[Al_U_Card]

 PassedOut, on 2015-May-25, 10:27, said:

Yes. As your earlier references established indisputably, the rise in sea level has accelerated dramatically since 1880, and is now about 3 times as fast as it was then. Some folks try to deny the acceleration by pointing to shorter term fluctuations but, as you point out, they are wrong to do so.

There is a question about the adjustments made to SLR values. (Glacial rebounds etc.) Latest from Hay and Morrow shows that

Estimating and accounting for twentieth-century global mean sealevel (GMSL) rise is critical to characterizing current and future human-induced sea-level change. Several previous analyses of tide gauge records1–6—employing different methods to accommodate the spatial sparsity and temporal incompleteness of the data and to constrain the geometry of long-term sea-level change—have concluded that GMSL rose over the twentieth century at a mean rate of 1.6 to 1.9 millimetres per year. Efforts to account for this rate by summing estimates of individual contributions from glacier and ice-sheet mass loss, ocean thermal expansion, and changes in land water storage fall significantly short in the period before 19907. The failure to close the budget of GMSL during this period has led to suggestions that several contributions may have been systematically underestimated8. However, the extent to which the limitations of tide gauge analyses have affected estimates of the GMSL rate of change is unclear. Here we revisit estimates of twentieth-centuryGMSL rise using probabilistic techniques9,10 and find a rate of GMSL rise from1901 to 1990 of 1.260.2 millimetres per year (90% confidence interval). Based on individual contributions tabulated in the Fifth Assessment Report7 of the Intergovernmental Panel on Climate Change, this estimate closes the twentieth-century sea-level budget. Our analysis, which combines tide gauge records with physics-based and model-derived geometries of the various contributing signals, also indicates that GMSL rose at a rate of 3.060.7 millimetres per year between 1993 and 2010, consistent with prior estimates from tide gauge records4. The increase in rate relative to the 1901–90 trend is accordingly larger than previously thought; this revision may affect some projections11 of future sea-level rise.

So, more (worse?) than they thought? Especially lately, but then the actual measurements show that relatively, the latest results may be slowing down.



So unsettling this settled science.

[Daniel1960]

 PassedOut, on 2015-May-25, 10:27, said:

Yes. As your earlier references established indisputably, the rise in sea level has accelerated dramatically since 1880, and is now about 3 times as fast as it was then. Some folks try to deny the acceleration by pointing to shorter term fluctuations but, as you point out, they are wrong to do so.

Yes, the global sea level rise is higher today than in 1880. But that is only part of the story. If we examine the long-term data, we see that the sea level rise accelerated around 1930 from its previous rate of a little under 1 mm/yr to its present rate of slightly over 2mm/yr. You are correct to say that some people prefer to deny that the acceleration occurred about 80 years ago by pointing to shorter term fluctuations.

http://facweb.bhc.ed..._to_Present.gif
http://earthguide.uc...evel_recent.png

[PassedOut]

 Daniel1960, on 2015-January-23, 13:25, said:

Can you confidently say that there has been acceleration since ~1880?

 Daniel1960, on 2015-March-18, 09:28, said:

For the past 35 years (at least), the rate of sea level rise has been relatively unchanged around 3 mm/yr.

 Daniel1960, on 2015-May-25, 20:45, said:

Yes, the global sea level rise is higher today than in 1880. But that is only part of the story. If we examine the long-term data, we see that the sea level rise accelerated around 1930 from its previous rate of a little under 1 mm/yr to its present rate of slightly over 2mm/yr.

Quote

Figure 3. Projected global mean sea level rise by 2100 relative to 2000 for the RCP8.5 scenario and uncertainty. Vertical grey bars indicate the 5, 17, 50, 83, and 95th percentiles in the uncertainty distribution.

The rate of sea-level increase has tripled between 1880 and now, and is still accelerating. Of course you can cherry-pick a small segment of the entire record to show an irregularity. That's exactly what you argued against (correctly) in your last post. As shown by this chart from the paper that you gave to explain why you are not concerned about sea level rise, the probability that the rise will stop accelerating is very low.

If you can reference any recent scientific paper that projects no acceleration in sea level rise between now and 2100, I'd like to read it.

