Sea Level Rise, Acceleration, and Closure

Guest essay by Rud Istvan

Background

There is no doubt that interglacials change sea level (SL). And that sea level rise (SLR) can be dramatic on millennial interglacial time scales. That’s what happens when the vast Laurentide ice sheet (among others) melts. But sea level has changed relatively little in the past 7 millennia. We know from archeology that it rose somewhat in the Medieval Warm Period, dropped some during the Little Ice Age, and has been rising slowly since based on tide gauge records. This mostly natural variation is, from 1950-2000, about +1.8mm/year to 2.2mm/year (discrepancy explanation and references follow below). That rate is no cause for alarm. We coped with it for the past century, and can cope with it for the next.

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The anthropogenic global warming (AGW) question is whether SLR will accelerate into catastrophic AGW (CAGW) requiring urgent mitigation? Warmunists argue yes, with many alarming images such as National Geographic’s photoshopped Statue of Liberty half submerged (which would require that all of Greenland and Antarctica melts before the next glaciation sets in). We know that in the last interglacial, the Eemian, the sea level highstand was about 6.6 meters above present sea level, so the ice sheets did melt more with global temperature about 2C higher (perhaps 8C higher in Greenland). This took about 3000 years to achieve. That is (660cm/30 centuries) ~22 cm/century, or roughly 2.2mm/year. That rate is no different than the best estimate of present ‘true’ SLR found in what follows.

Consensus Belief

There are two parts to the SLR alarm meme. 1. SLR is accelerating because of AGW. 2. SLR will therefore become a big problem even if not one today. Ergo, future CAGW requires urgent mitigation. Hansen says up to 1 meter SLR by 2060 (and maybe more with tipping), so goodbye Miami Beach. The Obama administration uses occasional recent high tide flooding there to support his climate urgency– without revealing that Miami Beach is 2/3 fill dredged from Biscayne Bay, and is subsiding as the fill compacts and as the underlying Biscayne Aquifer subsides as it is drained to provide Miami’s fresh water.

There are many graphics floating about that support the SLR acceleration alarm.

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This seemingly authoritative graphic has been constructed out of two deceptions.

(1) Uses tide gauge records uncorrected for land motion. (C&W 2005 is actually doubly misrepresented: C &W data before 1950 is W,C,&G GRL 2006 [C&W 2005 is only 1950-2000], and there is no 1925-1992 reference period in the 2006 paper). C&W 2005 SLR 1950-2000 was 1.8 mm/year rather than 1.9 and was not accelerating. C&W used approximately 350 long record tide gauges for their ‘accelerating’ reconstruction. There are only 146 PSMSL tide gauges (TGs) within 1000 meters of a differential GPS to correct for vertical land motion of whatever cause, and only about 70 of those are long record TGs. So vertical land motion is NOT excluded in either C&W paper.

(2) Splice on satellite measurements since 1993 that fail the closure test below: observed SLR should roughly equal the sum of observed sea level contributions from thermosteric rise (OHC causes the estimated water column to expand as it warms) plus ocean mass increase (water volume from ice sheet losses).

Side comment: in the SLR literature, there are also two lesser possible SLR contributors: mountain glaciers, and groundwater extraction. Both are sufficiently uncertain and small that they are ignored in this post. There is little doubt that glaciers have been receding most places since 1900, for example in the Himalayas. But IPCC AR4 issued a retraction concerning its alarming conclusion that they would disappear by 2030. Most terrestrial groundwater is annually replenished; else water tables would fall and wells fail. That which is not replenished (e.g. the world’s largest aquifer, the Ogallala) is de minimus in the context of global SLR. (Ice density at 0C is 0.9187, water is 0.9998, so if 365 Gt ice (roughly 365 cubic km) equals 1mm of SLR [reference below] then 1mm of SLR requires adding about 335 cubic kilometers of water. Ogallala withdrawals are about 26-30 cubic km/year and in some places will be exhausted by 2030.)

Tide Gauge SLR

The actual rate of sea level rise is uncertain, let alone possibly detectable AGW acceleration. There are two basic uncertainties.

(1) SLR is inconstant because of multiannual changes in lunar tides (~18 year periodicy) and ocean currents/oscillations (~30-60 year periodicy). Tide gauges show this natural decadal variability almost everywhere. So fluctuations over just a decade or so should be discounted.

(2) SLR is locational because of geographic inhomogeneity. Land does not stand still thanks to plate tectonics, glacial isostatic adjustment (GIA), ground resource extraction (Miami water), and river delta sediment compaction (as in Bangkok). The NH is much better represented than the SH. One paper even said NH SLR is 2.0mm/yr, while SH SLR is only 1.1mm/yr. This peer-reviewed paper would be logically implausible to any 2 year old familiar with bathtubs and water.

SLR fluctuating and land not standing still are both illustrated by Juneau Alaska:

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So, what is the ‘true’ tide gauge (TG) measured SLR? There are three ways to estimate this: some big average of a lot of TGs hoping land motions cancel out (the Church and White example above, ~1.8mm/year 1950-2000), model GIA corrected TGs, and direct measurement differential GPS corrected TGs.

There have been a number of papers that have used various subsets and time frames of the ‘stationary’ (GIA or dGPS corrected PSMSL) TGs to infer more reliable estimates of SLR noted by the IPCC. Past half-century estimates range from about 1.7mm/year to about 2.0mm/year, with little to no acceleration. The most relevant recent estimate is Mörner, 2.2mm/year from 1970-2010 during the period when AGW was supposedly happening. This seems plausible, as the average dGPS TG SLR estimates for Western Europe (2.2), the US East Coast (2.1), Japan (2.3), and Australia (2.2) since 1950 are similar. Also proving the sea isn’t truly level, and dGPS isn’t completely accurate.

Satellite Altimetry

As the second chart above illustrated, satellite altimetry tells a very different story, and that story has ‘accelerated’ over time. The present NASA estimate from 1993 to the present is 3.4mm/year (with GIA +0.32). So is the estimate from University of Colorado (with GIA +0.31).

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In 2012 it was 3.1mm/year per the second chart above. In 2013 it was 3.2mm/year, as the following chart illustrates.

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The ‘acceleration’ arises from Jason-2. But the Jason-2 specification is for instrument stability not exceeding 1mm/year of drift.[1] The acceleration could just be instrument drift. Certainly there has been no causative change in global temperature; Jason-2 is flying during the infamous global warming ‘pause’. Perhaps a comparison to just launched Jason-3 can resolve this; there are already initial discrepancies between the two ‘birds’.

The most recent attempt to reconcile TGs to sat alt to ‘prove’ CAGW acceleration is Jevrejeva et. al.[2] The paper used 1277 PSMSL tide gauges (but explicitly without applying the customary inverted barometer correction—higher air pressure depresses sea level), used a modeled GIA land correction (which dGPS corrected GRACE Antarctic ice loss proved is very unreliable—the paper abstract even said, “Choice of GIA correction is critical…”), to find TG +3.1 versus sat alt +3.2 for the overlap period of 1993-2009 (the sat alt is wrong per both NASA and U. Colorado. Should have been 3.1 mm/year and an exact match, but that might have exposed the manipulated TG data deceits). It also purports to find SLR amplification at both poles, which illogically ignores the hemispheric bathtub problem noted above. It ignores the underlying closure problem entirely. It ignores known decadal tidal variability. The paper isn’t very credible; it seems a desperate warmunist [3] faux defense of the SLR acceleration belief.

Closure

The dGPS tide gauges do not agree with satellite altimetry by a factor of about (3.4/2.2) 1.5x. So which is more correct? SLR should roughly equal the sum of thermosteric rise and ice mass loss. Lets examine those components separately.

Thermosteric rise was estimated to be 1.23mm/year through 2003. Say 1.2. ARGO only estimates are slightly less, perhaps due to known greater uncertainties in the previous XBT sensors. The ARGO period 2005-2010 estimated thermosteric rise is 1.1mm/year (footnote 4).

Greenland’s ice loss depends on which decade, since the 1990’s lost less than the 2000’s. A PNAS estimate for 2003-2009 is 243Gt annually equaling 0.68mm/year. (The NASA conversion factor is 365Gt = 1mm, which would give 0.67.) Other published estimates for multiple years since 2000 range from 0.66 to 0.74. Say 0.7 for closure purposes.

Antarctica is controversial. Perhaps the best estimate is the new dGPS GIA correction to GRACE, which gives 135Gt/year, or 0.37mm/year. Say 0.4.

The sum is 1.2+0.7+0.4 = 2.3mm/year. If ARGO is used, the sum is exactly 2.2. Cazenave’s independently derived estimate from several other references in NCC (paywalled, caption to figure 3) is 2.2. All agree with the dGPS corrected SLR of ~2.2mm/year within uncertainties. There is closure without acceleration.

There is anything but closure with the satellite altimetry. NASA presently says on one web page that present thermosteric rise is 0.8 (wrong), mass gain is 1.8 (wrong), and that SLR is 3.4 (wrong). NASA apparently does not realize that 0.8 + 1.8 = 2.6 ≠ 3.4. NASA climate stuff is seemingly off in a lot of things–temperatures, SLR, ARGO, Antarctic ice loss, closure arithmetic…

There have been three attempts to reconcile satellite SLR to closure and TGs. One set of three similar papers cherry pick short time frames when satellite SLR was less (2.4, 2.5, 2.4 respectively), and throws in higher Antarctic ice loss contributions. [4], [5], [6] The second argues that satellite altimetry signal processing is wrong (Topex in particular) so the satellite era is really only 2.6mm/year (but accelerating with Jason-2) with closure achieved using higher Antarctic ice loss. The third argues that NASA’s +0.3 GIA is modeled wrong, and according to Peltier’s ICE-5g(VM2) GIA model it should really be -1 with corrected SLR (3.4 -0.3 – 1) 2.1mm/year and closure.[7]

None of these attempts seem very credible.

