From World Climate Report: Sea Level History Lesson
We are sure you’ve heard that sea level is rising? We conducted a web search on “Global Warming and Sea Level” and nearly 3.5 million websites are immediately located. And before you conduct the search yourself, you already know what you will find. The earth is getting warmer due to the buildup of greenhouse gases, the warmer sea water expands causing sea level to rise, and most of all, you will read all about the ice melting throughout the world pouring fresh water into ocean basins causing sea level to rise far more. Alarmists insist that the worst is just around the corner, and the sea level rise will accelerate or even quickly jump to a new level given some catastrophic collapse of large sheets of ice near the fringes of the polar areas. Coastlines will be inundated, the human misery will be on a Biblical scale, ecosystems will be destroyed … this goes on for millions of websites!
But things aren’t really so simple.
The United Nations’ IPCC group presents the graph below (Figure 1) regarding eustatic (or global) sea level over the past 125 years, and as noted by the IPCC and by many others, the rate of rise is definitely higher in the most recent 50 years than the first 50 years of the record. So, it becomes quite possible to suggest that sea level rise is accelerating, and may continue to accelerate in the future. Alarmists can certainly find material in the IPCC document to bolster their claim that sea level is not only rising, but the rate of the rise is increasing.
Figure 1. Annual averages of the global mean sea level based on reconstructed sea level fields since 1870 (red), tide gauge measurements since 1950 (blue) and satellite altimetry since 1992 (black). Units are in mm relative to the average for 1961 to 1990. Error bars are 90% confidence intervals. (figure source IPCC)
Back in August of 2008, scientists from all over the world attended a workshop entitled “Empirical Constraints on Future Sea-Level Rise” and they just published a summary of their findings in the Journal of Quaternary Science. Somewhere along the way, they decided to refer to the group as “PALSEA” for PALeo SEA level working group.
The PALSEA group begins their article noting:
The eustatic sea-level (ESL) rise predicted for the 21st century represents one of the greatest potential threats from climate change, yet its magnitude remains a subject of considerable debate, with worst-case scenarios varying between 0.59m and 1.4m. In general, the basis for this debate revolves around the uncertainties in the dynamical behaviour of ice sheets (such as loss of buttressing through ice shelf break-up or enhanced ice flow through water lubrication of the ice sheet base), which may lead to a nonlinear sea-level response to climate change.
Note that the authors are talking about worst-case scenarios leading to “0.59m and 1.4m”; if the trend of the past 50 years continues (from Figure 1), sea level will rise around 0.20 meters (around 8 inches) by 2100. The PALSEA team notes that measuring sea level can be tricky “Because changes in ice mass will also cause changes in regional (due to gravitational and rotational feedbacks) and global (due to volume) sea level, the changes in sea level at a particular coastline record the difference between vertical motions of the land and sea, commonly referred to as relative sea-level (RSL) changes. Such isostatic effects are a function of the distance from the large ice sheets.”
Now for the good stuff! The PALSEA team states that
Given a broad range of emission scenarios the IPCC AR4 predicted global warming of between 1.18C and 6.48C during the 21st century. The last time that a global warming of comparable magnitude occurred was during the termination of the last glacial period (TI).
Furthermore, they write
Given this evidence for periods of rapid warming during TI, at least some of this warming occurred on decadal to centennial timescales. Because of the general similarity between the magnitude and rate of warming predicted for the 21st century and the warming that occurred during certain periods of TI, it is interesting to consider rates of sea-level rise during TI as a case study of the response of sea level to climate change.
The PALSEA group presents the graphic below (Figure 2) showing three different rates of sea level rise following an increase in temperature. As seen there, sea level could rise exponentially (as suggested by many climate change alarmists), it could rise linearly, or it could rise and then level off (the “asymptoting” curve).
Figure 2. An illustrative sketch of three models (black) for the time-dependent response of sea level to a perturbation in temperature (red) (from PALSEA, 2010).