[Al_U_Card]

Abstract – 23 February 2011
Sea-level acceleration based on US tide gauges and extensions of previous global-gauge analyses
It is essential that investigations continue to address why this worldwide-temperature increase has not produced acceleration of global sea level over the past 100 years, and indeed why global sea level has possibly decelerated for at least the last 80 years.


http://www.jcronline...ES-D-10-00157.1



==================

Abstract – July 2013
Twentieth-Century Global-Mean Sea Level Rise: Is the Whole Greater than the Sum of the Parts?

………..The reconstructions account for the observation that the rate of GMSLR was not much larger during the last 50 years than during the twentieth century as a whole, despite the increasing anthropogenic forcing. Semiempirical methods for projecting GMSLR depend on the existence of a relationship between global climate change and the rate of GMSLR, but the implication of the authors’ closure of the budget is that such a relationship is weak or absent during the twentieth century.
American Meteorological Society – Volume 26, Issue 13
http://dx.doi.org/10...LI-D-12-00319.1
==================

Abstract – January 2014
Global sea level trend during 1993–2012
[Highlights
• GMSL started decelerated rising since 2004 with rising rate 1.8 ± 0.9 mm/yr in 2012.
• Deceleration is due to slowdown of ocean thermal expansion during last decade.
• Recent ENSO events introduce large uncertainty of long-term trend estimation.]
… It is found that the GMSL rises with the rate of 3.2 ± 0.4 mm/yr during 1993–2003 and started decelerating since 2004 to a rate of 1.8 ± 0.9 mm/yr in 2012. This deceleration is mainly due to the slowdown of ocean thermal expansion in the Pacific during the last decade, as a part of the Pacific decadal-scale variability, while the land-ice melting is accelerating the rise of the global ocean mass-equivalent sea level….
http://www.sciencedi...921818113002397

Perspective

[Daniel1960]

 PassedOut, on 2015-May-25, 22:17, said:

The rate of sea-level increase has tripled between 1880 and now, and is still accelerating. Of course you can cherry-pick a small segment of the entire record to show an irregularity. That's exactly what you argued against (correctly) in your last post. As shown by this chart from the paper that you gave to explain why you are not concerned about sea level rise, the probability that the rise will stop accelerating is very low.

If you can reference any recent scientific paper that projects no acceleration in sea level rise between now and 2100, I'd like to read it.

Looks like someone beat me to it. Anyway you stated that the probability that the rise will stop accelerating is low. Then, let me ask you when you think the acceleration will start? Currently, there is no acceleration, as the rate has been constant over the past 36 years based on the satellite data, and about 80 years based on the tidal gauges.

[PassedOut]

The acceleration has already started and measured between ~1880 and now. During that whole period the rate of sea level increase has tripled. Of course there have been a number of variations along the way, and I don't need to see papers that explain that.

What I'd like to see, and what I asked for, is any recent scientific paper that projects no acceleration between now and 2100. You provided a reference earlier, and the paper you referenced did project considerable acceleration between now and 2100. I read the paper you referenced, and it was well-documented and well-reasoned. It was the paper you referenced that provided the (vanishingly) low probability of non-acceleration between now and 2100, not me. Now you seem to be running from its conclusions.

Could it be that the reason that you haven't provided the reference I requested is that you have none?

[kenberg]

Could you help a guy out here about this acceleration argument?

It sounds from here as if everyone is agreeing that the situation is getting worse. The argument is whether things are now getting worse faster than before or they are getting worse at the same pace as before. Is that right? Are we going to hell in a handbasket or on a jet plane, is that what is being discussed?

Sea levels rising at a steady rate would be bad, right? Both as an event and for what it would signify.

[PassedOut]

 kenberg, on 2015-May-26, 07:34, said:

Could you help a guy out here about this acceleration argument?

It sounds from here as if everyone is agreeing that the situation is getting worse. The argument is whether things are now getting worse faster than before or they are getting worse at the same pace as before. Is that right? Are we going to hell in a handbasket or on a jet plane, is that what is being discussed?

Sea levels rising at a steady rate would be bad, right? Both as an event and for what it would signify.

Sure. It's about the pace with which we need to deal with the problem.

The paper that Daniel referenced was, I gather, for planners who actually need to address the issues of sea level rise, and the time frame was between now and 2100. The most likely rise was around 80 cm, with only a 5% chance of a rise to 180 cm.

But even the 5% chance at the lower end entailed some acceleration. So if there is no acceleration at all, there will be a lot more time to deal with the problem. If there actually is a well-reasoned paper that confirms that thesis, it would be a positive thing.

