Sea Level Rise Projections and Maps

[Sebastian Jones]

Theoretically, there is kind of progressions which have a limit but don't have a maximum.

You really think he meant that the human population will approach an asymptote?!

"Fortunately" we still have the catastrophic effects of the climate crisis to counter the potential for an asymptotic population trend....

[oren]

I think KK meant medical breakthroughs could modify the expected trajectory of human population, preventing the expected peaking, increasing pressure on the environment, and thus bringing about sharp sea level rise much sooner. Hope I understood correctly.
Population will off course peak due to the adverse results of climate change and the rest of the carrying capacity issues. The higher you fly, the faster you fall.

[bligh8]

Re:  The higher you fly, the faster you fall.

Terminal velocity for humans is about 240kph, so if one is falling over salt water with SLR in mind one would go splat somewhat sooner.

[Tom_Mazanec]

I'll repost my link to the model of Earth 3000 AD ("Dubia") here because I realized this is where it really belonged:
http://www.worlddreambank.org/D/DUBIA.HTM

[bbr2314]

I'll repost my link to the model of Earth 3000 AD ("Dubia") here because I realized this is where it really belonged:
http://www.worlddreambank.org/D/DUBIA.HTM

Melting 100% of Greenland by 3000AD would require approximately .1% losses each year (based on current mass balance). That would mean that the entirety of the SMB loss between 2002 and 2019, which I believe to be .1%, would be repeated EACH AND EVERY YEAR. That is a loss of 4,000 GT a year of ice, approximately 15X the mass loss we see each year today.

I feel like the impacts of such MASSIVE ice loss are always lost in these projections. If the changes since 2002 -- and 2012 in particular -- are enough to result in changes we have seen to date, a melt year where Greenland loses 2X the volume of its record loss year to date is going to potentially have exponentially worse impacts than what we have already witnessed. Even if the impacts aren't exponential, at what threshold does mass loss result in year without a summer for much of the NATL? 3X current worst to date? 4X? 5? 10X? 20X? Because if projections are correct we are going to hit each and every one of those numbers at some point in the relatively near future. And I do not believe that will be without dire consequence that temporarily halts or stalls the melting of the ice sheet (the only good result).

[vox_mundi]

Stability Check on Antarctica Reveals High Risk for Long-Term Sea-Level Rise
https://phys.org/news/2020-09-stability-antarctica-reveals-high-long-term.amp

The warmer it gets, the faster Antarctica loses ice - and much of it will then be gone forever. Consequences for the world's coastal cities and cultural heritage sites would be detrimental, from London to Mumbai, and from New York to Shanghai. That's what a team of researchers from the Potsdam Institute for Climate Impact Research, Potsdam University and New York's Columbia University has found out in their new study, published in Nature (cover story), on how much warming the Antarctic Ice Sheet can survive.

... "As the surrounding ocean water and atmosphere warm due to human greenhouse-gas emissions, the white cap on the South Pole loses mass and eventually becomes unstable. Because of its sheer magnitude, Antarctica's potential for sea-level contribution is enormous: We find that already at 2 degrees of warming, melting and the accelerated ice flow into the ocean will, eventually, entail 2.5 meters of global sea level rise just from Antarctica alone. At 4 degrees, it will be 6.5 meters and at 6 degrees almost 12 meters if these temperature levels would be sustained long enough."

Long-term change: it's not rapid, but it's forever

"Antarctica is basically our ultimate heritage from an earlier time in Earth's history. It's been around for roughly 34 million years. Now, our simulations show that once it's melted, it does not regrow to its initial state even if temperatures eventually sink again. Indeed, temperatures would have to go back to pre-industrial levels to allow its full recovery—a highly unlikely scenario. In other words: What we lose of Antarctica now is lost forever."



The animation shows the modelled long-term evolution of the Antarctic Ice Sheet under steadily increasing temperatures.

The upper panel shows the ice sheet's surface elevation change (in meters; grey shading), the ocean-induced melting at the base of the floating ice shelves (in meters per year; purple-orange shading), as well as the topography of the bed underneath the ice sheet and the surrounding ocean (in meters above the present-day sea level; blue-brown shading).