Here’s what they conclude:
Therefore, we suggest that option 1 (exponential sea-level rise) is extremely unlikely. …An exponential increase in rates of sea-level rise with respect to temperature would result in 21st-century sea-level rise an order of magnitude larger than estimates using alternative patterns of response – it is an important result that the palaeo-sea-level data rule out such a response.
Finally, they write “the palaeo sea-level data suggests that sea-level rise related to current warming may be rapid at first and slow over time.”
Basically, their analysis of what happened in the past favors the “asymptoting” curve that is quite different from the exponential curve favored by those proclaiming the worst is yet to come! Mother Nature showed us in the past how sea level responds to warming – we at World Climate Report are listening!
Reference:
PALSEA (the PALeo SEA level working group: Abe-Ouchi, A., Andersen, M., Antonioli, F., Bamber, J., Bard, E., Clark, J., Clark, P., Deschamps, P., Dutton, A., Elliot, M., Gallup, C., Gomez, N., Gregory, J., Huybers, P., Kawamura, K., Kelly, M., Lambeck, K., Lowell, T., Mitrovica, J., Otto-Bleisner, B., Richards, D., Siddall, M., Stanford, J., Stirling, C., Stocker, T., Thomas, A., Thompson, W., Torbjorn, T., Vazquez Riveiros, N., Waelbroeck, C., Yokoyama, Y. and Yu, S.) 2009. The sea-level conundrum: case studies from palaeo-archives. Journal of Quaternary Science, 25, 19-25.
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blockquote>World Climate Report might be listening but will the warmists?
I don’t know what ‘warmists’ will do, but being a good skeptic, I decided to read the paper myself instead.
As a result, I discovered that the paper discusses various comparative periods of warming, and not just the TI period. Unfortunately, these appear to have escaped the attention of the author at World Climate Report. The author writes, “here’s what they conclude”, and, “finally” – about text in the middle of the article.
Here is the actual conclusion of the paper.
And here is a link for anyone else to read up.
ftp://ftp.wiley.co.uk/bksadmin/supplier44/JQS_Information/JQS%20Issues/2010/JQS%2025_1%20IPCC%20Review%20Special%20Issue/JQS%2025-1/jqs_v25_i1_Rev.pdf
(Article begins page 62)
The WRC author accurately quotes a section from the paper that posits an exponential increase in sea level rise is ruled out. Elsewhere in the paper, it is not ruled out. Interested readers may check out the paper in full to understand the discussion therein.
Tsk – apologies for the bolded post.
Since Greenland and Antarctic ice core temperature reconstructions clearly demonstrate Holocene cooling over the last ten thousand years then the sea level rise must be primarily due to mass contribution from glaciers minus isostatic rebound rather than thermal expansion. This mass contribution appears to respond asymptotically from the TI warming event at the end of the last ice age. In other words current sea level rise is related to a warming event 10,000 years ago.
Here’s an expert’s take on sea level ‘rise’
Professor Nils-Axel Mörner (Former IPCC expert reviewer)
“So, we have this 1 mm per year up to 1930, by observation, and we have it by rotation recording. So we go with those two. They go up and down, but there’s no trend in it; it was up until 1930, and then down again. There’s no trend, absolutely no trend.”
Executive Intelligence Review, June 22, 2007 or pdf
———
“It is true that sea level rose in the order of 10-11 cm from 1850 to 1940 as a function of Solar variability and related changes in global temperature and glacial volume. From 1940 to 1970, it stopped rising, maybe even fell a little. In the last 10-15 years, we see no true signs of any rise or, especially, accelerating rise (as claimed by IPCC), only a variability around zero.”
Select Committee on Economic Affairs Written Evidence [2005]
I am left with the impression that seal levels have stopped their rise since the end of the last ice age. I’m confused! :o(
Whats the worry? By the time the next ice age is going strong the sea levels will be back down the 150 meters they are up now, and Florida will have four or five times more surface area, and nicer weather. No more hurricanes!
I would worry more about the manatees dying in the cold near future and going extinct. Has anyone put any effort to develop some sort of shelter for them the next couple of winters?