This post has been edited by PassedOut: 2015-May-26, 08:30

[Daniel1960]

 kenberg, on 2015-May-26, 07:34, said:

Could you help a guy out here about this acceleration argument?

It sounds from here as if everyone is agreeing that the situation is getting worse. The argument is whether things are now getting worse faster than before or they are getting worse at the same pace as before. Is that right? Are we going to hell in a handbasket or on a jet plane, is that what is being discussed?

Sea levels rising at a steady rate would be bad, right? Both as an event and for what it would signify.

Sea level has been risen between 2 and 3 mm/yr for the past 80 years. This is not surprising given the warming that has occurred over that time period. Much of the historical data for sea level rise had come from tidal gauges, posted in this link:

http://www.dauphinis...-rise-graph.jpg

From 1880-1900, global mean sea level was rising at about 1.5 mm/yr. For the next 30 years, it slowed to ~0.5 mm/yr. Then, it acelerated to 2.5 mm/yr from 1930 to 1960. It slowed to 1.5 mm/yr for the next 20 years. Since 1980, the rate has returned to 2.5 mm/yr.

Sea level is still rising. In answer to your question, it is not getting any worse faster than before. Sea level rise closely mimics temperature rise, which can be seen here:

https://kenskingdom....c-1880-2012.jpg

The paper that PassedOut mentions, that I referenced earlier, gives an estimate of the upper limit of sea level rise of 180 cm by the year 2100, which has less than 5% probability of occurring. This is the worst case scenario, which is significantly less than those who are claiming up to 5 meters. The report shows that the most likely upper limit of sea level rise would be 80 cm. Projections of such magnitude come with rather large uncertainies, which in this case is 95 cm. Remember, these are not expected levels of sea level rise. Rather, they are maximums. This rise is slow, and readily accommodated by the appropriate acclimations.

[PassedOut]

 Daniel1960, on 2015-May-26, 10:04, said:

The paper that PassedOut mentions, that I referenced earlier, gives an estimate of the upper limit of sea level rise of 180 cm by the year 2100, which has less than 5% probability of occurring. This is the worst case scenario, which is significantly less than those who are claiming up to 5 meters. The report shows that the most likely upper limit of sea level rise would be 80 cm. Projections of such magnitude come with rather large uncertainies, which in this case is 95 cm. Remember, these are not expected levels of sea level rise. Rather, they are maximums. This rise is slow, and readily accommodated by the appropriate acclimations.

Rather than rely upon your summary of the paper, or my summary of it, it would be best if folks would read the actual paper and draw their own conclusions: Upper limit for sea level projections by 2100.
It's not a difficult paper to read and understand.

[Daniel1960]

 PassedOut, on 2015-May-26, 07:17, said:

The acceleration has already started and measured between ~1880 and now. During that whole period the rate of sea level increase has tripled. Of course there have been a number of variations along the way, and I don't need to see papers that explain that.

What I'd like to see, and what I asked for, is any recent scientific paper that projects no acceleration between now and 2100. You provided a reference earlier, and the paper you referenced did project considerable acceleration between now and 2100. I read the paper you referenced, and it was well-documented and well-reasoned. It was the paper you referenced that provided the (vanishingly) low probability of non-acceleration between now and 2100, not me. Now you seem to be running from its conclusions.

Could it be that the reason that you haven't provided the reference I requested is that you have none?

With regards to the acceleration of sea level rise, this paper shows that the particular sites chosen for the tidal gauge measurements and time periods affect whether the rise shows acceleration or deceleration. Specifically, "at scales shorter than 100-years, the measured tide gauge accelerations are strongly driven by the natural oscillations of the climate system (e.g. PDO, AMO and NAO). At the smaller scales (e.g. at the decadal and bi-decadal scale) they are characterized by a large volatility due to significant decadal and bi-decadal climatic oscillations. Therefore, accelerations, as well as linear rates evaluated using a few decades of data (e.g. during the last 20-60 years) cannot be used for constructing reliable longrange projections of sea-level for the twenty first century."

http://people.duke.e...-013-1771-3.pdf

[PassedOut]

 Daniel1960, on 2015-May-26, 12:08, said:

Therefore, accelerations, as well as linear rates evaluated using a few decades of data (e.g. during the last 20-60 years) cannot be used for constructing reliable longrange projections of sea-level for the twenty first century.

