Sea Level Rise Accelerating

[salbers]

A recent PNAS paper shows SLR is accelerating at .08mm/yr^2. One can look at the doubling time of each component and there we see Antarctic Ice Sheets have a relatively low contribution now, though the shortest doubling time, on the order of 6 years. The overall doubling rate of the rise is roughly 35 years.

http://www.pnas.org/content/early/2018/02/06/1717312115

[Andre Koelewijn]

Still, the rather conservative value of 65 cm rise by the year 2100.

[salbers]

Indeed the 65cm value is a reasonable estimate of a simple quadratic extrapolation. One might also calculate a quadratic estimate of each component. Then the sum of the total will no longer be quadratic. The Antarctic component doubling each 6 years would come to dominate and the total value by 2100 seems it could be more than 65cm.

[vox_mundi]

Modest Warming Risks 'Irreversible' Ice Sheet Loss

Scientists have known for decades that the ice sheets of Greenland and Antarctica are shrinking, but it had been assumed that they would survive a 1.5-2C temperature rise relatively intact.

However, according to a new analysis published in the journal Nature Climate Change, even modest global warming could cause irreversible damage to the polar ice, contributing to catastrophic sea level rises.

"We say that 1.5-2C is close to the limit for which more dramatic effects may be expected from the ice sheets," Frank Pattyn, head of the department of geosciences, Free University of Brussels and lead study author, told AFP.

 Many models of the 1.5-2C scenario allow for the threshold to be breached in the short term, potentially heating the planet several degrees higher, before using carbon capture and other technologies to bring temperatures back into line by 2100.

The study warned against this approach, however, saying that a feedback loop set off by higher temperatures would "lead to self-sustained melting of the entire ice sheet" even if those rises were later offset.

For Greenland, the team said with 95 percent certainty that major ice sheet decline would occur at 1.8C worth of warming.

"For both Greenland and Antarctica, tipping points are known to exist for warming levels that could be reached before the end of this century," said Pattyn.

The Greenland and Antarctic ice sheets under 1.5 °C global warming, Nature Climate Change (2018

[wili]

https://www.axios.com/sea-level-rise-will-be-costly-if-we-dont-take-action-8d63cf4a-db07-4512-a97b-5718920aaa38.html

Rising sea levels could cost the U.S. trillions

Andrew Freedman

...parts of Antarctica are far less stable than previously thought. That's why its sea level rise projections are higher than prior reports from the...IPCC...

[wolfpack513]

It has been mention a lot but once the selling starts for coastal properties it’s going to get bad.  People will lose equity/savings and that of course will impact the greater economy.  You don’t want to be the last house on the block to put the “for sale” sign up.  This alone will be trillions before the water rises.

[KiwiGriff]

Global sea level rise began to accelerate in the 1960s, 30 years earlier than suggested by previous assessments, a new study finds.

Previous studies reconstructed twentieth-century global mean sea level (GMSL) from sparse tide-gauge records to understand whether the recent high rates obtained from satellite altimetry are part of a longer-term acceleration. However, these analyses used techniques that can only accurately capture either the trend or the variability in GMSL, but not both. Here we present an improved hybrid sea-level reconstruction during 1900–2015 that combines previous techniques at time scales where they perform best. We find a persistent acceleration in GMSL since the 1960s and demonstrate that this is largely (~76%) associated with sea-level changes in the Indo-Pacific and South Atlantic. We show that the initiation of the acceleration in the 1960s is tightly linked to an intensification and a basin-scale equatorward shift of Southern Hemispheric westerlies, leading to increased ocean heat uptake, and hence greater rates of GMSL rise, through changes in the circulation of the Southern Ocean.

https://www.nature.com/articles/s41558-019-0531-8

[Klondike Kat]

According to his analysis, continued acceleration in SLR would reach ~10 mm/year by 2100, resulting in a total additional rise of about half a meter.

[Juan C. García]

This is an article about the gravitational pull of Greenland. I also included a NASA video that shows the lowering of sea levels around Greenland as the ice cap melts, and the gravitational pull weakens. This could also maybe explain why sea levels in Ireland are going up?

Gravitational Attraction of Ice Sheets on the Sea
http://sealevelstudy.org/sea-change-science/whats-in-a-number/attractive-ice-sheets

Great post of Freegrass.
I think that it should be also posted here.

