As we surmised in earlier posts, the crozon.colorado.edu website was a test run. Here’s the newest graph from the revised http://sealevel.colorado.edu/
They write about the update:
Welcome to the new webpages from the University of Colorado sea level group! We apologize for the delay in updating our sea level releases, but the transition to these new web pages took longer than we thought. In addition, we have made many improvements to our data (new orbits, new tide model, new corrections) which ultimately had little effect on global mean sea level, but brought us up to date with the latest advances in the field.
One important change in these releases is that we are now adding a correction of 0.3 mm/year due to Glacial Isostatic Adjustment (GIA), so you may notice that the rate of sea level rise is now 0.3 mm/year higher than earlier releases. This is a correction to account for the fact that the global ocean basins are getting slightly larger over time as mantle material moves from under the oceans into previously glaciated regions on land. Simply subtract 0.3 mm/year if you prefer to not include the GIA correction.
You may also note that rate of sea level rise over recent years has been less than the long-term average. This is believed to be due to the recent La Nina’s we have been experiencing, though research on this is continuing. We will soon add a plot to the web site illustrating this effect.
Let us know if you spot any bugs in the new web pages. Thanks for your interest!
Comments welcome.
P. Solar,
Google is your friend. Just click the Cache entry…
Ecotretas
If the above statement [bold] is referring to geological plate subduction [and it is not clear to me that that IS what they mean], it seems to me that this basin enlargement would, on long time scales, be offset by all the natural forces of erosion tending to fill the ocean basins. So why this correction factor?
If you ever see this doctored chart flattening, or God forbid, sloping downward, then prepare yourself for new types of “phenomena” that would make even the darkest Sci Fi lit look like a cake walk. 6 billion starving people are not a pretty sight.
A G Foster says:
May 6, 2011 at 7:44 am
“Lots of misplaced skepticism around here. I see only 2 or 3 posters who understand the problems involved. ”
It seems a lot of the problems involved is a case of understanding just what GMSL actually refers to after all these adjustments.
Many we now need a global mean land level against which to compare it.
I understand the crust of the earth moving up and down. But they also need to take into consideration the displacement of water due to the silt/debris entering the oceans from land, underwater volcanoes, etc.
<B?An Alarmist View of "Glacial Isostatic Adjustment"
The ocean bed’s bigger? I revel!
It means I can say that sea level
Is rising much faster
Than ever! Disaster!
Cry hell, and high water, and devil!
</limerick>
Attacking the question from the other side of the coin, so as to avoid the geoid argument, suppose you set a pan on a sponge next to a table of the same height, and you fill the pan with some water, measuring the water level from the table. You pour in more water and measure the level from the table. But then you realize the pan has sunk in the sponge, and your former measurements did not take into account the sinking pan. So you try to figure out how far the pan sunk, and you add that to your measurement. That’s the “adjustment,” and it’s very reasonable. And you can always distinguish between adjusted and non adjusted measurements. In fact you always have to. –AGF
The GIA adjustment came out of those round table discussions about the travesty that sea levels are NOT going up faster than we thought. Since the whole deal about rising sea levels is that Vanadu and the Ganges delta are going to be inundated, we should stick to the real altimetry of the sea. At least they should state that the low-lying areas are now clearly safe. Hell the Maldives may become under a meter of adjusted water even though they remain high and dry.
During La Nina, global atmosphere temps decrease compared to during El Nino phases of ENSO. This suggests that there is decreased transfer of heat from the oceans to the air during La Nina. Assuming that Solar input to the oceans is unchanged (may not be true depending on secondary cloud cover effects of La Nina/El Nino), then net ocean heat content should rise during La Nina, even though the surface waters are in general cooler in the East Pacific. If net ocean heat content rises during La Nina, then thermal heat expansion should be positive during La Nina.
It would require substantial increase in polar and glacial ice volume to overcome the the thermal expansion effect. It becomes an empirical question whether the thermal expansion or increased ice volumes are greater in their effect on net sea level. It is unthoughtful to simply state that a decreased sea level in recent years is due to La Nina in absence of good data.
That’s a new one.
Sea level drops are due to La Ninas while sea level rises are due to manmade global warming.
Why would a graph of “Mean Sea Level” be corrected apart from to give a stable reference level?
If you want to produce a graph of “delta Mean Sea Level corrected for non-vertical sea-shores” (or anything else) – fine!
But it is NOT a graph of “Mean Sea Level” anymore. This stinks of incompetent science allowed by political interests. Sack incompetent scientists, and keep doing it until we end up with competent scientists with morality.
That GIA correction seems rather dodgy to me. The two major areas of isostatic readjustment in the northern hemisphere (northern Europe and eastern Canada) both have shallow seas at the center of the rising areas (Hudson bay and the Baltic respectively). These seas are steadily being decanted into the oceans as the land rises, so it seems likely to me that the correction for GIA should be opposite to what they claim.
Of course it is possible that the isostatic adjustment under the Greenland and Antarctic Icecaps is going the other way and is large enough to outweigh this. However this is guesswork (a k a modelling) since there is no way of measuring what is happening under the icecaps with sufficient precision.
Publish your base-data aligned with new-and-improved (sic) model adjustments/reconstructions, and disinterested observers will readily determine just what these terminally mendacious hoaxers have cooked up.
But yes, we have no bananas today.
Wonderful … another statistic rendered unusable due to human tampering. You people pay tax dollars for this? I know, I know … glass houses … stones … Aussie governments are just as bad 🙂
1776 No taxation without representation.
2001 No adjustment without scientific justification.
If glacial rebound is reducing sea level rise by .3mm/yr below what it would otherwise be (due to melting and warming etc.), that means that coastal areas have that much less sea level rise to worry about. So there is no point to the “correction”, other than to mislead the public a little about the extent of the problem (if there indeed is one).