Conclusions

Tide gauges cannot be relied on for short periods like a decade, or without vertical land motion corrections. Correctly used, they presently estimate about 2.2mm/year with any evidence for acceleration within the uncertainty. That estimate closes with thermosteric rise and ice mass loss for ~2000-2010. The satellite altimetry SLR used to assert SLR acceleration is inconsistent with tide gauge estimates and with closure. SLR acceleration alarm is unjustified.


[1] OSTM/Jason-2 Products Handbook, JPL ref. OSTM-29-1237 (1/20/2009)

[2] Jevrejeva et. al., Trends and Acceleration in global and regional sea levels since 1807, Global and Planetary Change 113: 11-22 (2014)

[3] Warmunist is a term developed and footnoted in essay Climatastrophy in ebook Blowing Smoke. It is an homage to former Czech Republic President Vaclav Klaus’ 2007 book Blue Planet in green Chains, which compares to Lysenkoism.

[4] Chen et. al., Contributions…to recent sea level rise, Nature Geoscience 6: 549-552 (2013).

[5] Li et. al., Assessing the global averaged sea level budget from 2003-2010, Acta Oceanol. Sin. 32: 16-23 (2013)

[6] Willis et. al., Global Sea Level Rise, Oceanography 23: 26-35 (2010)

[7] Peltier, Closure of the budget of global sea level rise, Quaternary Science Reviews (2009), doi:10.1016/j.quascirev.2009.04.004

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firetoice2014

Satellites orbiting at 1336 kilometers above the earth measuring sea level to 0.1 mm precision suggests discrimination of 1 part in 23.76 billion, measuring a surface which is never at rest from a platform in constant motion. Impressive, if plausible.

They cannot. Read fn 1. A 2 meter average wave induces an error of ~2 cm, since the wave trough relects more brighty than the wave crest. The deeper you dive into Jason-2, the worse covered up uncertainty gets. Jason-2 spec is instrument drift of less than 1mm/ year. The entire variation in posted chart three could just be in spec instrument drift. See essay PseudoPrecision in ebook Blowing Smoke for a detailed explanation.

Greg

Since most of the signal comes from the trough of the swell you need to know the height of the swell to get the mean sea level. That is estimated from the noise profile of the data using a model. Tweak the model parameters to get the desired result.
As with most ‘climate data’ you can adjust it to fit your person preconceptions.

LdB

Given your argument how does the boring basic GPS system work to an accuracy of a couple of meters it shouldn’t work for exactly the same reasons you cited. I have no problems with people disputing what data means but arguing that calibrated data is wrong because you feel it’s wrong lacks a certain credibility.
LIGO measures to a precision of 1x10E-20 m and yet we have comments on here that doubt that as well but are too lazy to check the calibration work. So if you doubt the accuracy get off your butt and show the error in the calibration otherwise I might just doubt the accuracy of your comment.

simple-touriste

GPS can be checked on fixed targets.
I fail to see what is the analog of sea waves for GPS.
A kid’s intuition is that if you have a measurement made from the sky that disagrees with a measurement made on site, you bin the remote measurement. The kid is right, the climate sciensuivist is wrong, as usual.

LdB

Jason 2 data can be checked locally as well and generally is. Into your favorite search engine “comparison of local jason 2 data to tide gauges” and you can add the local area you want to look at. Most countries have run comparison of Jason data to their tide gauges.
So exactly the same as GPS and part of the calibration process.
The CRU even has a general comparison to all the tide gauges
http://sealevel.colorado.edu/content/monitoring-altimeter-drift-using-tide-gauges

Robert W Turner

LBD, if you fail to grasp that GPS locating a spot within a few meters and accurately measuring a constantly moving surface are not at all identical than it isn’t worth trying to explain.
It’s strange, also, that the tide gauge data and the satellite data differ by 1mm/yr. Maybe they should keep calibrating.
http://hockeyschtick.blogspot.com/2010/02/sea-levels-large-variances-between-tide.html

LdB

Actually Robert I understand perfectly, you actually got to my problem with the data in a round about way with an attempt at humour
Robert W Turner => “Maybe they should keep calibrating. ”
Bingo you got to the crux of the issue the data is continually calibrated it can’t go out which is how you get the accuracy and if it does they send up a new satellite. As per your article all the local site adjustments are already factored in which is why I was defying Ristvan to find one that was out because clearly he doesn’t know how the process works.
The uneasy question is not the accuracy of the measurement which is calibrated but what it is calibrated against and whether the measurement is valid in different periods which is exactly what your linked article is talking about.
In fact Jason 3 just went up and it takes months to get the data CALIBRATED and hence I can guarantee you that for the 95% of the earths surface covered it is within calibration and accuracy quoted.

Olaf Koenders

GPS reports Cartesian coordinates of X, Y and Z, but those coordinates originate from the computed centre of the Earth. It uses a mean sea level figure on the oceans, which is far less accurate to the millimetre. It’s easy to compute Z coordinates when they’re static, so ocean waves and atmospheric pressure changes will interfere and therefore accurate sea level can only be computed over time, not instant.

MarkW

You answer your own question.
GPS satellites are only a couple of hundred miles up, and their accuracy is to a meter or two, not 0.1mm.

MarkW

If your adjustments are orders of magnitude greater than the signal you claim to be seeing, then you aren’t doing science.

Robert H Smith

Corrections to Mark W’s comment…
The GPS satellites fly in medium Earth orbit (MEO) at an altitude of approximately 20,200 km (12,550 miles).
The Selective Availability feature was turned off in May 2000 which allowed civilian users access to the same accuracy as Military users. A new L5 signal has been added to the newer satellites being launched and the accuracy is improving quickly for civilian users. A 2015 report stated “average user range error (RMS URE) from 25 February – 3 March 2015 was 0.50 m for Legacy and 0.57 m for Modernized; best week for Modernized signals since the broadcast initiated April 2014 was 0.42 m for 6 – 13 January 2015”. It has been a few years since I worked on the system design, but my memory is that we were shooting for better than 0.3m (i.e. 30cm) when the L5 signal was available on most of the satellites. The accuracy of position or velocity determination is driven by a multitude of factors including movement of the GPS receiver, orbit knowledge accuracy of the satellites, signal interference sources, and update frequency of satellite position information.
To increase accuracy above the basic GPS satellites, NOAA’s National Ocean Service, manages a network of Continuously Operating Reference Stations (CORS) that provide Global Navigation Satellite System (GNSS) data consisting of carrier phase and code range measurements in support of three dimensional positioning, meteorology, space weather, and geophysical applications throughout the United States, its territories, and a few foreign countries. International GPS Service provides selected global improvements as well.
Finally, employing a large ground network of real-time reference receivers,… network architecture, and …real-time data processing software, the GDGPS System provides sub-decimeter (<10 cm) positioning accuracy and sub-nanosecond time transfer accuracy anywhere in the world, on the ground, in the air, and in space, independent of local infrastructure.
Bob Smith

LdB

Oh if you care to check the calibration of Jason 2 there are a number of papers on the subject just hit your favorite search engine with “Jason 2 calibration” and I am sure you will get the links to the papers. Then find the error you are sure must be there.

Basic gps has an accuracy of about 10 meters in 3d. Surely you know that. dGPS corrected by secondary known ground signals is much more accurate. More in 1D than in 2D than in 3D. That is basic knowledge known to all modern farmers.

LdB

That is domestic grade GPS but it is irrelevant the point is the number accuracy is calibrated it is given with +- error factors. It isn’t an estimate or an approximate answer.
So if you want to claim the number is wrong you are saying the error factor is not correct …. so prove it.

LdB, did so. Your counter is?

LdB

Your response doesn’t require a counter the Jason data is CALIBRATED your argument is nebulus something like pink aliens play with the Jason data when we aren’t looking.
Now I don’t agree with the interpretation of the data by climate science much as per the article above but it’s hard to fault the actual measurement. If you look at local site data and compare it to the Jason data for that area it’s pretty much the same … that is everything is within calibration.
You want to argue show me the calibration is out give me a reference even at a local site I can look at rather than pink aliens ate the data.

LdB

You know the gravity version of your pink aliens goes, you can’t prove to me gravity is within consistent formula everywhere on earth. You have to go and measure at every point on earth to do that.
Most of science just go tell you what lets just assume it’s all within the calibration and when you find the point on earth where it isn’t I will come and measure it.
No scientist is going to bother with your pink alien until you can find data that is out of calibration.

PA

http://sealevel.colorado.edu/files/current/j2-tg.png
Gee. the drift of Jason 1 was 0.1 mm/y.
The drift of Jason 2 is 1.1 mm/y
That would make our 3.4 mm/Y from Jason 3, 2.3 mm/Y in actuality.
Removing the GIA correction would get us down to 2.0 mm/Y.
So… the satellites aren’t that far off..

LdB

@PA July 21, 2016 at 10:52 pm
Yep the measurement has a drift .. weird hey 🙂
Now help some of the others out who clearly have never read how it works what does the drift actually represent.

Jeff Alberts

pink aliens play with the Jason data when we aren’t looking.

Now that’s just silly. Everyone knows the aliens are green.

Paul Mackey

Hear hear!

tomwys1

Here’s 13 (of what should have been 15) minutes of “Will the Real Sea-Level Please Rise” that tries to frame the issue: http://climateconferences.heartland.org/thomas-wysmuller-iccc9/

firetoice2014

Thanks for the link.

