Heat-driven expansion not a major source of sea level rise
With the power to drown low-lying nations, destroy infrastructure, and seriously affect sensitive coastal ecosystems, sea level rise may be one of the most readily apparent consequences of global warming that is already under way. However, the sources of the rising waters, and the dynamics driving them, are not so clear. Melting land-locked glaciers, shrinking ice sheets over Greenland and Antarctica, and the ocean’s thermal expansion will all play a part, but the expected contribution from each of these sources is still up for debate. Previous studies have suggested that thermal expansion driven by rising sea surface temperatures will account for up to 70 percent of sea level rise in the near future, but research by McKay et al. suggests this may be a drastic overestimate.
The authors draw on paleoclimate records and model simulations of the last interglacial period, when the sea level rose by more than 6 meters (19.7 feet), to isolate the contribution of thermal expansion to sea level rise during a previous period of global warming. The authors found that during the last interglacial period, between 130,000 and 120,000 years ago, the global average sea surface temperature changed between .4 and 1.3 degrees Celsius (-0.7 and 2.3 degrees Fahrenheit). On the basis of research into the temperature sensitivity of thermal expansion, the authors suggest that between .2 and 0.7 m (-0.66 and 2.29 ft) of ocean rise would have been attributable to thermal expansion. With thermal expansion playing such a small role in the pronounced sea level rise during the last interglacial, the authors suggest that the Greenland and, in particular, Antarctic ice sheets may be more sensitive to increasing temperatures than previously thought, with important implications for estimates of future sea level rise.
Source:
Geophysical Research Letters, doi:10.1029/2011GL048280, 2011
http://dx.doi.org/10.1029/2011GL048280
Title: The role of ocean thermal expansion in Last Interglacial sea level rise
Authors: Nicholas P. McKay: Department of Geosciences, University of Arizona, Tucson, Arizona, USA;
Jonathan T. Overpeck: Department of Geosciences, Institute of the Environment, and Department of Atmospheric Science, University of Arizona, Tucson, Arizona, USA;
Bette L. Otto-Bliesner: National Center for Atmospheric Research, Boulder, Colorado, USA.
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Lee Harvey says that once you get a hundred meters down the temperature isn’t going to change a hell of a lot
And if you increase the temperature of that 100 meters by once degree Celsius you will get about 21 mm or a little over three quarters of an inch in sea level rise due to thermal expansion. The Executive summary in chapter 5 of the IPCC’s Fourth Assessment Report tells us that over the period 1961 to 2003, global ocean temperature has risen by 0.10°C from the surface to a depth of 700 m. That works out to about 15 mm or a little over half an inch of sea level rise. Alan D McIntire links us to the current Colorado.edu graph showing recent a decrease in the rate of sea level rise. How about that?
“The authors suggest that the Greenland and, in particular, Antarctic ice sheets may be more sensitive to increasing temperatures than previously thought, with important implications for estimates of future sea level rise.”
And the previous thoughts are: Regarding Antarctica the IPCC’s AR4 in Chapter 10 figure 10.5 shows us that the projections for sea level rise by 2100 from the change in Antarctic ice mass will be negative across the board. Added together with Greenland’s change in ice mass it’s still mostly negative.
Al Gore tells us that sea level is going up 20 feet.
Who are you going to believe?
But Smokey, the warm water is hiding in the cold deepness, don’t you know.
Cooling is a symptom of warming, and work will make you free. Truth is lies,
and black is white, whereas green is really red. This has all been said.
Back ye seas, said Canute the Dane, and the seas didn’t listen to him.
Back ye seas, deign the Canuts, especially Strong & Suzuki, but the
seas will not listen still, perhaps they never will ? The sea has no ears.
Axel says:
August 20, 2011 at 4:43 am
This is ALL speculation, because THERE ARE NO actual witnessed records of ice age temperatures.
——–
Well, I’ve personally witnessed a temperature from the ice age…just this morning. It was 68 degrees F here early this morning in Denver. Since earth is still in an ice age and has been for millions of years, we have lots of actual witnessed records from this current ice age.
jorgekafkazar says:
August 19, 2011 at 12:39 pm
Metal objects frozen into ice don’t remain at a constant level. The weight causes the ice beneath to melt very slowly, letting them sink. The 200′ doesn’t all represent accumulated ice.
Try a bit of science instead of urban myth. To melt ice at -7°C would require a pressure of 1000 kg/cm² or just under 1000 atmospheres of pressure.
http://en.wikipedia.org/wiki/Clausius–Clapeyron_relation
Even the pressure at the base of a glacier isn’t sufficient to melt the ice there. It’s a popular fallacy that ice-skates slide because the pressure on the ice melts it under the blade – they slide because ice is slippery.