Why are the environmentalists not building shelters for them to escape extinction?
Here is the article. You do not seem to need a subscription.
http://onlinelibrary.wiley.com/doi/10.1002/jqs.1270/pdf
“Therefore, we suggest that option 1 (exponential sealevel
rise) is extremely unlikely. Note that if the climate forcing
increased exponentially over time then the sea-level rise might
follow this trend, but the exponential response cannot be
considered a direct function of ice sheet mechanics.”
Thanks, Espen and RT-mod for taking the trouble to reply. Now I take it that the thermal expansion of the sea depends on its average temperature, but a lot of the water seems to be pretty cold, so would it really expand that much? Best wishes, Dave.
theBuckWheat says:
August 10, 2010 at 6:45 am
Just because an area that clearly used to be above water is now submerged doesn’t automatically imply that the sea level rose. It also could be the case that the land fell. For example, Alexandria, Egypt sunk into the sea around the 4th century BC and now lies under about 8 meters of water.
————————————————————————————————
Likewise there is a painting in an upstairs room of Harlech Castle at the top end of Cardigan Bay in Wales which shows the waves crashing at the base of the castle walls.
The painting was done in the 17th Century apparently.
Today the base of the castle wall is about 1km from the beach. A road, railway line and housing occupy the land between the castle and the sea. It’s possible the land has risen in that time, but it doesn’t look like the sea level has.
Packbear: The UK and France may not have had the sea between them but I suspect there was a really big river to cross. The Rhine, aided and abetted by the Seine and the Thames, in summer, would have had to go somewhere.
Here’s a recipe for making new land (for Polar bears).
Take one steep long sloping piece of ground; preferrably in some super cold place; but nice and long and high at the top. Choose only pieces of of land that end at a nice big long Fjord; preferrably straight and with water in it connecting to the oceans, so it can enjoy the benefits of sea level rise.
Deposit a large quantity of ice made from compressed snow; and preferrably a few thousand feet thick; or whatever you feel like; and place it on this sloping ground; so It can slide like an ice skater down into the Fjord, and block most of it, so that not too much sea water can get into the Fjord.
Notice that since the ice slab slopes downwards at the same angle of the piece of ground leading to the Fjord, that once it gets to the edge of the land where it meets the water, the ice starts to partially submerge; displacing a lot of the sea water, which now starts to partially support the weight of the ice slab as it moves farther out into the Fjord, continuously going deeper into the water.
You might try as an experiment installing a theodolite on top of the ice, so you can measure the slope angle as the ice advances out over the water, and experiences a continuously increasing upward thrust from the sea water, which of course is denser than the ice resting on it..
From the change in slope, and the thickness of the ice, you can calculate the average radius of curvature of the bottom of the ice as it gets increasingly bent upwards by the thrust of the sea water. Se level rise should aid in reducing the radius of the bend.
From the Handbook of Chemistry and Physics, look up the maximum tensile strain limit for ice made out of compressed snow.
As the ice slab advances, you can recheck your calculations; and at some point you can start collecting bets on when the sinking ice will reach the failure strain limit, and break off a nice big long piece of Polar bear land for the cute creatures to hunt seals on.
With the oceanic tides sloshing back and forth twice a day; you will likely get a tidal bore rushing up the Fjord under the ice, which will increase the curvature of the bottom of the slab; and make it hard for any7 bettor to remeber whent he last Bear land broke off.
Right up your results in SCIENCE of maybe Wikipedia, and get eady to be cited by all the new Climate Science students who are in school trying to learn why ice keeps falling off slabs of ice that are sliding down Fjords.
The concept is similar to “low hanging fruit” being the easiest and first picked. Glacial ice in low elevations and low latitudes will be most susceptible to warming induced melting. Thus, once the easy-ice has melted the process ought to slow. That’s not hard to figure out.