The lower panel shows the total sea-level relevant ice volume change (in meters of sea-level equivalent ; blue curve) and total ice mass flux (in gigatons per year; purple curve).

The hysteresis of the Antarctic Ice Sheet, Nature (2020).
https://www.nature.com/articles/s41586-020-2727-5

[morganism]

The transient sensitivity of sea level rise

https://os.copernicus.org/articles/17/181/2021/#:~:text=We%20define%20a%20new%20transient,temperature%20increases%20on%20this%20timescale.


"By analyzing the mean rate of change in sea level (not sea level itself), we identify a nearly linear relationship with global mean surface temperature (and therefore accumulated carbon dioxide emissions) both in model projections and in observations on a century scale. "

"Historical sea level exhibits substantially higher sensitivity than model-based estimates of future climates in authoritative climate assessments, implying recent projections could well underestimate the likely sea level rise by the end of this century."

[sidd]

Thats a very nice paper. Grinsted takes a simple model (sea level rise rate proportional to global mean temperature and demonstrates that models are underestimating.

Chekitout. open access.

sidd

[gerontocrat]

A nice article (based on Miami) on how the moon's orbit is currently reducing apparent sea level rise.

https://theconversation.com/this-supermoon-has-a-twist-expect-flooding-but-a-lunar-cycle-is-masking-effects-of-sea-level-rise-158412

This supermoon has a twist – expect flooding, but a lunar cycle is masking effects of sea level rise

Another “super full moon” is coming May 26, 2021, and coastal cities like Miami know that means one thing: a heightened risk of tidal flooding.

Exceptionally high tides are common when the moon is closest to the Earth, known as perigee, and when it’s either full or new. In the case of what’s informally known as a super full moon, it’s both full and at perigee.

But something else is going on with the way the moon orbits the Earth that people should be aware of. It’s called the lunar nodal cycle, and it’s presently hiding a looming risk that can’t be ignored.

Right now, we’re in the phase of an 18.6-year lunar cycle that lessens the moon’s influence on the oceans. The result can make it seem like the coastal flooding risk has leveled off, and that can make sea level rise less obvious.

This simplified chart illustrates how the lunar nodal cycle suppresses and enhances the effects of sea level rise in Miami. The basic model assumes a constant linear increase of sea level, so it doesn’t capture the expected acceleration of sea level rise. Brian McNoldy, CC BY-ND

But communities shouldn’t get complacent. Global sea level is still rising with the warming planet, and that 18.6-year cycle will soon be working against us.

The moon’s orbital plane precesses, or wobbles, to a maximum and minimum of +/- 5 degrees over a period of about 18.6 years. This natural cycle of orbits is called the lunar nodal cycle. When the lunar plane is more closely aligned with the plane of Earth’s equator, tides on Earth are exaggerated. Conversely, when the lunar plane tilts further away from the equatorial plane, tides on Earth are muted, relatively.

The lunar nodal cycle was first formally documented in 1728 but has been known to keen astronomical observers for thousands of years.

What effect does that have on sea level?

The effect of the nodal cycle is gradual – it’s not anything that people would notice unless they pay ridiculously close attention to the precise movement of the moon and the tides for decades.

Once we reach the bottom of the cycle around 2025 and start the upward phase, the lunar nodal cycle begins to contribute more and more to the perceived rate of sea level rise. During those years, the rate of sea level rise is effectively doubled in places like Miami. The impact varies from place to place since the rate of sea level rise and the details of the lunar nodal cycle’s contribution vary.

[The Walrus]

Where did they come up with that 0.23 in/year for SLR?  NASA states 3.3 mm/year over a similar timeframe, which corresponds to 0.13 in/year.  Perhaps a typo?

[gerontocrat]

Where did they come up with that 0.23 in/year for SLR?  NASA states 3.3 mm/year over a similar timeframe, which corresponds to 0.13 in/year.  Perhaps a typo?