I didn’t say there was widespread acceptance that GW is happening. I don’t think many would disagree that it’s warmer now than 100 years ago, however, I think there’s probably a large portion that believe recent warming has reached a plateau and that a large portion of the height of the plateau is due to a warming bias in the instrumental record.
WUWT(Watts Up With That) is a blog, bloggers blog about what blogger’s wish. I don’t speak for Anthony, but for myself, I can read about anything pro-CAGW in the MSM, CAGW get’s enough press without WUWT. Besides, any “study” that examines other “studies” and concludes “It’s worse than we thought” and “accelerating” is most likely going to get torn apart here in short order.
Have you seen the # of views? Obviously there’s a diverse crowd here. A belief in GW(historical) does not necessarily conflict with a belief that the Earth is cooling (currently). I think more accurate summation of the view here would be that warming/cooling is natural and cyclical. There’s probably widespread differences on when / how much / relevance / measurability of any particular attribute of climate such as “global average temperature”.
That’s rich! Banding CAGW with AGW to INSIGNIFICANT GW evidence while ignoring observations that bring into doubt the very core of AGW hypothesis. LOL.
On the temperatures… all this summer the temps have been remarkably cool here- mid ’80s to high ’50s. I hazard to guess this is a swing of at least 5-10 degrees from the average. The normal wind patterns seem to have shifted about 30 degrees. Summer is like late spring here in the Sierras at 4,000 feet. Something is wrong with this. Having to close the windows at night because it’s chilly is a definite sign. I actually have to wear a jacket some nights! The garden got snowed on twice, so this summer’s crop is nill. Our tremendous snowfall filled the reservoirs- and they are still full! I’m chainsawing and splitting more firewood than normal- the last two years are stating to spell a downward trend average temps. Winter temps have been moderate, but heavier snowfall. I don’t want to rant about an ice age, but I don’t see a big global warming thing going on here.
The carbon footprint of this subject is starting to be a concern, though.
Joshua says:
August 20, 2011 at 6:56 am
That paper you linked to is possibly worth a post here, but it was only published a few days ago and the abstract and WP’s hyperventilating coverage don’t seem to be entirely justified by the actual work. The article is paywalled but glancing through the Supporting Online Materials causes me to suspect that author’s baleful conclusions are more a product of analytical methodology than of the examined input studies.
For example, in Tables S1a and S1b the included studies report smaller observed range shifts than the expected range shifts for 12 of 20 of the latitudinal studies and for all 16 of the elevational range shift studies. One of the more interesting entries (no. 17 T. S1a) is for a study from Finland which includes the largest number of species(birds) of any of the included studies. It shows an expansion of range much larger than expected, but that is because the temperature trend in the area was actually negative. The other Tables show that there is rather dramatic variability both within and among the included studies. I’m not a really dedicated number cruncher so I can’t meaningfully criticize the multitude of choices the author’s list in their methodological description, but the sheer number of them hints at numerous opportunities for bias to enter in to the analysis. If Anthony does decide to post on this piece perhaps some of commentary community here who are more in tune with statistical voodoo will weigh in. Until then I’ll have to give this work a very big MAYBE.
Richard gives a good explanation of the insignificance of these predicted temperature scares, versus the actual empirically measured temperature changes. See his lecture, Dr. Lindzen of MIT at the CEI – Real Facts about Climate Change.
[ viddler id=79d667f3&w=545&h=307 ]
More videos like this collated at the website linked to the name “Axel”, in blue, above.
Joshua says; So, then, you disagree with what I am told is the majority opinion here at WUWT?
It depends, Joshua, on what strawman “opinion” you think is in the “majority” here. Just because it did warm doesn’t mean it still is warming, or indeed that warming will recommence in the coming decades. But you seem to think it is, and will. Why, I wonder?
Dave Wendt –
A fair response. I’ll look forward to a reasoned discussion about that study and its findings.
In the meantime, I hope that you subject posts such as those Anthony makes about snowpack in the Sierras, or unexpected appearance of seals in Boston Harbor (with, to my memory, some kind of throw-away line about seals knowing something about scientists don’t about climate change) to the same level of scrutiny.
Bruce –
I have been told by WUWT readers that the majority opinion is that warming is happening, just not in a way that is consistent with theories of AGW. You should take up the question of strawman opinions with those who have originated the opinion.
Seems like WordPress don’t support Viddler in the comments, though it works in articles.
It is all a bit confusing…… http://en.support.wordpress.com/videos/viddler/ 😮
😳
So here is the urls:
some geezer with a beard droning on about insignificance of temperature variations 😉
http://www.viddler.com/explore/ceivideo/videos/121/
some geezer with a mustache droning on about temperature gauges 😉
http://www.viddler.com/explore/heartland/videos/351/
😎
—–
Re Joshua, August 19, 2011 at 5:28 pm
Somewhat guilty as charged. Let me explain. Natural GW? Probably. AGW? Maybe, maybe not. Certain catastrophic AGW? Hardly. So we must respond simultaneously to a cacaphony of assertions representing an array of views. Snow storms in warm places must be noted to confront the constant cry of heat waves, tornadoes, and hurricanes which are asserted by the more radical to be the fulfillment of Gorean prophecy. Yeah, it’s weather, but 20 years ago they predicted no more snow in the currently habitable earth. So the “it’s weather not climate” mantra must be maintained to counter the most ignorant and radical.
