Tuesday, February 03, 2015

The Sea Also Rises RTFR Version

There has been much comment on Hay, Morrow, Kopp and Mitrovica's "Probabilistic reanalysis of twentieth century sea level rise", much of it centered about the finding that sea level rise was slower than thought in the first nine decades of the twentieth century and has really take off since.

Now some, not Eli to be sure, have been mislead about this, and Eli for one would place a reasonable amount of blame for some of this on the authors, but, of course, others have pitched right in.  For starters the abstract and the paper push the conclusion

Here we revisit estimates of twentieth-century GMSL rise using probabilistic techniques9, 10 and find a rate of GMSL rise from 1901 to 1990 of 1.2 ± 0.2 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 3.0 ± 0.7 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.
 Of course, any such calculation depends on a better reading of the intermittant, spotty and just plain strange tidal guage record and other some such before 1990 when satellite measurements became available, both for themselves and for calibration of sea level gauges.

Eli has some experience in this sort of stuff having suffered through the late John Daly's Isle of the Dead tidal sage whose echoes can be found even today.  Daly and his fellow rejectionists succeeded in stirring up enough of a furor that it provoked an official investigation, which, of course, found that Daly was, shall Eli say, indulging in ahistorical fiction.

Make no mistake about it, Hay, et al. have made a major advance in methods
In this Letter, we revisit the analysis of GMSL since the start of the twentieth century using Kalman smoothing. This statistical technique naturally accommodates spatially sparse and temporally incomplete sampling of a global sea-level field, provides a rigorous, probabilistic framework for uncertainty propagation, and can correct for a distribution of GIA and ocean models.We applied the approach to analyse annual records from 622 tide gauges included in the Permanent Service for Mean Sea Level (PSMSL) Revised Local Reference database and reconstruct the global field of sea-level change for each year from 1900 to 2010.
and, of course, they can check their tidal gauge record against  satellite measurement in the most recent parts of the period of study as well as making many consistency checks.  Finally their results appear to close the balance
This estimate closes the sea-level budget for 1901–90 estimated in AR5 (ref. 7) without appealing to an underestimation of individual contributions from ocean thermal expansion, glacier melting, or ice sheet mass balance. Moreover, it may contribute to the ultimate resolution of Munk’s sea-level enigma (defined by the argument that Earth rotation measurements and bounds on ocean warming are inconsistentwith a rate of sea-level rise beginning in the late nineteenth century of 1.5–2.0 mm/yr), since it may lower the signal of twentieth century ice melting in Earth rotation measurements.
But, knew there was going to be a but, dinna you?  The take home for Eli which he has not seen much commented on is Figure 4.

 It is not that sea level rise from tidal gauges was a constant ~1 mm/yr or that the rate suddenly accelerated in the 1990s, but it is more complicated than that which is Eli's point.  The impression left by much of the to and fro has been that there was a constant amount of sea level rise until 1990 when it jumped.

Not the case.  The rate varied with a period of ~ 40 years or so (dangerous because the smoothing is over a 15 year period, before starting to grow systematically in the late 1960s (remember the 15 year average).  The insert shows that the most recent times have been the periods of largest sea level rise.  The satellite era tidal gauge record from Hay et al, matches well on the satellite measurements, while the tidal gauge measurements before 1990 are lower than previously thought but show the same sort of variation. (from SKS)

Added on afterthought: The rise per year is a rate, the slope of the line is the acceleration.  From this plot bunnies can say that the acceleration has been monotonically postive since ~1960 and not far off from lines, implying polynomially growth in sea level.  


Taylor B said...

Here's a link to the source of the final graph:

Everett F Sargent said...

Well that 1st graphic isn't too encouraging, slap 2 sigmas on that baby, and the entire US Navy (all vessels to date + 1000 years into the future) could go straight through that entrance channel at the exact same time! Talk about a wide birth, err berth.

But seriously, who cares about the global sea level? (yes, I know, it is important)

After all, I'm pretty sure we all mostly live on or near land, most of the time, say to six sigma even.