It's Miami. SLR varies a lot over the world. US East coast SLR is higher.

https://www.star.nesdis.noaa.gov/socd/lsa/SeaLevelRise/LSA_SLR_maps.php

Laboratory for Satellite Altimetry / Sea Level Rise
Products / Sea level rise maps
The following maps provide estimates of sea level rise based on measurements from satellite radar altimeters. The local trends were estiamted using data from TOPEX/Poseidon (T/P), Jason-1, Jason-2, and Jason-3, which have monitored the same ground track since 1992.

An inverted barometer has been applied. The estimates of sea level rise do not include glacial isostatic adjustment effects on the geoid, which are modeled to be +0.2 to +0.5 mm/year when globally averaged.

click to enlarge image

[oren]

That article is specific to Miami, maybe it includes local effects - Gulf Stream changes, regional ocean warming, ground subsidence, post-glacial effects, and even gravitational effects (locations far from where ice disappears are hit by more relative SLR).

Edit: what Gero said.

[gerontocrat]

A new sea level rise data set from NASA / JPL (see description below) available at

https://podaac-tools.jpl.nasa.gov/drive/files/allData/merged_alt/L2/TP_J1_OSTM/global_mean_sea_level/GMSL_TPJAOS_5.1_199209_202108.txt

Data updated 2 or 3 times per month with about 4 month lag with several columsn for unadjusted and smoothing /  Global Isostatic Adjustment (GIA) adjustments.

You have to register with PO.DACC - they even let me register

Graph attached
_____________________________________________________
Global Mean Sea Level Trend from Integrated Multi-Mission Ocean Altimeters TOPEX/Poseidon, Jason-1, OSTM/Jason-2, and Jason-3 Version 5.1 Dataset Release
Thursday, November 4, 2021
The PO.DAAC is pleased to announce the public release of the Global Mean Sea Level (GMSL) trend Version 5.1 dataset from the Making Earth System Data Records for Use in Research Environments (MEaSUREs) Integrated Multi-Mission Ocean Altimeter Data for Climate Research project. More information about the GMSL dataset is available on the NASA Sea Level website.

The GMSL trend is a 1-dimensional time series of globally averaged Sea Surface Height Anomalies (SSHA) from TOPEX/Poseidon, Jason-1, OSTM/Jason-2, and Jason-3 altimeters that covers September 1992 to present with a latency of up to 4 months. The data are reported as variations relative to a 20-year TOPEX/Jason collinear mean. Bias adjustments and cross-calibrations were applied to ensure SSHA data are consistent across the missions; Glacial Isostatic Adjustment (GIA) was also applied. The data are available as a table in ASCII format.

Version 5.1 incorporates revisions to the orbit height corrections, ocean tide corrections (from a revised internal tide model), and a pole tide correction collectively used to integrate observations from TOPEX/Poseidon, Jason-1, Jason-2 (OSTM), and Jason-3. These changes are described in detail in section two of the user handbook.

This latest version of the GMSL trend produced by MEaSUREs is described and discoverable on the PO.DAAC data portal.

DOI: 10.5067/GMSLM-TJ151

Citation: Beckley, B.; Ray, R.; Zelensky, N.; Lemoine, F.; Yang, X.; Brown, S.; Desai, S.; Mitchum, G.. 2020. Global Mean Sea Level Trend from Integrated Multi-Mission Ocean Altimeters TOPEX/Poseidon Jason-1 and OSTM/Jason-2 Version 5.1. PO.DAAC, CA, USA. https://doi.org/10.5067/GMSLM-TJ151.

Reference: Beckley, B.; Ray, R.; Zelensky, N.; Lemoine, F.; Yang, X.; Brown, S.; Desai, S.; Mitchum, G.. 2020. Integrated Multi-Mission Ocean Altimeter Data for Climate Research TOPEX/Poseidon, Jason-1, 2, & 3 User’s Handbook Version 5.1. PO.DAAC, CA, USA. https://doi.org/10.5067/ALTUG-TJ151.

Comments/Questions? Please contact podaac@podaac.jpl.nasa.gov or visit the PO.DAAC Forum.