Links to the video:
NASA: https://sealevel.nasa.gov/resources/78/monthly-changes-in-gravity-affect-sea-level
Youtube:

[Tom_Mazanec]

Shoreline industry poses hazards as sea level, floods increase
https://www.bayjournal.com/article/shoreline_industry_poses_hazards_as_sea_level_floods_increase

But with the Earth warming and sea level rising, many riverside clusters of industry are ground zero for rising waters — posing a new risk for the environment and those living nearby.

In a report issued this spring, the Center for Progressive Reform finds that almost 1,100 industrial facilities in Virginia’s James River watershed that use state or federally regulated chemicals are exposed to both potential flooding and projected sea level rise. Worse, they are located in socially vulnerable communities where residents have the fewest resources to escape a disaster’s effects.

[Tom_Mazanec]

15 To 20 Foot Sea Level Rise Possible Sooner Rather Than Later
https://cleantechnica.com/2019/09/13/15-to-20-foot-sea-level-rise-possible-sooner-rather-than-later/

Why is Alley’s threat assessment greater than the people who are preparing reports for IPCC? Bureaucracy, mostly. They are written in collaboration with a large group of scientists and are often watered down by endless debate and consensus-building. In total there are 18 lead authors and 69 contributing authors on the chapter that considers sea-level rise. Also, by the time the final reports are written, the underlying data is often not the most current available.

[sidd]

AGU has the GRACE/GRACE-FO talk online now. I just watched Velicogna on land ice loss.

highlights:

GIS: ice loss of 600GT in 2019, like in 2012, steady decline 250 GT/yr
AIS; Amundsen, Wilkes land sustain decline since 2001, Queen Maud land sustained increase since 2009, Peninsula decline till 2016, then increase from snowfall in 2016, back to decline now. Pause in acceleration today, this has been seen before. Slodown in overall mass loss since 2016
Other glaciers,ice caps, Himalayas: 250GT/yr mass loss

Have to register at AGU fall meet website. Chekitout.

sidd

[Hefaistos]

Not so much SLR in the Pacific though, by considering the average of 29 tide gauges included in the Japan-5, Oceania-4 and West Coast of North America-20 data sets, both the relative rate of rise and the acceleration are negative, i.e this report shows deceleration.

"Conclusion
The Pacific Atolls are not drowning because the sea level is rising much less than what was once thought. By considering the average of the 29 long-term-trend (LTT) tide gauges of Japan, Oceania and West Coast of North America, both the relative rate of rise and acceleration are negative, −0.02139 mm yr−1 and −0.00007 mm yr−2, respectively. Since the start of the 1900s, the sea levels of the Pacific have been remarkably stable, rising or falling mostly because of subsidence. The evidence proposed by Duvat (2018) is supported by the long-term tide gauge indication."

https://content.sciendo.com/configurable/contentpage/journals$002fquageo$002f38$002f1$002farticle-p179.xml

/link above broken, must copy missing part manually/

See also "A global assessment of atoll island planform changes over the past decades" by
Virginie K. E. Duvat, 2018.
https://onlinelibrary.wiley.com/doi/abs/10.1002/wcc.557

Maybe we have SLR acceleration in some Seas, and deceleration in others?

[gerontocrat]

And so it goes on

28 Trillion tons of ice gone from 1994 to 2017.
If its all in the sea that's nearly 8 cms sea level rise.
EDIT: Whoops, But it isn't - 54% of ice loss issea ice and floating ice shelves.
So that's about 3.5 cms of actual sea level rise to 2017 & about 4cms by end 2020.

At 1.2 trillion tons per annum that's 31 trillion tons by end 2020 - nearly 9cms.

ADDENDUM
Every year global ocean heat content rises on average by just over 1 x 10^²² joules of energy.
That is enough to melt all those circa 30,000 cubic kilometers of ice melted from 1994 to the present - with a little bit of energy left over.


https://www.theguardian.com/environment/2020/aug/23/earth-lost-28-trillion-tonnes-ice-30-years-global-warming
Earth has lost 28 trillion tonnes of ice in less than 30 years

The scientists – based at Leeds and Edinburgh universities and University College London – describe the level of ice loss as “staggering” and warn that their analysis indicates that sea level rises, triggered by melting glaciers and ice sheets, could reach a metre by the end of the century.

“To put that in context, every centimetre of sea level rise means about a million people will be displaced from their low-lying homelands,” said Professor Andy Shepherd, director of Leeds University’s Centre for Polar Observation and Modelling.