Walter Sobchak

Sea level rise is the most over hyped “catastrophe” of all of the AGW catastrophes.
First, men have legs and they can walk away from the rising tide toward higher ground. It may be objected that there are some very poor low lying countries like Bangladesh, but the fact is that their problems are overpopulation, ignorance, and bad government. Anything that happens to them kills myriads of people. Shutting down industry in the developed world in hopes of saving lives in Bangladesh is mere foolishness.
Second, men have hands, they ca construct sea walls, install pumps, and do many other things to deal with rising sea levels. Much of the Netherlands is below sea level, not because of rising seas, but because they reclaimed the bottom of the North Sea to farm and live on. The technology exists.
Miami Beach, and Manhattan, we will build walls and install pumps.South Carolina, we will move to higher ground.

Gary McCollom

Thank you.

Dirk Pitt

No, they make it sound as if some giant tsunami will drown millions of unsuspecting people in the middle of the night, while asleep.

philincalifornia

…. it’s the nouveau hobgoblin under the bed, or the monster in the closet.comment image

John Harmsworth

-Walter
I’m afraid I must disagree with you. While SLR clearly has a special place in the massive display case of lousy climate pseudo-science, I believe “ocean acidification” takes the blue ribbon for complete and utter b.s. Others may have their own choice as there are many to choose from.

philincalifornia

I think carbon dioxide ganging up over the El Nino Pacific regions and putting heat into the oceans specifically there takes some beating. If this ever gets to be a real award, we really should add up how many laws of physics have been broken before declaring a winner.

Seth

Shutting down industry in the developed world in hopes of saving lives in Bangladesh is mere foolishness.

If you could save a life, but it would cost money from your pocket, how much money would it have to be before you would refuse to save a life?

Walter Sobchak

“If you could save a life, but it would cost money from your pocket, how much money would it have to be before you would refuse to save a life?”
A lot, I give more money to charity every year than you earn.
However, the thesis of the Warmunists is so far out of touch with reality that it has no life saving potential at all. Indeed it would cause more damage than it could possibly save.
The problems of Bangladesh and the rest of the third world are not caused by the productive activities of other nations. They are caused by overpopulation, ignorance, and bad government. The climate has flat f***ing nothing to do with it.

MarkW

Making people poorer kills people as well.
So in reality you are asking how many people are you willing to kill in order to save one life.

Jeff Alberts

Bangladesh seems to have problems whether it’s warm or cold. Remember the charity concerts in the 70s for them?

Brian H

B-desh is a delta = continuous silt deposits and variance, to which the locals are thoroughly adapted, and on which they depend. Fake issue.

indefatigablefrog

Exactly – not only is the actual observed rise non-spectacular and non-accelerating and low by multi-millennial standards – BUT – we are under no obligation to stand on the shoreline at high tide for three hundred years waiting for the average height of the surge to begin to wet our underpants.
As I once read in a paper published by GWPF – ” they seem to have overlooked the consideration that people are not potted plants”.

Jeff Alberts

As I once read in a paper published by GWPF – ” they seem to have overlooked the consideration that people are not potted plants”.

The green ones are.

EricHa

Here is a report from the alarmist BBC on the Bangladesh delta.
https://www.youtube.com/watch?v=izHmK578rzE 5:17
Ignore the garbage about climate change and increased erosion spouted by the presenter. I post this as it is the best view of what is happening there I have seen on the tv. As land is eroded in one place more is created elsewhere. It is a delta and has been doing this since the Indian sub continent ploughed into the Asian continent.
People live here because the land is fertile for crops the same as the slopes of a volcano. There is no ignorance or bad government, people farm this land because it is productive and the fact that it is being eroded is just an occupational hazard. Trying to stop the delta doing what a delta does is like trying to stop the tides.

EricHa

They won’t know what to worry about first
http://i.dailymail.co.uk/i/pix/2016/07/22/14/3680DDD600000578-0-image-a-102_1469193266624.jpg
Giant ‘megathrust’ fault is discovered in the Earth’s crust under the most densely populated part of the globe that could wipe out ‘tens of millions’ in an earthquake
http://www.dailymail.co.uk/news/article-3703378/Giant-megathrust-fault-discovered-Earth-s-crust-densely-populated-globe-wipe-tens-millions-earthquake.html

essentially the continuation of th Andaman thrust that caused the Sumatra mega-tsunami.

woobble

I agree that man can walk away, but for Miami pumps aren’t really going to work. The bedrock is porous limestone and highly permeable and so floods will find a way through no matter what you do. If you’ve ever tried to sandbag a house built on a concrete slab during a flood you will instantly recognise the problem, the flood comes through the floor.

Bartemis

Very impressive, Rud.

Michael Jankowski

“…Ogallala withdrawals are about 26-30 cubic km/year and in some places will be exhausted by 2030…”
Guess what will get blamed for that? Climate change, of course!

The first problem is that there is no such thing as sea level. Wave, chop, tides, foam, spray, etc are so great, that the instrument measuring this must dampen these effects to get any usable readout. This introduces bias at the instrument, and is specific to each instrument. Every tide gauge has its own unique bias. Just calling them gauges and throwing them together for a lump of data is not producing meaningful results. A specific, internationally agreed upon, standard of what sea level is, and a standard measurement system have to be devised. Since this has not occurred, I would claim the data means nothing.

Per comment, even the J-2 documentation acknowledges the wave problem that troughs reflect more than peaks.

expat

The difference in sea levels of the north and south ends of the Panama canal are something like 2 meters. I never could understand the term sea level measured to anything less than a few centimeters.

Menicholas

“The difference in sea levels of the north and south ends of the Panama canal are something like 2 meters.”
Assuming this is true, and I have no reason to doubt it, this could be a decent source of hydroelectric power.
All we need is a set of very large, cheap, and relatively friction-free pipes connected the two sides.
Admittedly a tall order.
But perhaps something to think about.

Menicholas
Lauren R.

Here’s a simpler view of the difference in measurements between satellites and tide gauges. If you look at NASA’s “Vital Signs” website, there are two graphs of sea level.
http://climate.nasa.gov/vital-signs/sea-level/
The top graph is satellite (3.4 mm/yr) and the bottom one is tide gauge (conveniently, with no rate listed but it works out to about 1.5 mm/yr or less than half the satellite value). They overlap for 17 years between 1993 and 2000. Notice there is no change in the trend line in either graph during that 17 year period; in other words, no acceleration of sea level rise. And after 2000, the satellite graph shows essentially no (or negligible) acceleration in sea level rise. But they report different trends (3.4 mm/yr vs 1.5 mm/yr).
Nowhere on either graph is there an acceleration of sea level rise from 1.5 mm/yr to 3.4 mm/yr. They are simply reporting different numbers for the same trend, which means there is a discrepancy that needs to be explained. Either the satellite data is wrong or the tide gauge data is wrong or they’re both wrong, but nowhere is there any dramatic acceleration of sea level rise as widely claimed.

Lauren R.

Sorry…7 year overlap, not 17 year overlap.

Walter Sobchak

“Either the satellite data is wrong or the tide gauge data is wrong or they’re both wrong”
Or they are both meaningless measures of junk.

LdB

They have meaning to what they are referring. The tide gauges and the panama canal measurement above are LOCAL measurements. The satellite measurement is covering the whole of the oceans which is a very different thing. If you want to compare the tide gauges to the satellite data you need to add all the tide gauges together around the world and you probably don’t have enough and average them out.
Whether it is more appropriate to use local data measurement or use the global measurement depends on the question you are asking.
Lets turn this to you telling me how far to the shop. You could give me a global measurement and tell me it is 2000KM from London but only 1400km from New York. You could give me the local answer that is 3km from where I am currently standing. There would not be anything wrong with either answer just which one is easier to deal with depends on the question.
It isn’t rocket science and measurements are measurements they are just data ….. meaning requires interpretation which requires a human or at least something with an intellect.

Greg

It isn’t rocket science and measurements are measurements they are just data …..

You clearly do not know as much as you think you know about satellite measurement of sea level.
They are not just “data” there are a bunch of “corrections” which are applied to produce the “data”. These rely on models of the signal path, ocean roughness and bunch of other stuff. In essense, like most climate “data” you can get pretty much the answer which best fits your personal bias by choice of the multiple model parameters.
There is then the post measurement adjustments like “inverse barometer ” correction. This gets applied to whether you want it or not even to global where it makes no sense. A storm or depression may locally raise mean sea level but it cannot such the whole worlds ocean higher. Colorado no longer present both sets of data, you get global MSL with IB whether it makes sense or not.
Then there’s GAIA [sic] correction. Where they arrive at a GMSL floating, phantom like above the waves, due to *supposed* changes in the ocean basins. That is not data because no one has measured the changes in the ocean floor that are being assumed. Is it supposition not “data”.
Like you say it depends upon what the question is. The alarm about sea level rise is all the talk of flooding. For that GAIA adjustment is irrelevant. All you need is local tide gauge measurements. REAL sea level.

The biggest frig factor is that satellites are basically measuring the trough of the swell, which can be several metres in open ocean. To get the mean sea level you need to know the height of the swell. This is estimatedfrom the noise in the measurements.

That is one huge guestimation which can be tuned to give whatever you’d like as the result.
In view of the highly politicised stance at U. Colorado, they are the last people I would trust to be making an honest, objective guess.
They force feed us GAIA adjusted data because they say they want it be a metric of AGW but they still call it “sea level” when it floats above the waves. The no longer provide the data without inv. barmometer “correction” so it can be assessed. Total lack of transparency. Political activism , not science.