So, in keeping with that "I'm a flatlander" shoreline theme, perhaps it is the RSL at the shoreline (and it's rate of change, real and projected) that we are most interested in, at least one would think so, if one were say a coastal engineer working (or who had once worked) for the USACE.

So maybe, just maybe, one woulda, coulda, shoulda compare the satellite data AT THE SHORELINE with the tide gage records that, you know, are mostly AT THE SHORELINE!

You know, just sayin' :-(

Everett F Sargent said...


Thought you might be interested in the latest from NC:

http://www.nccoastalmanagement.net/web/cm/sea-level-rise-study-update (official)
http://wiseenergy.org/current-news/ (political)

As to the 2nd link note the fake-climate blogs at the bottom.

To get to a list of PDF documents on that website you deed to Google this site as:


That will return ~32 PDF documents.

Burton makes a couple of appearances, but I really liked this one:


With UCS member Kenji Watts the Insult Climate Dog.

Fernando Leanme said...

I can't help myself:

Bologna University

Founded in 1088, Bologna University has been student-centred whilst attracting prominent figures from science and the bs arts. Today it is a leader in the European Higher Education Area and famous for its beauty and integration with the city. Its teaching catalogue is diversified and tailored to the needs of present-day society: For example, we offer over 200 degrees in statistical manipulation to achieve the results desired by our sponsors.

The calibre of its graduates, its internationally renowned teachers and its quality research give it a competitive edge, especially in the job market for climatologists.

Bologna has always favoured a multi-disciplinary, cross-cultural approach; it invests in international, multicultural training, research and services. It has formed knowledge alliances with Chinese industry and USA and EU public/private organizations, and is a hub of international conspiracy networks. Bologna enjoys multiple international connections, with famous global warming institutes.

Russell Seitz said...

Do the ancienct academic officers of the University of Bologna include a Detectore ?

Or do they make do with a Pervaricator, as Cambridge, does, to deetect and chastise baloney emission by the faculty ?

Taylor B said...

Re: Eli's added afterthought, sorry to be pedantic but I think it refers to the first graph (Figure 4 from Hay et al.), which differs interestingly from the second figure from SKS over the post-1960 time period referred to in the afterthought.

In order to determine the true rate of acceleration in sea-level rise since 1960, wouldn't you need to subtract the ~40-year periodic variation from the positive slope since ~1960? The second graph indicates a dip from ~1980-2000, when you'd expect the periodic variation to be downward-sloping, but in Fig. 4 (the first graph) it was still increasing at a slower rate. That would imply a significantly greater acceleration than you'd get by just directly reading the slope from Fig. 4. since 1960.

Taylor B said...

I should have noted both the positive and negative contributions of the ~40-year periodic variation in the slope of Fig. 4 since ~1960, which need to be subtracted to get the anthropogenic signal.

Dano said...

IMHO we need a John Daly these days, a sort of loopy, off-kilter sort. Much more entertaining than the deniers and disinformers we are stuck with now.



Fernando Leanme said...

Sorry, I laughed so hard when I saw the plot, my eyes filled with tears, and I had to run clean them out. This made me enter my manic creative phase.

Returning to the science, I assume the oscillations are caused by vertical energy transfer, ie the heat moves from a shallower layer into a deeper layer, and viceversa?

EliRabett said...

Thanks Everetteindeed much fodder there on the outer banks

Fernando Leanme said...

Indeed. I got so excited by this finding I went and wrote my own paper about temperature reanalysis.

caerbannog said...

I took a quick look at http://www.wiseenergy.org/Energy/SLR/Burton_CRC_Panel_comments_2014-11-19.pdf

I liked this bit:

Thermal expansion in the upper layer of the ocean (due to warming or freezing) causes a “bump” in the ocean, but it doesn't change sea-level elsewhere.

It changes average sea surface heights measured by satellites, but it doesn't affect the coasts, and isn't registered on tide gauges.

Mal Adapted said...