The level of ice loss revealed by the group matches the worst-case-scenario predictions outlined by the Intergovernmental Panel on Climate Change (IPCC), he added.

https://tc.copernicus.org/preprints/tc-2020-232/
Review Article: Earth's ice imbalance

Abstract.
We combine satellite observations and numerical models to show that Earth lost 28 trillion tonnes of ice between 1994 and 2017. Arctic sea ice (7.6 trillion tonnes), Antarctic ice shelves (6.5 trillion tonnes), mountain glaciers (6.2 trillion tonnes), the Greenland ice sheet (3.8 trillion tonnes), the Antarctic ice sheet (2.5 trillion tonnes), and Southern Ocean sea ice (0.9 trillion tonnes) have all decreased in mass. Just over half (60 %) of the ice loss was from the northern hemisphere, and the remainder (40 %) was from the southern hemisphere.

The rate of ice loss has risen by 57 % since the 1990s – from 0.8 to 1.2 trillion tonnes per year – owing to increased losses from mountain glaciers, Antarctica, Greenland, and from Antarctic ice shelves. During the same period, the loss of grounded ice from the Antarctic and Greenland ice sheets and mountain glaciers raised the global sea level by 35.0 ± 3.2 mm.

The majority of all ice losses were driven by atmospheric melting (68 % from Arctic sea ice, mountain glaciers ice shelf calving and ice sheet surface mass balance), with the remaining losses (32 % from ice sheet discharge and ice shelf thinning) being driven by oceanic melting.

Altogether, the cryosphere has taken up 3.2 % of the global energy imbalance.

[Tom_Mazanec]

At 1.2 trillion tons per annum that's 31 trillion tons by end 2020 - nearly 9cms.

But it will almost certainly be much more than that later in the century.

[KiwiGriff]

The Paper Hefaistos just linked to is by a well known crank.
 Albert Parker/ Alberto Boretti
Being a member of  Principia Scientific International he is a fuckin gibbering loon class crank.
 https://www.desmogblog.com/albert-parker

[oren]

I was wondering about that paper but did not have time to follow through.
I guess the quest to show AGW isn't as bad as feared takes one to dark places.

[oren]

Here is some non-cherry-picked data about sea level rise.

[Hefaistos]

The Paper Hefaistos just linked to is by a well known crank.
 Albert Parker/ Alberto Boretti
Being a member of  Principia Scientific International he is a fuckin gibbering loon class crank.
 https://www.desmogblog.com/albert-parker

Sorry for not checking their credentials!
I'm more focused on research and results, than on the people behind the research. Never heard of Parker or Boretti before.

However, their data seem to be correct. If you compare with the map with sampling stations that oren just posted it seems there is no conflict, as their data mainly came from Japan and the US.
Good to have the more complete picture.

[Hefaistos]

Here is some non-cherry-picked data about sea level rise.

Thanks oren!
The last two charts, is that global data, or for the Pacific?

[ArcticMelt2]

Indeed the 65cm value is a reasonable estimate of a simple quadratic extrapolation. One might also calculate a quadratic estimate of each component. Then the sum of the total will no longer be quadratic. The Antarctic component doubling each 6 years would come to dominate and the total value by 2100 seems it could be more than 65cm.

I agree. A doubling of the rate of ice melting can occur every 10-15 years.

[oren]

Here is some non-cherry-picked data about sea level rise.

Thanks oren!
The last two charts, is that global data, or for the Pacific?

Both global.
These are just taken from Wikipedia ("sea level" and "sea level rise") and did not need much searching at all. The research you posted did not pass the sniff test and should not have passed yours either. Sea level rise is an undeniable fact. I believe the denier source both cherry-picked the specific region, AND twisted the data, from the little I could understand of their methods from the poorly written and obfuscating paper. In addition most of the references point to articles by the same authors, and other references' conclusions are twisted to fit the central narrative. You would do well to stay away from such sources and perform better checks when the conclusions are suspicious.

[ArcticMelt2]

Still, the rather conservative value of 65 cm rise by the year 2100.

For the United States, say half a meter by 2050.

https://www.eurekalert.org/pub_releases/2020-02/viom-usr020320.php

In some places it will be even higher.

The three highest rates of sea-level rise in 2019 occurred along the Gulf Coast at Grand Isle, Louisiana (7.93 millimeters per year) and at Rockport (6.95 mm/yr) and Galveston (6.41 mm/yr) Texas. Rockport also topped all 32 stations in its rate of acceleration, at 0.26 mm per year per year. If this continues, sea level here will be 0.82 meters (2.69 feet) higher in 2050 compared to 1992.