Exactly. One cannot say that the acceleration measured over 120+ years has stopped based on a short interval, even if the interval is current. And, of course, the projection of continued acceleration is based on analyses of the physical processes that raise sea level, not on generalized interim rates.

In the paper we've been discussing, a rise in sea level of over 180 cm by 2100 has less than a 5% chance. On the other side of the coin, a sea level rise of under 49 cm also has less than a 5% chance. To get to the low estimate of 49 cm in 85 years, you need an average rise of 5.7 mm per year, compared to 3.2 mm now. You just can't get there without continued acceleration.

Of course there are uncertainties; that's why the range is large. My opinion is, of course, that even a 49 cm rise would cause serious trouble.

[Daniel1960]

 PassedOut, on 2015-May-26, 13:06, said:

Exactly. One cannot say that the acceleration measured over 120+ years has stopped based on a short interval, even if the interval is current. And, of course, the projection of continued acceleration is based on analyses of the physical processes that raise sea level, not on generalized interim rates.

In the paper we've been discussing, a rise in sea level of over 180 cm by 2100 has less than a 5% chance. On the other side of the coin, a sea level rise of under 49 cm also has less than a 5% chance. To get to the low estimate of 49 cm in 85 years, you need an average rise of 5.7 mm per year, compared to 3.2 mm now. You just can't get there without continued acceleration.

Of course there are uncertainties; that's why the range is large. My opinion is, of course, that even a 49 cm rise would cause serious trouble.

If the maximum sea level rise was only 49 cm, why is that such serious trouble? They are saying that the likely maximum rate over the next 85 years is 5.7 mm/yr. They make no mention of the minimum, average, or range. We can make no presumption of acceleration or deceleration, based on this report. What they are saying is that the worst case scenario is not as dire as some have claimed. They make no mention of the likelihood of the actual sea level rise.

[PassedOut]

 Daniel1960, on 2015-May-26, 14:39, said:

What they are saying is that the worst case scenario is not as dire as some have claimed. They make no mention of the likelihood of the actual sea level rise.

Not so. The paper projects the range of possible levels of actual global sea level rise by one particular year: 2100. The left is minimum, the right is maximum. The probability densities reflect the uncertainties inherent in the problem.

Quote

Figure 3. Projected global mean sea level rise by 2100 relative to 2000 for the RCP8.5 scenario and uncertainty. Vertical grey bars indicate the 5, 17, 50, 83, and 95th percentiles in the uncertainty distribution.

The word "maximum" does not appear on this chart. The text of the paper makes clear that the projections are of the actual sea level rise by the year 2100. And, for planning purposes, the chart illustrates how likely it is that each particular level of sea level rise will actually be reached.

[hrothgar]

 Daniel1960, on 2015-May-26, 14:39, said:

If the maximum sea level rise was only 49 cm, why is that such serious trouble?

It's probably not a serious problem for you. However, life is really going to suck for anyone who lives in Bangladesh, or for that matter anywhere all those millions of Bangladeshi's are going to want to move to.

Please feel free top substitute "Florida" or "the Netherlands" or any one of a bunch of places that get wiped off the map by a foot and a half rise in sea level.

I grew up on the Hudson river. Hate to think what moving the salt front is going to mean

[Daniel1960]

 PassedOut, on 2015-May-26, 15:42, said:

Not so. The paper projects the range of possible levels of actual global sea level rise by one particular year: 2100. The left is minimum, the right is maximum. The probability densities reflect the uncertainties inherent in the problem.


The word "maximum" does not appear on this chart. The text of the paper makes clear that the projections are of the actual sea level rise by the year 2100. And, for planning purposes, the chart illustrates how likely it is that each particular level of sea level rise will actually be reached.

You do realize that rcp8.5 is the worst case of the four IPCC emission scenarios? Whether you call it worst case, upper limit, or maximum is immaterial. They all mean the same thing.

[Al_U_Card]

SEA LEVEL CHANGES IN BANGLADESH
NEW OBSERVATIONAL FACTS
Nils-Axel Mörner
Paleogeophysics & Geodynamics, Rösundavägen 17, 13336 Saltsjöbaden, Sweden,
morner@pog.nu
ABSTRACT
Morphological and stratigraphical observational facts in the Sundarban delta
provide data for a novel sea level reconstruction of the area. This sea level
documentation lacks traces of a global sea level rise. This implies totally new
perspectives for the future of Bangladesh. No longer are there any reasons to fear
an extensive sea level inundation in the near future. Sea level estimates based on
linear trend analyses of tide gauge data should be avoided and seem often to be
directly misleading, as was the case with previous, divergent, claims of a strong
global sea level rise component.


