimates. They argued that only if 20thcentury sea level rise was limited to 1.2 mm/yr could there be a good fit with geophysical expectations.