[etienne]

Hello Gerontocrat,
Wat are the units of the vertical axis? I didn't find it in your comment.
Thanks,
Étienne

[gerontocrat]

Hello Gerontocrat,
Wat are the units of the vertical axis? I didn't find it in your comment.
Thanks,
Étienne

Whoops - millimetres - graph amended

[vox_mundi]

US Could See a Century's Worth of Sea Rise In Just 30 Years
https://phys.org/news/2022-02-century-worth-sea-years.html

The seas lapping against America's coastlines are rising ever faster and will be 10 to 12 inches higher by the year 2050, with major Eastern cities hit regularly with costly floods even on sunny days, a government report says.

The National Oceanic and Atmospheric Administration and six other federal agencies issued a 111-page report Tuesday that warns of "significant consequences" from rising seas in the next few decades, with parts of Louisiana and Texas projected to see waters a foot and a half (0.45 meters) higher.

Report: https://oceanservice.noaa.gov/hazards/sealevelrise/sealevelrise-tech-report.html

However, the worst of the long-term sea level rise from the melting of ice sheets in Antarctica and Greenland probably won't kick in until after 2100, the study's lead author said.

Because of climate change, the nation's coastlines on average will see as much sea level rise in the next 30 years as they did in the previous century , said lead author William Sweet, an oceanographer for NOAA's National Ocean Service.

The coastal flooding the U.S. is seeing now "will get taken to a whole new level in just a couple of decades."

Sea level rises more in some places than others because of sinking land, currents and water from ice melt. The United States will get slightly more sea level rise than the global average. And the greatest rise in the U.S. will be on the Gulf and East Coasts, while the West Coast and Hawaii will be hit less than average, Sweet said.

For example, between now and 2060, expect almost 25 inches (0.63 meters) of sea level rise in Galveston, Texas, and just under 2 feet (0.6 meters) in St. Petersburg, Florida, while only 9 inches (0.23 inches) in Seattle and 14 inches (0.36 meters) in Los Angeles, the report said.

And that's just until 2050. The report is projecting an average of about 2 feet of sea level rise in the United States—more in the East, less in the West—by the end of the century.

------------------------------------------------

Sea-Level Rise Viewer: https://coast.noaa.gov/slr/#/layer/slr/0/-8140106.020717291/5040443.399307347/16/satellite/none/0.8/2050/interHigh/midAccretion

-------------------------------------------------

Locally; this house used to have 75 feet of frontage to the High Tide line. Also, there's a road in front of that house - between the porch and telephone poles, both of which are underwater.

[Shared Humanity]

US Could See a Century's Worth of Sea Rise In Just 30 Years
https://phys.org/news/2022-02-century-worth-sea-years.html

The Republican governor and Republican led legislature of North Carolina anticipated this and in 2012 passed a law making it illegal for sea level to rise at a rate faster than it had over the previous century.

"These rates shall only be determined using historical data, and these data shall be limited to the time period following the year 1900. Rates of seas-level rise may be extrapolated linearly …"


https://www.theguardian.com/environment/2012/jun/01/north-carolina-sea-level-rises

Or something like that. 

When you don't like what the science is telling you, ignore it and say/do something stupid.

[trm1958]

at about 40:50 gives sea level rise in the last year as i
1 cm. Has SLR actually jumped up this much?

[Bruce Steele]

Tom , The report that Vox linked above predicts about 24”( 61cm ) by 2060 so about 1.7cm per year in Galveston. Less in other places but a current rate of 1cm seems reasonable. Mostly due to thermal expansion of the oceans , 2023 was especially hot so rate may increase.

[gerontocrat]

1 cm. Has SLR actually jumped up this much?

The gold standard for measuring SLR is from NASA - "Global Mean Sea Level Trend from Integrated Multi-Mission Ocean Altimeters TOPEX/Poseidon, Jason-1, OSTM/Jason-2, and Jason-3 Version 5.1" - see details below

They recalculate the values continuously but the changes are relatively minor.
The data I have is only to mid-2023, as they seems to have done a biggish recalculation including removal of preliminary August to November data.