Ray Boorman

You are correct, LdB. Tide gauge measurements, like temperature measurements, are useful for local information, nothing more. To use either of them for the purpose of estimating small variations in the artificial constructs called “global average temperature” or “average sea level” is a falsehood which is only useful for people with a political axe to grind.

Jeff Alberts

You are correct, LdB. Tide gauge measurements, like temperature measurements, are useful for local information, nothing more. To use either of them for the purpose of estimating small variations in the artificial constructs called “global average temperature” or “average sea level” is a falsehood which is only useful for people with a political axe to grind.

+as many as possible

PA

https://jason-3.cnes.fr/en/JASON3/GP_science.htm
“Global sea level is the average height from all of the Earth’s oceans from the sea floor”.
https://www.sciencedaily.com/terms/sea_level.htm
“Mean sea level (MSL) is the average (mean) height of the sea, with reference to a suitable reference surface.”
http://www.tidesandcurrents.noaa.gov/est/faq
The Intergovernmental Panel on Climate Change (IPCC) Report estimates that the global sea level rise was approximately 1.7-1.8 millimeters per year (mm/yr) over the past century (IPCC, 2007), based on tide station measurements around the world, with projected increased trends in sea level in the 20th Century based on global climate models.
1. Mean sea level is the average sea level relative to a suitable reference surface.
2. The masking of land and the addition of an estimated 0.3 mm/Y (for GIA) to the satellite computed GMSL indicates the satellites are computing the change in average height from the estimated location of the ocean floor.
3. The GMSL from tidal gauges can be:
a. The tidal gauge sea level rise.
b. The tidal gauge sea level rise corrected for isostatic change via GPS.
c. The tidal gauge sea level corrected for local subsidence.
d. The tidal gauge sea level rise corrected for isostatic change via GPS and corrected for local subsidence.
4. It seems obvious that tidal gauges at a minimum have to be corrected for local subsidence. Otherwise tidal gauges from locations like New Orleans that are sinking 8 mm/Y are worthless.
5. The 0.3 mm/y GIA satellite correction implies that land is rising 0.7-0.8 mm/Y relative to a computed geoid.and 1.0 – 1.1 mm/Y relative to the ocean surface.
6. Topaz/Jason series satellites only measure sea level from 66° N to 66° S.
From this you can explain all the numbers. Satellites are measuring estimated ocean depth over most of the earth, except for the Arctic ocean. Tidal gauges are measuring some variation of ocean relative to a land position.
I suspect when the earth is slowing (20th Century) satellites read low. When the earth is speeding up (21st century) satellites read high since the Arctic level is dependent on LOD change and the satellites don’t measure the Arctic Ocean.
Mean sea level measurements that are different are generally measuring different things. People who claim the satellites are measuring sea level as conventionally understood are factually incorrect. They are measuring estimated change in ocean depth from 66° N to 66° S.

Xyzzy11

PA, re IPCC report, I think we’ve already had the 20th century (ended December 31, 1999). I suspect 21st century is meant

PA

You might be correct. I’m not their writer or editor so I can’t claim any insight into what they meant to write.

Lenny

I like reading science like this, where the hypothesis is assessed against closure constraints to check if it seems about right. Nice work.

Bill Illis

I note that Church and White has access to the complete PMSL tide gauge database but they only used about half of the records available. It was still a big number but when data selection of any kind is used in this “science”, obviously a bias is introduced. Any number can be manufactured with any kind of data selection of the tide gauge data.
Secondly, the satellites cannot possibly measure with an any accuracy at all. From 1400 km orbits, all the raw data has to be reprocessed with a dozen algorithms before it provides any kind of useful information and, again, a bias is introduced.
For example, from orbit, sea level is 42 kms higher at the equator than at the poles. Yes, you read that right; 42 kms. They get 3.2 mms/year after measuring a difference which is 13 million times greater than that in just the equator to the poles differential??? That is only one of about 20 things that have to be algorithmized. Bias anyone.

@ Bill Illis, Did they add in the lunar tidal bulge ?

Ray Boorman

Naah, couldn’t possibly be any or bias, let alone errors, in their “measurements”, Bill! These guys have intellects greater than any old god you care to name, so they must be right.

philincalifornia

Donald Kaspar
“A specific, internationally agreed upon, standard of what sea level is ……”
Seriously, with respect, you think that hiring 10,000+ people, overseen by Lysenkoists, who can’t get real jobs to come up “internationally” with what sea level actually is is a good idea ??

Seth

That rate is no cause for alarm.

I think that depends where you live.
Sydney’s northern beaches had a low pressure system and storm swell on a tide that was only about 1 cm below the highest tide of the year. The result were higher waters than ever before … only by a centimeter or so, but that took 50 metres of beach in places.
Erosion like that has been less well documented, but of greater social significance in Bangladesh.
Similarly, in the US, the Federal Flood Insurance program is about $24 billion in debt. Whether or not the taxpayer comes to the rescue, premiums will have to increase.

The anthropogenic global warming (AGW) question is whether SLR will accelerate into catastrophic AGW (CAGW) requiring urgent mitigation?

I think that the question is “Is the expected cost of reducing greenhouse emissions lower than the cost of dealing with the impacts”?
Neither is there any “urgent mitigation” technology available that can replace an ice sheet and get rid of the enthalpy of fusion to space.

Michael Smith

Seth, I know the northern beaches from visiting family there and have holidayed right on the beach at Long Reef so have considerable sympathy for the affected residents. But this was not an isolated event; identical storms have occurred several times in the last century including 1925, 1945 and 1967. There is no evidence to blame humanity for the damage done other than for local governments who refuse to do their duty to ratepayers.

You bring up a good point Seth. Erosion is never factored in when “sea levels” are calibrated. Hence high wave action that takes sand from beaches gets to be misconstrued as sea level rise. The fact is, regional councils no longer maintain seawalls as they used to. They wait until they crumble now and call it climate change. Then money can be saved reducing maintenance and made from updating eco penalties and resource consents as a tax for living close to the waves. The less spending by councillors, the higher they can set their own incomes.

Ray Boorman

Seth, even an unedumacated dolt like me knows that the erosion of the beaches in Sydney was caused by water moving towards the land in the form of 5 – 8 metre waves, with 40 knot winds pushing them. One centimetre of water, or one metre even, if it is just idling along on a normal tide, could not cause anything like the erosion seen.

Robert from oz

Sydney had an east coast low at the same time they have the highest tide of the year , east coast lows have nothing to do with AGW .

pbweather

The result were higher waters than ever before

Anything data or links to back this up?
This from the NSW Govt

Professor Turner said Collaroy and Narrabeen beaches had been surveyed for the past 40 years, and were among only “half a dozen sites anywhere in the world where we have a several-decade record of how a beach has changed and varied through time”.
He said the beach width had varied by up to 80 metres in the past 40 years, but generally the “sand comes back”.

Note that this event removed 50m of sand but it has removed up to 80m in the past 40 years.
Low air pressure results in roughly 1cm rise in sea level per 1mb of pressure below the standard atmosphere pressure which is 1013mb. The low that caused this storm was probably around 990mb which means that you had a perfect storm of near highest spring tides, large swell and and extra 20-25cm of low pressure induced sea level rise and probably a storm surge as well to some extent.
A freak storm in my home town in WA brought massive swells resulting in 100 plus year old Norfolk Island Pine trees to be wash away and fall down on the town beach. This occurred in the late 1980s. This is not climate change. It is a freak event when all the factors that can cause coastal erosion did so in one event. This applies to any extreme storm anywhere in the world. Those pines have been replanted and the beach is back to where it was now.
To say this is due to sea level rise from AGW is just nonsense and cherry picking.

Menicholas

Sand that is removed from beaches during winter storms is rarely gone forever. It is just offshore. What has mainly occurred is a redistribution of the shape of the sandy bottom.
Gentle waves in summer tend to move sand onshore, storms during winter tend to move it offshore.
High school physical geography.

bw

“The sum of steric sea level rise and the ocean mass component has a trend of 1.1 ± 0.8 mm per year over the period when the Paulson GIA mass correction is applied, well overlapping total sea level rise observed by Jason-1 and Jason-2 (1.3 ± 0.9 mm/a) within a 95% confidence interval.”
From this NOAA sea level analysis of all available data
http://ibis.grdl.noaa.gov/SAT/SeaLevelRise/documents/NOAA_NESDIS_Sea_Level_Rise_Budget_Report_2012.pdf
The NOAA paper is summarized here
http://hockeyschtick.blogspot.com/2012/12/noaa-2012-report-finds-sea-levels.html
Also note the extensive analysis of the Tasmanian sea level bench mark which was established in 1841 and shows a very small sea level rise since then.
http://www.john-daly.com/index.htm