Post a graph of GSML, not some hybrid Delta Sea Volume Level.
If you want to plot Sea Volume change, get all the factors, sea floor contour, sedimentation, irrigation runoff, land ice melt rates, barometric profiles, sea water expansion, gravimetric profiles from satellite data, etc…
Adjusting seal level biasing on only one factor does not depict sea surface level relative to ground level. If you want to prove AGW by how much ice is melting and thermal expansion, you need to track sea volume, not sea level. Leave the sea level data alone and get a grant to calculate sea volume.
P. Solar says:”Could anyone with a pre-adjustment copy pastebin it somewhere and post a link?
http://wattsupwiththat.com/2011/05/05/new-sea-level-page-from-university-of-colorado-now-up/#comment-654150
“One important change in these releases is that we are now adding a correction of 0.3 mm/year due to Glacial Isostatic Adjustment (GIA), so you may notice that the rate of sea level rise is now 0.3 mm/year higher than earlier releases. This is a correction to account for the fact that the global ocean basins are getting slightly larger over time as mantle material moves from under the oceans into previously glaciated regions on land. Simply subtract 0.3 mm/year if you prefer to not include the GIA correction.”
This makes little sense because GIA correction is balanced in different areas of the world. When one side sinks the other rises, it doesn’t affect global sea level, only the areas where this occurs. Fair enough this is not actually mentioned as the reason, but how about the change form natural volcanism? Sea levels change over thousands of years also due to changing lands masses under the ocean when igneous rock displaces water from oceanic volcanoes. This easily dwarfs any material moved by flow of the ocean currents, so how can this material lost be larger than material put into the oceans from volcanoes? Where is the evidence which outweighs which? I currently see this as unfounded and not supported by evidence used to alter results to follow predictions.
Buzz Belleville says: “A 100% transparent adjustment based on legitimate observations and folks here are still complaining. It’s not like the Colorado folks are trying to slip one past you.”
You are quite right, but give people a bit of a break. After Climategate etc, there is a huge amount of scepticism about all data. If Colorado Uni are above-board – and I see no reason to suppose otherwise – then I’m sure that will come through here in due course.
Hank Hancock – A quick read suggests that Dr. Peter Bromirski is referring to local sea level, not global.
Look, the problem is to figure out whether the mass of the ocean is changing. To know this you have to keep track of sea level, and you have to know if it’s warming and if the basins are changing. If the mass is not changing, then the ice caps are not melting, on average. LOD history suggests that polar ice is increasing (or that melting has decreased lately), in which case sea level rise remains an enigma, as it was in the last millennium. –AGF
Hey Foster, whats the problem, you can’t talk about the noticeable decline is sea level rise, but you have go off on some GIA tangent, as if you are the leading authority on the subject, so you don’t have to notice that sea levels are declining, even with the GIA correction..
Hows that working out for ya….
Somebody give that guy a binky.
Remember this, satellite altimetry is not an exact science. The data is suspect, the basis function is suspect. Spatial variance causes problems in qualitative measuring.
The whole thing is a guess.
The issue of validity grows exponentially with each correction added to the
super model of sea levels.
How about we go back and look at each individual tide guage in the PSMSL and see if we find any GIA correction there.
“”””” Matt G says:
May 6, 2011 at 1:37 pm
“One important change in these releases is that we are now adding a correction of 0.3 mm/year due to Glacial Isostatic Adjustment (GIA), so you may notice that the rate of sea level rise is now 0.3 mm/year higher than earlier releases. This is a correction to account for the fact that the global ocean basins are getting slightly larger over time as mantle material moves from under the oceans into previously glaciated regions on land. Simply subtract 0.3 mm/year if you prefer to not include the GIA correction.”
This makes little sense because GIA correction is balanced in different areas of the world. “””””
Well it doesn’t make any sense at all. The purported negative effect of sea level rise, is how far underwater New York gets.
So who cares that the rise isn’t as much as it should be, because Joe is filling his swimming pool. All that matters is how much the sea level rises; not what all the gory details are. Where would we be if everybody was making adjustment to come up with a figure that would be correct only if what is happening, is not happening ? Totally asinine to make corrections for anything that is happening, so that the sea level then would not rise at all if those things didn’t happen.
“After Climategate etc, there is a huge amount of scepticism about all data.”
You’re damned right about that.
I’m an engineer and I am massively sceptical about any data coming out of “climatology” (which clearly cannot be regarded as a science).
UEA and other pseudo scientists traded on the reputation of real science which had been built up over centuries – they should be strung up (figuratively, if not actually).
No real scientist could admit to have ‘lost’ the original, raw data. Let alone their other shenanigans (peer review, foi, baseless chicken little claims etc etc).
These clowns have set back science by centuries
To GIA or not to GIA that is the question!
Perhaps a good place to start would be with WHY we care about global sea level in the first place, no? As several have pointed out, in a nut shell, we care because we want to know when to move our house away from the beach (deliberately simplistic and flip).
That being the case, the only thing one should care about is the sea level relative to the land, and the rate of change of said relative sea level. In this case, the GIA is a “good guy”, helping prevent disaster, so adding back an increased rate of rise is an ALARMIST action, ie one undertaken to artificially increase the apparent rate of seal level rise which will certainly be misunderstood by the masses, especially the mass media.
I would say this is typical of the CRY WOLF climate “science” community..