I attach the latest graph. Note the big spikes followed by big drops in 1997-98 & 2015-16, the El Nino effect.

So a 10 mm rise in 2023 would not be a surprise, unless not followed by a big drop.
It does look as if the SLR is accelerating slowly, the trend now at around 4.5 mms per year compared with around 2.5 in the 1990's.

Global Mean Sea Level Data
HDR This file contains Global Mean Sea Level (GMSL) variations computed at the NASA Goddard Space Flight Center under the HDR auspices of the NASA Sea Level Change program. The GMSL was generated using the Integrated Multi-Mission Ocean Altimeter Data.

It combines Sea Surface Heights from the HDR TOPEX/Poseidon, Jason-1, OSTM/Jason-2, Jason-3, and Sentinel-6 Michael Freilich missions to a common terrestrial reference frame with all inter-mission biases, range and HDR geophysical corrections applied and placed onto a georeferenced orbit.  This creates a consistent data record throughout HDR time, regardless of the instrument used. 

Note, the most recent estimates of GMSL (post March 28, 2022) derived from the Sentinel-6 Michael Freilich mission HDR are preliminary as validation and reprocessing procedures for Sentinel-6 are ongoing.

[gerontocrat]

Tom , The report that Vox linked above predicts about 24”( 61cm ) by 2060 so about 1.7cm per year in Galveston. Less in other places but a current rate of 1cm seems reasonable. Mostly due to thermal expansion of the oceans , 2023 was especially hot so rate may increase.

Don't forget land subsidence, though that may be declining (see below)

https://www.nature.com/articles/s41598-020-74696-4

Land subsidence contributions to relative sea level rise at tide gauge Galveston Pier 21, Texas
Abstract
Relative sea level rise at tide gauge Galveston Pier 21, Texas, is the combination of absolute sea level rise and land subsidence. We estimate subsidence rates of 3.53 mm/a during 1909–1937, 6.08 mm/a during 1937–1983, and 3.51 mm/a since 1983. Subsidence attributed to aquifer-system compaction accompanying groundwater extraction contributed as much as 85% of the 0.7 m relative sea level rise since 1909, and an additional 1.9 m is projected by 2100, with contributions from land subsidence declining from 30 to 10% over the projection interval.

[morganism]

 Sea Level Rise in California   (pdf @ site)

Sea levels are rising due to increasing temperatures from climate change.

    As the atmosphere warms, ocean water warms—causing the water to expand—and land-based ice melts. Both of these processes raise sea level.
    Future sea level rise is inevitable, as greenhouse gases (GHGs) already in the atmosphere continue to trap heat. Reducing GHG emissions in the coming decades would reduce the rate of sea level rise in the long term.
    The rate of sea level rise will also depend on whether large ice sheets melt steadily or collapse rapidly. Recent evidence suggests that ice sheets are melting faster than expected, which could lead to more rapid sea level rise.

Californians are already impacted by sea level rise, and it is getting worse.

    California has experienced about 8 inches of sea level rise over the past century, and this pace will accelerate after 2050. Many areas along California’s coast already flood on a regular basis, and low-income communities of color are particularly impacted.
    One- to two-thirds (31–67%) of Southern California beaches may completely erode by 2100 without costly, large-scale interventions like breakwaters and beach nourishment. Such investments can be expensive and may cause erosion or other negative environmental impacts.
    Assuming high GHG emissions continue, the state of California recommends preparing for 1–6.6 feet of sea level rise by 2100.

https://www.ppic.org/publication/sea-level-rise-in-california/

[gerontocrat]

https://search.earthdata.nasa.gov/search/granules?p=C2205556193-POCLOUD&pg[0][v]=f&pg[0][gsk]=-start_date&q=sea%20level%20rise&ff=Available%20in%20Earthdata%20Cloud&tl=1665594246!3!!

NASA has published sea level rise (SLR) data to early July 2024.