Rud,
Much appreciated. I have also used estimates of SLR from the LGM to the onset of the Holocene to demonstrate that doom and gloom estimates of AGW pale in comparison to what nature actually typically achieves. However, discussion of glacial terminations, or even issues associated with our present measurement efforts may not be as well-focused as discussions relative to the end extreme interglacials.
Based on my research, the Holocene is presently 11,719 years old (+/-99years). Only one post Mid Pleistocene Transition (MPT) appears to have lasted longer than about half a precession cycle, which varies between 19-23kyrs and with us being at the 23kyr point now, making 11,500 half. Technically, this should shift the focus on SLR towards what has actually transpired at the end extreme interglacials, which include MIS-11 and MIS-5e, while provisionally allowing for MIS-19, MIS-9 and MIS-7, as they too may have achieved sea levels close to, equal to or greater than MIS-1 (the Holocene).
Rationally, this should shift the focus of climate change discussion towards how to disentangle AGW effects from the much more dramatic natural effects that attend glacial inception. Because glacial inception is what takes place when interglacials go kaput:
“We will illustrate our case with reference to a debate currently taking place in the circle of Quaternary climate scientists. The climate history of the past few million years is characterised by repeated transitions between `cold’ (glacial) and `warm’ (interglacial) climates. The first modern men were hunting mammoth during the last glacial era. This era culminated around 20,000 years ago [3] and then declined rapidly. By 9,000 years ago climate was close to the modern one. The current interglacial, called the Holocene, should now be coming to an end, when compared to previous interglacials, yet clearly it is not. The debate is about when to expect the next glacial inception, setting aside human activities, which may well have perturbed natural cycles.”
Crucifix, M. and J. Rougier, 2009, “On the use of simple dynamical systems for climate predictions: A Bayesian prediction of the next glacial inception”, Published in Eur. Phys. J. Spec. Topics, 174, 11-31 (2009)
http://arxiv.org/pdf/0906.3625.pdf
Direct evidence for sea level fluctuations lower than present are probably still submerged. What we find for those that exceeded the Holocene’s are that (a) the end extreme interglacials typically were visited with from 2 to 3 strong positive thermal pulses right at their very ends (3 for MIS-19 and -11, 2 for MIS-5e), with (b) numerous lesser pulses and fallbacks attending each. Virtually all of the lesser steps exceed the IPCC’s worst case estimates (AR4 and AR5), while the major pulses exceed them by nearly 2 orders of magnitude.
And what do the end extreme interglacials tell us?
“Rapid changes in sea level and associated destabilization of climate at the turbulent close of the last interglacial maximum appear to be recorded directly in the geomorphology, stratigraphy, and sedimentary structures of carbonate platform islands in the Bahamas. Considered together, the observations presented here suggest a rapid rise, short crest, and rapid fall of sea level at the close of 5e.
“The lesson from the last interglacial “greenhouse” in the Bahamas is that the closing of that interval brought sea-level changes that were rapid and extreme. This has prompted the remark that between the greenhouse and the icehouse lies a climatic “madhouse”!
conclude Neuman and Hearty (1996) https://www.researchgate.net/profile/Paul_Hearty/publication/249518169_Neumann_A_C_Hearty_P_J_Rapid_sea-level_changes_at_the_close_of_the_last_interglacial_substage_5e_recorded_in_Bahamian_island_geology_Geology_24_775-778/links/0c96051c6e66749912000000.pdf
“Sea level was 6-7 m higher than present during the last interglacial highstand 125,000-115,000 years before present (MIS 5e). Evidence from New Providence Platform, Bahamas, indicates that it was not a single rise and fall but instead oscillated a minimum of 12 m over a few thousand years.”
“Beach deposits that are +7.6 m above present sea level on New Providence Island represent the older peak of MIS 5e sea level. A down-stepping beach ridge indicates a subsequent sea-level position at +7.0 m. A calcrete in the subtidal deposits adjacent to the beach documents the mid-MIS 5e sea level drop. In the Exumas, a calcrete associated with this fall separates subtidal facies at -5.2 m. Sea level rises again to form the younger MIS 5e highstand; this rise is represented by a beach ridge at +5.1 m on New Providence Island and Exumas reefs up to +1.5 m above modern sea level. Parallel down-stepping beach to eolian dune transitions provide evidence for a pulsed down-stepping of sea level at the end of MIS 5e. The lowest occurrence of this transition is approximately -12 m below present sea level.”
“These highstand oscillations recorded in the Bahamas and elsewhere require another, yet unexplained, forcing mechanism of much shorter duration than Milankovitch frequencies but also document rapid climate changes during warm interglacial periods.”
https://gsa.confex.com/gsa/2012AM/finalprogram/abstract_212012.htm
I am stopping at three links to avoid automatic moderation. My current quotation/citation compilation runs to 90 pages.
What this should inform a sentient entity is that it is ludicrous to even be mildly concerned about a few feet of SLR. What we should be expecting is the onset of glacial inception, and the climatic madhouse that it is. Minimum estimates for the SLR that attended the second and final thermal pulse at the end-Eemian is about +6.0 meters. “”Business as usual” (worst case) AR4 estimates for SLR is about +0.6 meters, +0.8 meters for AR5.
Why should concern about AGW be taken even mildly? Actually, they should not be. And why is that? Well, we instantly run into the gob-smackingly simple construct known as signal to noise ratio (SNR). If our AGW “signal” is a whopping +0.6 to +0.8 meters then rationally we should just forget all about it. Homo sapiens has yet to devise a means of detecting a “signal” that is, at best, 10% of the normal natural background envelope. In this case at least +6.0 meters.
How will H. sapiens be able to accurately assign 1 of the 10 +0.6 meter SLRs to ourselves, if sea level, yet again, runs up +6.0 meters anyway? Oh yeah, the 3rd +0.6 meter rise is ours. Right………got it! From a rational perspective, this should end the entire debate. Even if we had the accurate instrumentation to reliably detect a signal an order of magnitude less than the background noise envelope, this does almost nothing with respect to the 1st 800lb gorilla in the climate change room with us. Glacial inception: the climatic madhouse.
Rationally, the ends of the previous extreme interglacials is where the forefront of the debate should be focused. Focusing on terminations is useful in that it can constrain speed and magnitude of SLR, but not so relevant when considering what occurs at the end interglacials.
But what about that 2nd 800lb gorilla? What if the climatists are dead right about CO2/AGW? Would they then not also be correct as to what to do about CO2/AGW? Let’s follow that one to its logical conclusion. Go ahead, strip the CO2 etc. climate security blanket out of the late Holocene atmosphere? Would this not be the only presently known speedbump to the tipping-point known as glacial inception? Wouldn’t that aid and abet glacial inception?
As it turns out, if the climatists are right about CO2/AGW (a big if), then they would be dead wrong to do anything but “business as usual” about it.
Rud, if I may suggest, you may find these two avenues well worthy of pursuit.
Personally I find the entire climate change/global warming debate to be the most definitive intelligence test ever devised. If one isn’t even aware of when we all live (the now half-precession cycle old Holocene….), then all other discussions become pretty much nothing but a silly buggers game.
One of the more stinging insults I remember was leveled at the UNIX community back in the early 1980’s:
“When a mathematician sits down to solve a math problem with a pencil, which should he/she be more concerned with? The math problem? Or the pencil?”
Fit to the climate change debate: “When a climatist is squealing down the climate change tracks, which should he/she be more concerned with? The wasp (IPCC et al) buzzing around his/her head? Or the Milankovitch climate freight train bearing down on them?”

Toneb

“Or the Milankovitch climate freight train bearing down on them?”
Certainly not that my friend as it’s 10’s thousands of years in the arrival.
Denizens on here aren’t worried about events that may occur later this century and next that conceivably will affect their future offspring (you don’t?). So in that context that statement is bizarre.

“Certainly not that my friend as it’s 10’s thousands of years in the arrival.”
Toneb, not so slow there my friend!
“According to the marine records, the Eemian interglacial ended with a rapid cooling event about 110 000 years ago (e.g., Imbrie et al., 1984; Frenzel and Bludau, 1987; Martinson et al., 1987), which also shows up in ice cores and pollen records from across Eurasia. Adkins et al. (1997) suggested that the final cooling event took less than 400 years, and it might have been much more rapid.” http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.540.101&rep=rep1&type=pdf
“MIS-5e ended abruptly with a rapid transition to glacial conditions, the lake was covered by a layer of firnified snow and ice, and phototrophic biological activity ceased for a period of c. 90,000 years.”
“The transition from interglacial into glacial conditions was rapid and is represented in its entirety between 26 and 23 cm. This suggests that the end of MIS5e was a relatively sudden event and not a gradual transition to colder conditions.”
“The transition into glacial conditions was a relatively sudden event. This is supported by marine and ice core records.” https://www.researchgate.net/profile/Elie_Verleyen/publication/222333370_Interglacial_environments_of_coastal_east_Antarctica_Comparison_of_MIS_1_%28Holocene%29_and_MIS_5e_%28Last_Interglacial%29_lake-sediment_records/links/0c960525ff43b0ac6b000000.pdf
“Finally, the very abrupt end of the LI, that occurred within no more than 0.15 ka (Fig. 3b), but that lagged by ~6.3 ka the onset of long-term decreases in SST, Vostok dD and CH4 and increase in global ice volume, once again indicates a nonlinear response and suggests important threshold processes.” http://www.pnas.org/content/104/2/450.full?origin=publication_detail
(0.15ka=150 years)
“Investigating the processes that led to the end of the last interglacial period is relevant for understanding how our ongoing interglacial will end, which has been a matter of much debate…..”
“The onset of the LEAP occurred within less than two decades, demonstrating the existence of a sharp threshold, which must be near 416 Wm2, which is the 65oN July insolation for 118 kyr BP (ref. 9). This value is only slightly below today’s value of 428 Wm2. Insolation will remain at this level slightly above the inception for the next 4,000 years before it then increases again.” Sirocko et al (A late Eemian aridity pulse in central Europe during the last glacial inception, nature, vol. 436, 11 August 2005, doi:10.1038/nature03905, pp 833-836)
Of course, then there is the not so little problem that if most post-MPT interglacials lasted about half a precession cycle and the precession cycle varies between 19,000 and 23,000 years, than half of each allocates something like 9,500 to 11,500 for each of them.
So, I guess my question for you would be if all but one post-MPT interglacial lasted in the vicinity of say 10,000 to 12,000 years, then precisely how could the end of each take 10’s of thousands of years to arrive?
Are you, perhaps, using matheMANNics or ALGOREithms?