[S.Pansa]

Talking about the methods of Parker/Boretti . Tamino has more insight on some of them here & here - (simply making stuff up, etc).

Apart from the scientific methods, Parker/Boretti are obviously one and the same person.
From Tamino" You see, Albert Parker also goes by the name Alberto Boretti."

Thankfully this kind of science gets no soil to flourish here.

[Tom_Mazanec]

Interesting post, oren.
The map seems to show near zero SLR for LA but quite a bit for Miami. Interesting.

[Simon]

For an overall view of sea level rise, the Americans have a good site here:

https://www.climate.gov/news-features/understanding-climate/climate-change-global-sea-level

[wili]

As I recall, sea level rise is (counter-intuitively) faster on the US east coast than many other places because the 'Gulf Stream' is predicted to move closer to shore, bringing its (bernoulli effect?) bulge with it.

Some areas, of course, are also in the long-term process of sinking, including Florida, but at a much slower rate than the sea is rising.

https://www.theinvadingsea.com/2020/03/19/yes-the-land-is-slowly-sinking-in-parts-of-florida-but-the-sea-is-rising-much-faster-and-poses-a-far-greater-threat-of-flooding/

[sidd]

von Schuckmann has a review out on earth energy imbalance and accumulation of heat in the oceans:

"The study obtains a consistent long-term Earth system heat gain over the period 1971–2018, with a total heat gain of 358±37 ZJ, which is equivalent to a global heating rate of 0.47±0.1 W m−2. Over the period 1971–2018 (2010–2018), the majority of heat gain is reported for the global ocean with 89 % (90 %), with 52 % for both periods in the upper 700 m depth, 28 % (30 %) for the 700–2000 m depth layer and 9 % (8 %) below 2000 m depth. Heat gain over land amounts to 6 % (5 %) over these periods, 4 % (3 %) is available for the melting of grounded and floating ice, and 1 % (2 %) is available for atmospheric warming. Our results also show that EEI is not only continuing, but also increasing: the EEI amounts to 0.87±0.12 W m−2during 2010–2018. Stabilization of climate, the goal of the universally agreed United Nations Framework Convention on Climate Change (UNFCCC) in 1992 and the Paris Agreement in 2015, requires that EEI be reduced to approximately zero to achieve Earth’s system quasi-equilibrium. The amount of CO2 in theatmosphere would need to be reduced from 410 to 353 ppm to increase heat radiation to space by 0.87 W m−2, bringing Earth back towards energy balance."

"Our results show that EEIis not only continuing, but also increasing. Over the period 1971–2018 average EEI amounts to 0.47±0.1 W m−2, but it amounts to 0.87±0.12 W m−2 during 2010–2018 (Fig. 8).Concurrently,  acceleration  of  sea-level  rise  (WCRP,  2018;Legelais et al., 2020), accelerated surface warming, record temperatures and sea ice loss in the Arctic (Richter-Mengeet al., 2019; WMO, 2020; Blunden and Arndt, 2020) and ice loss  from  the  Greenland  ice  sheet  (King  et  al.,  2020),  and intensification of atmospheric warming near the surface and in the troposphere (Steiner et al., 2020) have been – for example – recently reported. To what degree these changes are intrinsically linked needs further evaluations"

doi: 10.5194/essd-12-2013-2020

open access, read all about it. Worth it for the references alone. Earth energy imbalance and OHC continue increasing.

sidd

[Richard Rathbone]

I was wondering which thread this one should go in.

Its pretty much impossible for increasing EEI not to accelerate sea level rise.

Hansen has suggested a feedback where increased ice cap melt leads to increased EEI, I wonder if this is contributing to the higher EEI in the 2010s.

The 350ppm stablised climate seems to be getting hotter as well as requiring more CO2 removal to achieve it.

[FishOutofWater]

Gulf Stream slowdown contributes to SLR on the SE coast of the U.S. Compaction driven subsidence is a major factor in apparent SLR in coastal Louisiana.

Hansen's papers discussed melt driven slowdowns in deep water formation in both hemispheres contributing to ocean heat build up. That started years ago and certainly got going strong in 2010.

Arctic ice loss is affecting the whole NH climate. The polar vortex weakens when warm water moves into the Barents sea. This winter should be very weird very likely with a weak vortex.