As for species moving northward, this should also be inspected from a variety of aspects. We seem to have a fresh synthesis of a number of former studies, probably most of which were funded by way of connecting them to AGW so that there was a built in incentive to find evidence of poleward migration. It all sounds far too simple to be true–the precision of population studies required to ascertain such a result. A one degree T rise represents somewhere around a few dozen miles or a degree of latitude, and all these studies harmoniously report a detected signal of such poleward movement which can be filtered out from all the effects of habitat encroachment and invasive species, etc. We could claim, as the population moves to the sunbelt, the animals find more room in the north.
The point being, I find the whole notion of the ability to detect mass northward migrations across species of just a few miles to be pure nonsense. The sort of made-to-order science which WUWT seems dedicated to eridicating. The poster species of the ignorant fantatics–the polar bear–is one of the safest of all the big canrivores, precisely because it lives so far north, far from people. Tigers on the other hand are in big trouble, seeing as how they presently compete with farmers for space. The notion that GW presents the most clear and present danger to wildlife the world over is a preposterous one, one that only fools can entertain. Odds are it presents no threat whatever. –AGf
Alan D McIntire says:
August 19, 2011 at 5:55 am
Since the discussion is about sea level, there ought to be a link to
http://sealevel.colorado.edu/
Admittedly 1 year is not significant, but it looks like sea levels took a dive in 2011
The same data can be seen here on WUWT at the reference pages, both on the ENSO and Ocean pages. FWIW, the decline in sea level in the Colorado data from 2009 to the present is unprecedented in the whole Colorado dataset from 1993 (albeit < 2 decades only…)
Bob Tisdale is conservatively (and sensibly) giving no emphasis to this decline (see earlier post) attributing it to random noise – but it is becoming interesting.
Majority opinions mean nothing. You’re trying to pigeonhole everyone who visits this site, which is a failed exercise.
Indeed phlogiston, lets also see the
Proudman Oceanographic Laboratory
records from the UK, though they do
list all the World’s known tidal stations.
eg: Newlyn, Cornwall, England.
Sea level variation over the past 30 days.
http://is.gd/iqCnCy
The variation between high and low tide,
ranges from 2 metres to 5 metres, depending
on the position of the moon obviously.
In the Gloss Station Handbook, Newlyn,
we have observations since 1915, with
a change of instrument in 1983 / 84, and
again in 1996.
The tables on this page refer to the earliest
incarnation of themeasuring station & etc.
What we see are two sets of figures. One related to
Ordnance Datum Newlyn (ODN), based on mean
sea level at Newlyn between 1915 and 1921, and
another set based on the Tide Gauge Bench Mark.
Both sets of figure show a small rise of about 1 or 2
centimetres in about 70 years. This is hardly dramatic.
it is about 1/2 a percent of the daily variation at best,
and about 1/10th of a percent at the full moon tide.
https://www.bodc.ac.uk/data/documents/nodb/30932/
There is a marked jump in the “sea level” when the
gauges were changed. This is no surprise though.
Similarly for other UK stations on the whole ….
Though the south east of England is falling,
as the north west of Scotland is rising, due to
delayed glaciative effects ? Additionally several
other UK locations are affected by pivoting, such
as the islands of North & South Uist in West Scotland.
South Uist is sinking as north Uist is rising. So what
the actual “Sea Level” is in these places is moot.
There seems little thant man can do to prevent
South Uist from sinking into the sea, short of
extensive dyke works to a Nederlands scale.
UK Tide Gauge Network – more examples
http://www.pol.ac.uk/ntslf/networks.html
See also
Permanent Service for Mean Sea Level (PSMSL)
http://www.pol.ac.uk/psmsl.html
Global Sea Level Observing System (Gloss Handbook)
http://www.gloss-sealevel.org/station_handbook/
Gloss throws up some perhaps surprising results,
when you look at the adat devoid of “green spin”.
In that flagship of the endangered coral atolls,
Male in the Maldives, we see that it went up by
about 3cm in 5 years, but then fell again by
about 4cm in the next 5 years, since when
it has risen by about 3cm in the last 2 years.
…..according to the chart. http://is.gd/kKJETh
And just how exactly is this supposed to be
related to atmospheric CO2 concentrations,
because once again we see clear cyclic
behaviour with levels falling as well as rising.