“Denizens on here aren’t worried about events that may occur later this century and next that conceivably will affect their future offspring (you don’t?). So in that context that statement is bizarre.”
Fascinating logic, I must say. So let me see if I got this straight. Folks are not concerned about events that may occur later this century or the next? That truly is bizarre, if that is what you meant. Basically, that is actually what all of this is about. And, generally speaking, I have come of the notion that there are basically three major classes of denizens, to use your word, that are concerned about AGW, parents, parrots and those enamored of flexible ethics. Parents, precisely because they have offspring in the offing. Parrots, those capable of repeating things they do not understand. And the Al Gore’s, Mark Strong’s, Michael Mann”s etc. et al who just make stuff up to suit themselves.

Toneb

Nope, try reading again … The next glacial cycle is not due to arrive until ~50,000 year time according to the MC theory.
The premise of the OP was that we should prepare for it.
MC theory is for a slow descent into NH cooling.
Yet, denizens here dismiss any threat on the order of ~100 years from now as being unproven, or worse, falsified.
I just find it amusing my friend.
https://en.m.wikipedia.org/wiki/Milankovitch_cycles#
“The amount of solar radiation (insolation) in the Northern Hemisphere at 65° N seems to be related to occurrence of an ice age. Astronomical calculations show that 65° N summer insolation should increase gradually over the next 25,000 years.[24] A regime of eccentricity lower than the current value will last for about the next 100,000 years. Changes in northern hemisphere summer insolation will be dominated by changes in obliquity ε. No declines in 65° N summer insolation, sufficient to cause a glacial period, are expected in the next 50,000 years.”

Toneb, try to keep up. The 50kyr estimate comes from a 2-dimensional model of intermediate complexity hyped since the late 90’s. It was soon put to rest (2005) by development of the LR04 stack of 57 globally distributed deep sediment cores (observations):
“Recent research has focused on MIS 11 as a possible analog for the present interglacial [e.g., Loutre and Berger, 2003; EPICA community members, 2004] because both occur during times of low eccentricity. The LR04 age model establishes that MIS 11 spans two precession cycles, with 18O values below 3.6 o/oo for 20 kyr, from 398-418 ka. In comparison, stages 9 and 5 remained below 3.6 o/oo for 13 and 12 kyr, respectively, and the Holocene interglacial has lasted 11 kyr so far. In the LR04 age model, the average LSR of 29 sites is the same from 398-418 ka as from 250-650 ka; consequently, stage 11 is unlikely to be artificially stretched. However, the June 21 insolation minimum at 65N during MIS 11 is only 489 W/m2, much less pronounced than the present minimum of 474 W/m2. In addition, current insolation values are not predicted to return to the high values of late MIS 11 for another 65 kyr. We propose that this effectively precludes a ‘double precession-cycle’ interglacial [e.g., Raymo, 1997] in the Holocene without human influence.”
http://large.stanford.edu/publications/coal/references/docs/Lisiecki_Raymo_2005_Pal.pdf
Oh, and Wikipedia and climate? Have you also kept up with the Connolly imbroglio?

tty

Hearty is Warham of sea-level research. His papers should be taken with several grains of salt.

Clyde Spencer

Rud,
With respect to your comment about aquifers being recharged annually: Anecdotally, something that I have some first hand knowledge about, is that when the first settlers arrived in the Santa Clara Valley (CA), there were artesian wells in the east side of the valley. The drilled wells elsewhere were fairly shallow. I think it was around the 1920s that reservoirs were put in around the valley and the impounded Winter rains were used to feed percolation ponds. Despite the intervention to try to recharge the aquifer, by the 1970s, the wells supplying water locally were over 500 feet deep. The residents of the valley are now having their water supplemented with water from Hetch Hetchy and other reservoirs to the east. It is generally thought that major aquifers recharge slowly, over thousands of years, and rarely recharge as fast as they are drawn down with human use. This problem is compounded by the compaction of the sands and gravels, reducing the amount of water that the aquifers can hold.

Cannot disagree. My wells omm

Grey Lensman

simple, reverse drill for oil so to speak. drill and frack in a sensible engineered way
Problem solved

tty

You are talking about deep aquifers that are often recharged from distant mountains and sometimes actually consist of “fossil” water from a wetter past. They tend to get most attention, since they are often vital to arid areas (like California), but in most of the world ground water is just a few meters down and is re-charged annually.

Duster

Clyde, one of the biggest effects on reservoir recharging is plant cover and not necessarily in a positive way. Up through the middle of the 19th century indian burning in California limited the development of understory plants and also the rate at which overstory trees reproduced. Since every plant out there competes for ground water to avoid wilting, heavy vegetation actually draws water tables downward, and dense forests pull it even deeper. In Oregon in the 1990s hundreds of square miles of trees effective killed each other battling it out for ground water. Many old time ranchers I know have discussed the effects of unchecked growth and fire. They tell me that intense fires sometimes are followed renewed spring action in their pastures.
In the Hetch Hetchy region the number trees and density of forest growth along with understory and brush growth are far denser now than they were 120 years ago. There are good historic photos in Yosemite that reflect this change. It is also a fact that Gold Rush photos of many locations show far fewer trees and little or no brush. The common explanation is that the miners wiped out the vegetation. However historic diaries contradict this in many instances. California has not had much “natural” landscape for at least 2,000 years and probably longer. The actual cause of the aquifer problem is most likely the result of both excess pumping and fire suppression, combined with the slow percolation rates – and possibly pore aperture collapse as the pressure in the aquifer diminishes.

Good discussion. <2mm growing to claims of 2 meters, entirely normal for CAGW.

Michael Carter

“There is little doubt that glaciers have been receding most places since 1900, for example in the Himalayas”
Any decent research out there that studies the truly global situation? Glaciers have to be one of the most important indicators (imo). Surely someone has tried to put all the current data together?
Growth or decline: it does not matter we seek truth

Don Morton

Some Karakorum glaciers are advancing and possibly some Himalayan glaciers as well. The expansion or contraction of a glacier also depends on changing precipitation so shrinking glaciers are not direct evidence of global warming.

Javier

Glaciers have been globally declining since about 1850
http://i1039.photobucket.com/albums/a475/Knownuthing/rhoneglacier-series_zpsccodx9jy.png
The decline goes further than it should for the time in the Holocene we are. This indicates that modern global warming is not the typical Holocene warming. It does suggest increased CO2 is increasing glacier melting beyond Holocene trends.
http://i1039.photobucket.com/albums/a475/Knownuthing/Glacier%20extent_zps4smk8tz8.png
A) Koch & Clague 2006 meta-study of global glacier extent showing that current retreat exceeds the global range and minimum extent trend since mid-Holocene (Trend lines added). Notice how it shows glaciers now shorter than Medieval Warm Period and Roman Warm Period.
Koch, J., & Clague, J.J. 2006. Are insolation and sunspot activity the primary drivers of Holocene glacier fluctuations? PAGES News, Vol. 14 No 3 pp 20-21.
http://kochj.brandonu.ca/pages_2006.pdf

Bruce Cobb

Nice cherry-picking! When you want to show “unusual” glacier retreat, you definitely want to start during a time (the end of the LIA) when they had advanced some.

Javier

What cherry-picking? The one you are suggesting? That meta-study uses a great number of glaciers over the entire Holocene.
Just so you understand the unusual retreat. Why do you think Ötzi, that was buried 5200 years ago, became unburied just now? And Ötzi is not a special case. A lot of organic remains dated to the period 6000-4000 have become unburied over the last decades. Some examples from the bibliography:
1. J. Oerlemans. Holocene glacier fluctuations: is the current rate of retreat exceptional? Annals of Glaciology, Volume 31, Number 1, January 2000, pp. 39-44(6)
http://www.ingentaconnect.com/content/igsoc/agl/2000/00000031/00000001/art00008
“Integrations for a 10 000 year period, driven by random forcing of a realistic strength, show that the current retreat cannot be explained from natural variability in glacier length and must be due to external forcing.
2. Johannes Koch, John J Clague and Gerald Osborn: Alpine glaciers and permanent ice and snow patches in western Canada approach their smallest sizes since the mid-Holocene, consistent with global trends. The Holocene 2014 24: 1639
http://kochj.brandonu.ca/ho_2014.pdf
“Glacier retreat in western Canada and other regions is exposing subfossil tree stumps, soils and plant detritus that, until recently, were beneath tens to hundreds of metres of ice. In addition, human artefacts and caribou dung are emerging from permanent snow patches many thousands of years after they were entombed. Dating of these materials indicates that many of these glaciers and snow patches are smaller today than at any time in the past several thousand years.”
3. Goehring, B. M. et al. 2012. Holocene dynamics of the Rhone Glacier, Switzerland, deduced from ice flow models and cosmogenic nuclides. Earth and Planetary Science Letters 351–352, 27–35.
http://academiccommons.columbia.edu/download/fedora_content/download/ac:152773/CONTENT/j.epsl.2012.07.027.pdf
“After 5 ka, the Rhone Glacier was larger than today, but smaller than its LIA maximum extent. The present extent of the Rhone Glacier therefore likely represents its smallest since the middle Holocene and potential climate warming will lead to further rapid retreat of the Rhone Glacier.”
4. B. K. Reichert, L. Bengtsson and J. Oerlemans: Recent Glacier Retreat Exceeds Internal Variability. Journal of Climate 15 (2002) 3069.
http://www.meteo.psu.edu/holocene/public_html/Mann/courses/EVAT795/Reichertal-JClim02.pdf
“Preindustrial fluctuations of the glaciers as far as observed or reconstructed, including their advance during the Little Ice Age, can be explained by internal variability in the climate system as represented by a GCM. However, fluctuations comparable to the present-day glacier retreat exceed any variation simulated by the GCM control experiments and must be caused by external forcing, with anthropogenic forcing being a likely candidate.”
5. O. Solomina, W. Haeberli, C. Kull, G. Wiles Historical and Holocene glacier–climate variations: General concepts and overview. Global and Planetary Change 60 (2008) 1–9
“The finding of the Oetztal ice man in the uppermost part of a small glacier in the Austrian Alps clearly illustrates that Alpine glacier volumes (not lengths!) have become smaller now than during at least the past about 5000 years.”
6. Bakke, J., Lie, Ø., Dahl, S.O., Nesje, A., Bjune, A.E., 2008. Strength and spatial patterns of the Holocene wintertime westerlies in the NE Atlantic region. Global and Planetary Change 60, 28–41
http://folk.uio.no/joh/GEO4011/Bakke_07GPC.pdf
“The retreat of maritime glaciers along western Scandinavia over the last century is unprecedented in the entire Neoglacial period spanning the last 5200 yrs.”
I hope you get the idea and learn a little.