The attached graph shows how annual SLR increases as an El Nino takes hold and declines as the switch to ENSO Neutral and La Nina takes place. When we get an update of ocean heat content for Qu2 2024 we might see a parallel trend in ocean heat content changes. I wish we had some more up-to-date GIS and AIS mass loss data, but both JPL and GFZ have not published updated GRACE-FO data for several months.

The data suggests that the longterm linear trend in annual SLR has increased from 2.5 mm to 5 mm in the last 30 years.

[gerontocrat]

NASA has published sea level rise (SLR) data to early August2024.

The attached graph shows clearly how annual SLR increases as an El Nino takes hold and declines as the switch to ENSO Neutral and La Nina takes place. When we get an update of ocean heat content for Qu2 2024 we might see a parallel trend in ocean heat content changes. I wish we had some more up-to-date GIS and AIS mass loss data, but both JPL and GFZ have not published updated GRACE-FO data for many months.

The data continues to suggest that the longterm linear trend in annual SLR increase has accelerated from +2.5 mm to +5 mm in the last 30 years.

[morganism]

Communications Earth & Environment @CommsEarth

Global mean #sea level rise amounted to 4.5 mm per year as a result of #warming oceans and melting land ice, more than twice the rate of 2.1 mm/year observed at the start of satellite data in 1993.

....
The rate of global sea level rise doubled during the past three decades

https://www.nature.com/articles/s43247-024-01761-5

The rise in globally averaged sea level—or global mean sea level—is one of the most unambiguous indicators of climate change. Over the past three decades, satellites have provided continuous, accurate measurements of sea level on near-global scales. Here, we show that since satellites began observing sea surface heights in 1993 until the end of 2023, global mean sea level has risen by 111 mm. In addition, the rate of global mean sea level rise over those three decades has increased from ~2.1 mm/year in 1993 to ~4.5 mm/year in 2023. If this trajectory of sea level rise continues over the next three decades, sea levels will increase by an additional 169 mm globally, comparable to mid-range sea level projections from the IPCC AR6.

[gerontocrat]

NASA has published sea level rise (SLR) data to mid-September 2024.

The attached graph shows clearly how annual SLR increases as an El Nino takes hold and declines quickly as the switch to ENSO Neutral and La Nina takes place. It has been impressive - a 7 mm drop in SLR from early June 24, i.e. in just three and a half months.
It must mean a lot of heat leaving the ocean into the atmosphere ?

Perhaps Qu3 Ocean heat data will give the answer. Should be issued in a month or so.

[Downpuppy]

This part of Nantucket is losing about 4 meters of beach per year. The picture is from the Boston Globe, & shows plots of land now underwater, which seemed interesting. If you own underwater land, do you retain any rights? The article is mostly about houses facing doom that are becoming unsellable.

[Richard Rathbone]

In England there are separate rights for land and tidal areas, and if the boundary between land and tidal area changes, generally the ownership moves with the boundary. So whoever had rights to the tidal area would acquire rights over what had become beach rather than land. In England the tidal area is normally Crown property, I'd guess it would normally be State property in the US, but if the landowner had purchased the beach too, they'd have those rights on what had been their land and was now their beach.

[Rascal Dog]

In England the tidal area is normally Crown property, I'd guess it would normally be State property in the US, but if the landowner had purchased the beach too, they'd have those rights on what had been their land and was now their beach.

In the USA, every State is different. In most, land below high tide is public. In others, land below low tide is public (Maine for one). In others, the dry sand up to the vegetation line is public (Oregon for one).

You can't buy a beach in Oregon. You can in Maine.

[shmengie]

Hard to fathom what this looks like in real life.
Google's historical views of Earth, makes it a little easier.
GIF'd it to make it a little bit easier still.

-enjoy, and/or just live w/it.

Oh, if you pay attention, you see #16 moves before it vanishes.

[kassy]

Like it´s running away but people moved it but not far enough.

[Downpuppy]

Maine used to be part of Massachusetts, & Mass. also follows the ownership to low tide rule. If you embiggen the map, you see lots of properties that are simply underwater. Once they lose their house, most people just want to be free of the leftover problems, and donate it to whatever land trust will take it.
Interesting that they moved the house knowing it only bought them a couple of years