October 28, 2011: "Sea Level Changes in the Indian Ocean: Observational facts" by ICSC science advisor Nils-Axel Mörner, PhD (Sea Level Changes and climate), Emeritus Professor of Paleogeophysics & Geodynamics, Stockholm University, Stockholm, Sweden.
Maldives: "there is no ongoing rise in sea level at all. At about 1970, sea level fell by about 20 cm, and has remained quite stable there after (i.e. for the last 30-40 years)."
Bangladesh: At "the Sunderban delta area in Bangladesh--no rise in sea level. The stratigraphy, morphology, vegetational evolution and habitation record a minor sea level lowering at around 1960, followed by 40-50 years of stable sea level."
Laccadives Islands (India): "the locals are quite aware of the fact that sea level is not at all in a rising mode today, rather that new land has been added, leaving previous shore to become overgrown and invaded by terrestrial plant climbers (just as in the Maldives)."
Goa (India): "there is no ongoing sea level rise, sea level has been stable for the last 50 years or so, sea level fell some 20 cm at around 1960."


But disaster must be just around the corner since all of those RCP 8.5 scenario models are predicting it...just like the pause....ah they didn't "project" it, did they?



Perhaps the soon to be awash Floridians can follow the Dutch example and build some dikes? At a rate of mm/year it could be feasible, if necessary.

[hrothgar]

 Al_U_Card, on 2015-May-28, 08:43, said:

SEA LEVEL CHANGES IN BANGLADESH
NEW OBSERVATIONAL FACTS
Nils-Axel Mörner
Paleogeophysics & Geodynamics, Rösundavägen 17, 13336 Saltsjöbaden, Sweden,
morner@pog.nu
ABSTRACT
M

You do realize that Nils-Axel Morner is also well known for his belief in dowsing?

And he doesn't just beleive that there is no sea level rise in Banglandesh, he denies that there is sea level rise anywhere.
And he'd be able to prove this conclusively if it weren't for those meddling Australians burning down his tree...

http://www.monbiot.c...acular-blunder/

[PassedOut]

 hrothgar, on 2015-May-28, 12:38, said:

You do realize that Nils-Axel Morner is also well known for his belief in dowsing?

And he doesn't just believe that there is no sea level rise in Banglandesh, he denies that there is sea level rise anywhere.
And he'd be able to prove this conclusively if it weren't for those meddling Australians burning down his tree...

http://www.monbiot.c...acular-blunder/

Hilarious article!

Quote

In his Spectator article, Mörner makes much of his research trips to the Maldives. These culminated in a 2004 paper published in the journal Global and Planetary Change. In it, Mörner uses an apparently random series of observations – including the discovery of a skeletal “reef woman” buried in a 800-year-old coral reef – to postulate that sea level rise in the Maldives is a figment of scientists’ imagination. How this paper got published is a mystery that only the journal’s editors can explain.

Have to chuckle at the fact that this kind of evidence makes sense to someone who thinks that G. W. Bush was behind the WTC collapse.

Quote

Mörner also claims in the Spectator article to speak on behalf of the INQUA (the International Union for Quaternary Research) commission on Sea Level Changes and Coastal Evolution, whose members he says are “the world’s true experts on sea level” – as opposed to the IPCC, which he asserts has “hijacked and distorted” the data. Mörner was indeed president of this commission until 2003. However, as documented by the Carbon Brief, INQUA now clearly dissociates itself from Mörner’s views. Current president of the INQUA commission on Coastal and Marine Processes, Professor Roland Gehrels of the University of Plymouth, says his view do not represent 99% of its members, and the organisation has previously stated that it is “distressed” that Mörner continues to falsely “represent himself in his former capacity.”

[Daniel1960]

 hrothgar, on 2015-May-28, 12:38, said:

You do realize that Nils-Axel Morner is also well known for his belief in dowsing?

And he doesn't just beleive that there is no sea level rise in Banglandesh, he denies that there is sea level rise anywhere.
And he'd be able to prove this conclusively if it weren't for those meddling Australians burning down his tree...

http://www.monbiot.c...acular-blunder/

Whether or not you believe him, he has exellent credentials on the subject of sea level.

http://www.indefence...rg/bio2.aspx#a1