eestorfanfibb

Rud! how’s your nanocarbon business these days? Still moonlighting as a fake earth scientist I see.
Oh BTW, http://web.tmxmoney.com/article.php?newsid=7543763688718673&qm_symbol=ESU

Fibb, how nice to meet you again. And how is your Eestor investment going with the stock at an inflated $0.23? Last I recall, your average cost was >$2. Maybe even >$4, since you were a true believer in that provable fraud.
You got something to say about SLR, say it. Put up or shut up.

Dave Wendt

OSTM/Jason-2 Products Handbook
2.3.1. Accuracy of Sea-level Measurements
Generally speaking OSTM/Jason-2 has been specified based on the Jason-1 state of the art,
including improvements in payload technology, data processing and algorithms or ancillary data
(e.g: precise orbit determination and meteorological model accuracy). The sea-surface height shall be provided with a globally averaged RMS accuracy of 3.4 cm (1 sigma), or better, assuming 1 second averages. …
The following table provides a summary of specifications and error budget at the end of the
verification phase.
Altimeter range: RSS 4.5 cm TBD
RMS Orbit
(Radial component) 10 cm TBD
SSH : Total RSS 11 cm TBD
Significant wave 10% or 0.5 m TBD
height whichever is greater
It is probably worth noting that despite these obvious difficulties the Jason 2 data is likely several orders of magnitude better than the TOPEX/ POSIEDON products even if only the more accurate orbital ephemeris and real time atmospheric corrections are allowed for. Also this is a version from 2009, but I have encountered a more recent version and none of the TBDs has been taken down even though the J-2s are approaching the end of their designed lifespans

Greg

Ristvan re. Jevrejeva 2014

The paper isn’t very credible; it seems a desperate warmunist [3] faux defense of the SLR acceleration belief.

That paper is biased in that it mentions acceleration in the abstract but if you read the paper itself, it points out that the acceleration all happened BEFORE 1900 , so it can not be attributed to AGW.comment image
Jevrejeva has done a thorough analysis but there is definately some spin in the way the results are reported. This would probably pass John Cooks tests as a paper which explicitly supports AGW when in fact the opposite it true.

Chris Hanley

It sounds counterintuitive to me but this quote is from Climate4you (Oceans):
“… Temperature-driven [thermosteric] ocean water expansion will therefore not in itself lead to lateral displacement of water, but only lift the ocean surface locally. Near the coast, where people are living, the depth of water approaches zero, so no temperature-driven expansion will take place here (Mörner 2015). Mechanism 3 [temperature-driven] is for that reason not important for coastal regions”.

Don Graham

The “warmunists” frequently ignore the fact that CO2 ppm have risen dramatically over the past decade or three to 407 ppm. That rise in just our air quality has near and long term consequences which we ignore at our peril; however, it is only one of the 90,000 manmade chemicals floating about in our air and seas.
The disappearance of multiple life forms from the warming of our air, weather systems and oceans is of more than passing concern, especially since some are part of our food chains and resources. Before Claude Levi-Strauss died, NPR reported that his greatest fear was “the poisoning of the planet.”
In 1972, researchers at MIT wrote a paper on the gathering influence our man-made chemicals were having on our food resources. Their research was updated prior to Fukushima with modern technology and data. “Overshoot and Collapse” of global populations from starvation caused by those chemicals was then expected no later than 2024 rather than sometime after 2030.
Their research said nothing about global warming, climate change, pandemics, mass migrations of environmental refugees or conflicts between the “haves” and “have nots” for the “decreasing resources crisis,” particularly of uncontaminated fresh water. Since then, we’ve seen increased concern over that decline in California, our Desert SW and other food production regions of this and other continents on the planet.
That “crisis” was first identified as a contributing factor to the instabilities in Cairo a few weeks after Mubarak was deposed. A few weeks later, it was reported as a contributing factor to the civil war in Syria. As that conflict deteriorated, the locals began to lose hope for their future and became refugees & immigrants looking for a calmer, cooler and damper climate in which they might grow their food and raise their children.
Many overwhelmed their neighbours water resources and kept moving. European resources were quickly overwhelmed, and barriers erected. We’ve not acknowledged such problems in the Americas, yet, although I suspect many immigrants from Mexico are also environmental refugees.
We’ve seen many reports of inadequate snow in the mountains of the West, of melting and disappearing glaciers all over the world. We’ve seen little, if anything, about the contaminated oceans. Ocean acidification gets some play, but no connection to the disappearance of sea food and life forms. Of particular interest to me are those in the Pacific Ocean – from bleached, dead corals in the Great Barrier Reef, to murres along the Alaskan coast to the 5,000 life forms in the northern Salish Sea of British Columbia of which only four remain.
Poisoned or cooked? What’s next? 2

Chris Hanley

You forgot the polar bears — don’t forget the polar bears.

tty

As I live in Europe and have personal experience of these supposed ”refugees” I know that this is all bullshit. A vast majority of them are not from Syria and they are not refugees. They are “social security tourists”, which is why they almost all want to go to Germany or Sweden, which are the only countries that give all migrants equal (or better) social security than natives.
Last November when Sweden’s social security system was collapsing under the strain a new rule was introduced: a refugee now has to show ID papers before entry. Note: there is no restrictions on refugees, anybody may still claim asylum, and everybody coming from a war zone is still granted residence. But you can’t throw away your passport and fake where you come from any longer, at least not as easily
What happened? The number of “refugees’’ dropped by more than 90%.

Johann Wundersamer

Don Graham,
the heat that drives near east refugees is right now topic of civil processes.
Up from 15 ys old everyone owns more than one smart phone and their guiding stars seem to be attractive young woman drinking alco-pops on dance floors or taking selfies while shooting.
If there’s videos about daylong working conditions in Europe thei’re probably not so acquainted with.
Similar may alter view to all your points – doesn’t change your freedom of mind.

Johann Wundersamer

autocorrection knew it better – make
taking selfies while shopping.

Johann Wundersamer

And with vessels, there’s already estimated 3 mil. wrecks in mediterranen sea and atlantic – where 20., 21 ctry numbers is just noise.
http://www.google.at/search?biw=360&bih=264&ei=XxySV8G2IILYgAb46YSQAw&q=estimated+number+of+shipwrecks+in+mediterranean+sea+since+beginning+of+navigation+&oq=estimated+number+of+shipwrecks+in+mediterranean+sea+since+beginning+of+navigation+&gs_l=mobile-gws-serp.12…17492.69034.0.70349.57.57.0.10.10.0.2526.18497.1j37j11j2j7-3j2j1.57.0….0…1c.1.64.mobile-gws-serp..1.28.4472.3..0j41j0i3j0i46i67j0i67j0i22i30j33i21j30i10.fZd7nrPVZ1o

Association between naturally occurring events and consequently in their variability may exist even if the current understanding of such events has no obvious explanation for it.
http://www.vukcevic.talktalk.net/SeaLevel.gif

Dodgy Geezer

Odd bit of grammar here – needs correcting?
…Tide Gauge SLR
The actual rate of sea level rise is uncertain, let alone possibly detectable AGW acceleration….

LdB

I don’t have time for this but the article is way out of date as are most of the climate science websites. The official number for sea level rise is pretty much 2.8 ± 0.5 as per last papers in 2015
http://arstechnica.com/science/2015/05/bias-in-satellite-measurements-hid-recent-sea-level-rise-acceleration/
The data is from directly floating bouys out and checking the measurements from a couple of sites and I am sure if you look you can find the papers.
The cause of the anomalously high Jason 1 and OSTM/Jason 2 absolute biases still remains unknown. To play with the data in climate science you have to model a baseline something that gets lost in the above waffle as I am not convinced the writer understands how it works.
All of that detail is freely available from IMOS and openly disclosed just read the section labelled Application of Data.
http://imos.org.au/srscalval.html

Bob boder

LdB
Up stream you were arguing that the sati lite data is perfectly calibrated, make up your mind or stop posting your drivel.

LdB

Bob it is calibrated so lets give you the fast basic science version which includes no climate science.
If you position one of the satellites over land it measures perfectly even in absolute distances, in fact every commercial aircraft has two radio altimeters on board the calculation is easy
Here is the formula ===> https://en.wikipedia.org/wiki/Radar_altimeter
The problem is when you take an airplane or a satellite over water it doesn’t work. Nothing to do with the waves or anything else if you unfold a reflective sheet … the formula she don’t work. The reading is always high the radio signal appears to reflect higher than the target. It’s an unsolved problem in physics nothing to do with climate science. All aircraft do the same thing but a couple of foot on their altimeter is not an issue they have separation of flight paths of hundreds of feet.
It’s a physical problem absolutely nothing to do with the stupidity called climate science, the writer didn’t even know that. So what they are doing in climate science is constructing usually a relative baseline to get around the problem.
So their baseline they are using is a CALIBRATED reference number it’s not absolute and it can’t be out. In effect the graph is just a relative value construction of the sea surface take off a couple off a foot or so and you are close to what the level probably is in real life.
What surprised me is not a single comment on here could actual give the dumbed down layman version including someone who theoretically studied it enough to write an article. It really isn’t rocket science.