In one case probably due to the Moon, and
in another case probaly due to ENSO,
ocean currents, & etc. Yet all the while CO2
concentrations are rising slowly, but
apparently in a more or less linear fashion.
How does the straight line cause a wavey line effect ?
Hmm.
Joshua says:
August 20, 2011 at 2:19 pm
Dave Wendt –
“A fair response. I’ll look forward to a reasoned discussion about that study and its findings.
In the meantime, I hope that you subject posts such as those Anthony makes about snowpack in the Sierras, or unexpected appearance of seals in Boston Harbor (with, to my memory, some kind of throw-away line about seals knowing something about scientists don’t about climate change) to the same level of scrutiny.”
As a general rule I would advise against placing a great deal of confidence in anything which has been or is currently being produced in the field of “climate science”. What epistemilogical sympathies I may have tend toward the “skeptical” side for a number of reasons, but mainly because they provide a deserately needed counterweight to those who would use this illusory “crisis” to advance their political and economic goals. They also seem to possess a much higher degree of humility with regard to their work, being far less inclined to claims that it “proves” anything. To the extent that any of them do indulge in hyperbole about their findings I’m inclined to cut them some slack, given the profound deficit of access to the levers of information that they are forced to operate under. In that regard, if their exagerations were 100 times worse than they actually are they would still be as a spit in the ocean compared to the deluge of climate claptrap that has been the sea we all swim in for a couple decades now.
Even though I admit to possessing a rooting interest in the skeptical viewpoint I don’t “believe” they “know” what is driving the climate any more than the alarmists do. I certainly don’t. I put the words believe and know in quotes because almost the entire human population is incapable of meaningfully differentiating between what they claim to know and what they simply choose to believe. If one feels the need to believe something about the climate the state of the science is so abysmal that an argument can be constructed to support your decision, no matter which of the many speculations about what drives it you choose to embrace. I don’t choose to embrace any of them, but I don’t rise to challenge those who do unless they are also demanding that world embrace draconian “solutions” to illusory problems. If I set my mind to it I could poke enough logical holes in any of the alternative hypotheses about climate that presently exist, to demonstrate that they have not been proven to be correct, but the poor state of the science that allows that also allows that none of them can ever be proven to be entirely wrong. When it comes to the future, the possiblities are endless and the prospects that we can project which will eventuate with any degree of certainty are extremely slim
Sorry, the study mentioned ‘models’.
I stopped reading.
BTW – R Gates, let me get this right: you admit that we’re currently in an ice age and therefore global temperatures have been much higher in the past, before we started producing all those nasty SeeOhToos. Have I understood your admission correctly?
Richard Wakefield says:
August 19, 2011 at 7:22 am
The Greenland Ice Cap looks solid and stable. But it’s not. Much of it is a very slow-moving river of ice. Down at the bottom, where ice meets rock, pressure plus the heat of friction can turn ice back into water. Further up, the ice is plastic. The ice cap moves outwards from the center and eventually ends up back in the ocean.
The relatively constant height of the great ice caps of Greenland and Antarctica is an illusion. It is the result of a balance between constant addition of snow in the middle of the continent/island, and constant ablation of the resulting ice at the edges.
Lke a fly in amber, the Glacier Girl was trapped in that slow river and in some thousands of years it would likely have emerged from a calving glacier somewhere at the edge.
w.
Lke a fly in amber, the Glacier Girl was trapped in that slow river and in some thousands of years it would likely have emerged from a calving glacier somewhere at the edge.
———
Yes, but the depth of their burial was because of accumulated snow turning into ice. The river part is why it was, if I recall, they were several kilometers down stream from their landing co-ordinates. That’s how they were found, by predicting how much they likely were moved down stream. The fact that other artifacts left under and around the planes, which were still there, shows they planes could not have sunk into the ice.
Several months ago this rising oceans business was discussed, and I was able to produce maps showing Manhattan Island when Henry Hudson landed there in 1640, and the extent Lower Manhattan in 2008; about one-third of the of the area occupied by the former World Trade Center Towers would have been in the river in 1640!
Unfortunately, a recent computer malfunction prevents me from showing the views, but as I recall, Anthony posted a similar map showing the growth of the Boston land area since Revolutionary time.
Expand the land area in one place and the sea will necessarily rise in others, all other things being equal.
When will we overcome the fallacy of heralding new science papers as if they are the definitive pinnacle of understanding?
And when the next paper comes out saying that sea level rise isn’t happening, will we be able to refrain from heralding it as the definitive word, even when it contradicts the premise of this post?
Because that happens a lot here – espousing a paper that ‘drives the final nail in the coffin’, and then a little while later giving that plaudit to another one that contradicts the first. This is not good reasoning or even reasonable.
Yes, I will corroborate if that’s necessary.
Water does not expand until +4C. So it melts but still shrinks until that magic temperature.