Everett: "http://www.nccoastalmanagement.net/web/cm/sea-level-rise-study-update"

The reference to the " 2010 CRC Terminal Groin Study" made me a little queasy...

Nope, still not a robot.

Taylor B said...

As Eli says, fodder a-plenty!

Sea-Level Rise Study Update: "The CRC’s charge to the panel is to conduct 'a comprehensive review of scientific literature and available North Carolina data that addresses the full range of global, regional and North Carolina specific sea-level change.' The CRC further directed the panel to limit the scope of the study to a 30-year rolling time table, to be updated every five years."

In other words, the CRC's charge is consciously self-contradictory and self-defeating.

Fernando Leanme said...

I wish to expand on that earlier quote:

"Thermal expansion in the upper layer of the ocean (due to warming or freezing) causes a “bump” in the ocean, but it doesn't change sea-level elsewhere (for example, sea level in the Caspian isn't impacted if the tropical Pacific water column warms up by 1 degree C and raises sea level in the tropical Pacific).

It changes average sea surface heights measured by satellites, but it doesn't affect the coasts (the coasts are fixed to the continents, and they don't move as sea level rises, they simply get covered by a little bit of water) and isn't registered on tide gauges (because the tide gauges measure tides).

bluegrue said...

Off-Topic: The judgement Weaver vs. NP is in. Weaver won, but the judge found no malice.

Neil said...


Where did the bit "because the tide gauges measure tides" in your last message come from? It doesn't seem to be in the Burton document. It is wrong. Tide gauges measure sea level at high enough frequency to resolve the tidal signals, but inevitably also measure changes in the lower frequency mean.

What Burton says about satellite altimeters seeing the thermal expansion signal, but tide gauges not seeing it is nonsense. Like quite a bit of other stuff in that document.

All his stuff about GIA is wrong too.

Some of you (possibly including Everett) may find this paper: http://www.sciencedirect.com/science/article/pii/S0012825214000956 of interest.


Taylor B said...

Nice pun, Fernando ("expand on an earlier quote")!. But, umm, freezing of water into ice isn't thermal expansion, it's a phase change. The Caspian Sea is an enclosed inland body of water, so it doesn't contribute to SLR. It may also come as a surprise to Burton and a few others that thermal expansion of water doesn't occur only in the vertical dimension.

Hank Roberts said...

Some guy at RC who identifies himself as a former believer in global warming asked a pertinent question -- how is the water mined from aquifers that ends up in the ocean counted toward sea level rise.
He had a number; I find various other numbers out there, but all in the ballpark suggesting runoff from pumped groundwater has up til recently been comparable to glacial melt. Anyone know?

This is much cited:
Past and future contribution of global groundwater depletion to sea‐level rise
DOI: 10.1029/2012GL051230
Geophysical Research Letters >
Vol 39 Issue 9

"... In the IPCC fourth assessment report [Intergovernmental Panel on Climate Change, 2007], the contribution of non-frozen terrestrial waters to sea-level variation is not included due to its perceived uncertainty and the assumption that negative contributions such as dam impoundment compensate for positive contributions (mainly from groundwater depletion). However, recent work on global groundwater depletion [Wada et al., 2010; Konikow, 2011] suggests a rapid increase of this positive contribution to sea-level rise during the last decade that warrants a re-appraisal of the contribution of terrestrial waters and in particular groundwater depletion to projected 21st century sea-level change...."

Neil said...


This: http://onlinelibrary.wiley.com/doi/10.1029/2011GL048794/abstract should shed some light on this. There are at least three different estimates that have come out in recent years, the one you linked to, one by Konikow (also in GRL) and one in Pokhrel et al (not sure which journal). They are all fairly different, and the second one by Wada et al is smaller than the first. This is still a fairly new area.

There should also be some discussion of this in the IPCC AR5.

An offsetting effect is the retention of water in dams, especially in the second half of the 20th century,

Tide gauges and satellite altimeters measure the total sea-level change. Aquifer mining is now being taken into account in sea-level budget estimates.