LdB

Actually probably need to clarify that the radar altimeter is the collision avoiding radar on commercial planes they don’t fly by them because of the issues over rough terrain and water. They generally blank the readout from them over 2500ft above the ground. However they are the ones that go “pull up” “pull up” before you slam into a mountain.

LdB

Oh and if you want to play with one Garmin sells one for $14K which is FAA TSO approved but how they deal with water and rough terrain is a commercial secret.
http://www.flyingmag.com/news/garmin-introduces-its-first-radar-altimeter

Bob boder

LdB
nothing you just said has anything to do with what you said up stream. I have worked on thousands of pieces of delicate equipment of all different stripes in my life there is nothing you can say about calibration that is of any value to me. You can calibrate till your head explodes but if the results you get are not useful it means nothing, all you have done is waste time and money. Like you are wasting every bodies time here with your trolling drivel, it’s time to change your name again you have been found out. I’ll give you some advice you need to work on changing your writing style when you change your name again.

LdB

OMG you do instrument calibrations and you don’t get the problem … so lets just tell you the data is SCALING. So 2.6mm slope on the tide gauges is becoming a scaled yet consistent 3.1 mm measurement on the satellite, so how does one get an inaccuracy to scale when working absolute measurements with instruments?
If I ask you to measure a length of an expanding rod as I heat it up and it expands if you are making a measurement error it could be erratic with spiked values or it could just rumble around from the true value but what it won’t do EVER IS SCALE that can only happen in your measurement apparatus. To scale the error has to be systemic and the radar technique is a DIRECT MEASUREMENT it can’t really scale and not at the given rate so the only possible systemic error has to be in the baseline they are constructing.
Now do you know the satellites are calibrated to 3 sites on the earth, I have given you one which is Bass Straight in Australia your challenge is to identify the other two. Now lets give you the final bit they isolated which was in the article above from IMOS and lets quote it
“The researchers found slowly growing mismatches with the tide gauge data that started as soon satellites began measuring sea level in 1993. The gap persisted even if they tried various subsets of tide gauges to rule out extraneous explanations.”
Now put your thinking hat on what happens if I got unlucky with my choice on the 3 calibration sites?
My answer is I think the tidal gauges are right and the climate scientists dorked the calibration sites and IMOS is half way to that answer … watch that space.

Bob Boder

LdB
“OMG you do instrument calibrations and you don’t get the problem … so lets just tell you the data is SCALING. So 2.6mm slope on the tide gauges is becoming a scaled yet consistent 3.1 mm measurement on the satellite, so how does one get an inaccuracy to scale when working absolute measurements with instruments?”
Again you are found out stop trolling you are wasting my time and everyone else’s. Change your name again and troll a different post.

tty

”We know that in the last interglacial, the Eemian, the sea level highstand was about 6.6 meters above present sea level,”
No, not really. The referred paper (Kopp et al. 2009) is very often quoted, but is essentially an elaborate fake. Their “Global database” of Last Interglacial (LIG) sealevels is strange to put things mildly. To be useful for determining LIG sea-levels a site must be in a tectonically stable area, and far enough from a major ice-cap not to have been affected by isostatic adjustments caused by the ice (for LIG sites this applies to both the last and the penultimate glaciations).
So how is it with their 34 sites:
Four (Western Spitzbergen, Scoresby sund, Cape Ross, Nova Scotia) were actually glaciated during the last glaciation and are still rising. The level of LIG coastlines there have no discernable relation to their original level
Seven (Southern England, Bristol Channel, Belle Hogue Cave, Port-Racine, the Netherlands, South Carolina, Bermuda) are in the “forebulge” zone of the Eurasian or Laurentide Ice sheets, and are still sinking. The level of LIG coastlines there have no discernable relation to their original level. This probably also applies to the three sites in the Bahamas (San Salvador, Great Inagua, Abaco), but this is less certain.
Three (Barbados, Red Sea, Oahu) are known to be tectonically unstable (shown e. g. by warping of the supposedly “stable” coastal deposits).
For one site (Wrangel Island) it is quite doubtful if the coastline is even LIG (the referenced publication states that “the possibility remains open that the Krasny Flagian is correlative with the Pelukian or last Interglacial transgression”, my emphasis).
So about half the sites are actually quite useless for determining LIG sea-level. And it seems unlikely that the authors would be unaware of this.
Also the whole paper is based on Bayesian statistics, an inherently subjective method. A minimum requirement in such cases is that the “Prior probability” is explicitly indicated, since it has a very large effect on the resulting “Posterior probability”. However, while they describe how their “Prior probabilities” are derived, they don’t actually show them for any site.
Essentially this paper is a variation of the classical Mannian technique, take a bunch of bad proxy data, chew it up with a liberal dose of doubtful statistical methods, and voilá you have ™Climate Science.

tty

“One paper even said NH SLR is 2.0mm/yr, while SH SLR is only 1.1mm/yr. This peer-reviewed paper would be logically implausible to any 2 year old familiar with bathtubs and water.”
Not necessarily. The world ocean is not a bathtub, and adding a given volume of water to it can have very different effect in different places, depending on where the water comes from due to gravitational effects. If all ice on Greenland melts for example, the result would be lower sea-levels in most of the North Atlantic. If the figures in that paper are correct it simply means that Greenland isn’t losing much ice, if any.

commieBob

I wonder if ‘they’ have considered wave profile. I think most people would assume that ocean waves are sine waves that break down near shore. Reality is different.
Tide gauges are near shore and that’s where the satellites are calibrated. The wave profile in mid-ocean is quite different and constantly changing. I don’t see how ‘they’ can adjust for that.

Here is a list of parameters – measurements and model outputs that are required to enable Jason 2 to return a usable reading.
The number of variables which are needed to be used to achieve a reliable measurement indicate that the error bars on the measurement i.e. height of sea level need to be very large.
Date below from: http://www.ospo.noaa.gov/Products/documents/J2_handbook_v1-4_no_rev.pdf table 8 page 26.
Dry Troposphere Range Correction: From ECMWF atmospheric pressures and model for S1 and S2
atmospheric tides.
Wet Troposphere Range: Correction from ECMWF model.
Sea State Bias Empirical model derived from 3 years of MLE4 Jason-1 altimeter data with version “b” geophysical models.
Mean Sea Surface: CLS01.
Mean Dynamic Topography: CLS Rio 05.
Geoid: EGM96.
Bathymetry Model: DTM2000.1
Inverse Barometer Correction: Computed from ECMWF atmospheric pressures after removing S1 and
S2 atmospheric tides.
Non-tidal High-frequency Dealiasing Correction: Mog2D High Resolution ocean model on (I)GDRs.
Tide Solution 1: GOT00.2 + S1 ocean tide, S1 load tide ignored.
Tide Solution 2: FES2004 + S1 and M4 ocean tides. S1 and M4 load tides ignored.
Equilibrium long-period ocean tide model: From Cartwright and Taylor tidal potential.
Non-equilibrium long-period ocean tide model: Mm, Mf, Mtm, and Msqm from FES2004
Solid Earth Tide Model: From Cartwright and Taylor tidal potential.
Pole Tide Model: Equilibrium model.
Wind Speed from Model: ECMWF model.
Altimeter Wind Speed Model: Derived from TOPEX/POSEIDON data.
Rain Flag: Derived from comparisons to thresholds of the radiometer-derived integrated liquid water content and of the difference between the measured and the expected Ku-band AGCs.
Ice Flag: Derived from comparison of the model wet tropospheric correction to a dual-frequency wet tropospheric correction retrieved from radiometer brightness temperatures, with a default value issued from a climatology table.

tadchem

What is being overlooked here is that (1) SLR is a *local* event – a catastrophe due to SLR in one place may not necessarily affect other coastal areas, and (2) the most catastrophic sea level changes are also local and due to seismic activity – such as the Pacific Northwest of the US in 1700 AD, or Crete in 365 AD, or the temporary SLR of tsunamis.

Are there regional discontinuities in sea level changes? What are the precise displacement affects on lithospheric submersiveness by the weight burdening effects of the Greenland & Antarctic ice sheets? Does the Arctic Ice Cap reduce the buoyancy (range for changes? unanswered) of the Eurasian and North American Tectonic Plates? Thus threatening Northern Hemisphere Coasts & Islands with erosion?

tty

Not abrupt discontinuities, but yes, sea level changes varies a great deal geographically. An icecap raises the sea-level around it by tens of meters due to the gravitational attraction of the ice-mass, so when an ice-cap melts the sea-level actually goes down for a couple of thousand kilometers around.Generally speking if ice on both Greenland and Antarctica melts the sea-level is expected to rise most strongly in Southern Africa and the Central Pacific.

toncul

“There is no doubt that…”
Really ?
Is it possible that we have no doubt about something ?

Yes. About some general things, there is no doubt. What, you think gravity doea not explain planetary orbits? The Laurenride ice sheet did not melt? The dinosaurs did not go extinct? About some things in a general sense, there is no doubt. You think otherwise, please go wondering in a wilderness of your own construct. But not here. Or anywhere in the viscinity

toncul

Oh yes you’re right. I just found another example: there is non doubt that the climate is changing due to human activities.