Everett F Sargent said...

Neal (White?),

Thanks for the link, will read the (your?) paper.

As to the NC shakedown, I know one of the science board members, as well as Houston and Dean (whom are the NC20 'sea level is not accelerating (in the strict quadratic polynomial sense)' go to emeriti, fortunately these two are mostly harmless at the federal planning level. I do not associate myself with their sea level rise views in any way-shape-manner-form (they both have deep connections (for several decades) with the ASBPA/FSBPA)).

Taylor B said...

I'd think the dam storage term would reach near steady-state unless dams continue to be built at a faster rate than they are retired or silt up and become non-functional. Groundwater pumping is increasing in many drought areas, which requires quite a lot of energy for pumping that increases as aquifers are depleted. Eventually, I'd expect groundwater extraction would also reach a near steady state or decrease as the aquifers are overdrawn. Assuming that recharge takes on the order of decades to centuries, this might involve taking many acres of farmland out of production as groundwater becomes too expensive to extract. Just a few thoughts, fwiw, not from any of the sources Hank and Neil mentioned.

Neil said...


In fact, dams are being decomissioned and this term is decreasing. The silting issue is important (and a bit controversial) too.

What you say about groundwater extraction is correct. It becomes harder and more expensive to extract, and recharge is very slow and, in some cases nonexistent ("fossil aquifers").

There was a paper on GRACE measurements of groundwater extraction in norther India a few years ago (http://onlinelibrary.wiley.com/doi/10.1029/2009GL039401/full). The long term consequences of groundwater being extracted faster than it can be replaced are scary!



Fernando Leanme said...

Let's see: I wrote the followng, so I'm going to quote myself:

"It changes average sea surface heights measured by satellites, but it doesn't affect the coasts (the coasts are fixed to the continents, and they don't move as sea level rises, they simply get covered by a little bit of water) and isn't registered on tide gauges (because the tide gauges measure tides)."

Please focus on the fact that coasts are fixed to the continents. They can't change. What happens is that a little bit of water covers the coast, and we get a new coast line. But the rocks don't change.

Cervantes would have called it "una parodia". .

Hank Roberts said...

Neil, much appreciate your comments here. I've lived in areas where pumping caused aquifers to collapse, precluding any later refill (that's definitely on the Stupid Human Foolishness list, a behavior required by law -- if you stop pumping you lose your prior water right and can't reclaim that priority later on, under water law most places, a true race to the bottom quite literally).

That paper for reference is at
DOI: 10.1029/2011GL048794
Geophysical Research Letters
Volume 38, Issue 18, 28 September 2011
and the corrections

Seems to me there would have been a pulse of water during the centuries Bill Ruddiman focuses on too? As we're learning how much erosion human agriculture has caused -- much in the news lately:

I think ReCAptcha is becoming sentient again. Its words for this are: "revised atusdam"

Taylor B said...

Actually, Fernando, much of what you quoted was written by Dave Burton in his comments to the NC CRC Science Panel, who points to the tip of an iceberg as an example of "locally elevated sea level" caused by thermal expansion (see Everett's first comment for the link). It's important to identify your source ("una parodia").

Since you're unconcerned by a "little bit of water," I recommend you invest in Miami real estate, but soon, before it's underwater.

Hank, re: sentient recaptcha, I got "you suicity."

Taylor B said...

I should've pointed to Everett's 2nd, not his 1st comment. Mea culpa! Anyway, here's the easy link again to Dave Burton's most excellent example of thermal expansion of water.

Neil said...

Fernando said: "...they simply get covered by a little bit of water) and isn't registered on tide gauges (because the tide gauges measure tides)".

OK, a bit more water covers the bit of coast, and a tide gauge attached to that bit of coast will record an increase in sea level. A tide gauge is just a device (usually attached to the land) which measures the height of the sea surface above some land-attached datum point.


Hank Roberts said...


from http://www.theguardian.com/environment/gallery/2008/jul/23/climatechange.scienceofclimatechange