—————————————————
last termination (TI)
penultimate glacial termination (TII)
3rd last termination (TIII)
and so on
The problem with the word “asymptote” is that it seems so final. That’s because it is introduced (usually) as a curve that approaches a given curve (or line) arbitrarily closely. The idea of a limit as x goes to infinity comes to mind.
However, with regard to sea level, the idea ought not to suggest finality. Rather, sea level may creep upward until it has an inflection point and begins to fall. World ice mass will begin to grow, sea level will decline, the curve will continue until it approaches another limit (or not).
How low can it go?
Jimbo says:
August 10, 2010 at 9:52 am
IPCC don’t like Mørner, because he looks at the real world.
IPCC likes model simulations with buildt in CO2 effects, not real world data.
Remember they have a confirmation bias buildt into their objective paragraph.
How can such an organisation work for science?
The answer is; They can not.
stevengoddard says:
August 10, 2010 at 6:22 am
i love that line about humvees.
it is now generally accepted the sea levels have gone up by some 160 meters in the last 20K years.
however, this indian “Ancient City” is not confirmed YET. NIOT has been unable to provide any new soundings data to prove something resembling a city yet. but, if there was a city, it would be atleast 9000 years old.
http://www.indianwatchdogs.com/forums/showthread.php?t=22518&p=318768
Keith Battye says:
August 10, 2010 at 10:48 am
Likewise there is a painting in an upstairs room of Harlech Castle at the top end of Cardigan Bay in Wales which shows the waves crashing at the base of the castle walls.
The painting was done in the 17th Century apparently.
Today the base of the castle wall is about 1km from the beach. A road, railway line and housing occupy the land between the castle and the sea. It’s possible the land has risen in that time, but it doesn’t look like the sea level has.
The land has fallen in that time. It is far enough south that the isostatic rebound from the last glaciation is making it drop. Someone here did post a little map showing contours of land fall/rise in the British Isles one time – perhaps they could post it again?
The comment about Harlech castle being on the coast in the 17th century made me think. Montreuil sur Mer in France is now many kilometres inland and so is Bruges in Belgium. All of these were established before the 17th century. I also remember seeing in an exhibition in Sydney that the sea was 4 metres higher around Australia at one time (but I cannot remember the date). Is there a consensus about what sea level has been over the last 1000 years? Presumably sea levels rose during the mediaeval warm period and then began to fall again as Greenland became uninhibitable. Sorry I forgot there wasn’t a MWP!
Then I remembered a very good documentary in the UK called the Incredible Human Journey which traced the history of the human race outside of Africa. Genetic markers and the dating of artifacts have established that the second of two groups (the first one appears to have died out) left Africa about 60000 years ago and crossed the dead sea when the sea level was very low. This group moved and expanded and split into factions that populated all the known world. One of these factions apparently crossed from Russia to Alaska along a coastal route which only exists when the sea level is again tens of metres below its current level. They settled North American and then South America.
I find all this interesting since I suspect that these dramatic treks across thousands of miles were not driven by idle curiosity. I suspect that climate change was constantly happening and creating famines in one place or another and forcing these nomadic groups to move on.
So we have strong evidence that the sea level was much lower than it is now and some evidence that it was also quite a bit higher. All these have happened during the short history of modern man and all have been entirely natural. The increase in sea level for the last century seems tiny in comparison.
The chart posted is absolute bull. If you go to real resources the chart is not even close. 5000 years ago the sea level was 9 foot higher than now. Go to a real source.
http://books.google.com/books?id=yt0eAYwqn-QC&printsec=frontcover&dq=sea+level&hl=en&ei=hvFhTNTeMIP68Aa6krT6CQ&sa=X&oi=book_result&ct=result&resnum=7&ved=0CFMQ6AEwBg#v=onepage&q&f=false
page 2
Darren Parker says:
August 10, 2010 at 4:40 am
Or, to put it another way, what is the difference in weight of 1kg of water at 5C and 1kg of water at 15C?
No, wait…..
mkelly
so true and similar here:
http://www.sciencedaily.com/releases/2006/11/061109094732.htm
more likely we have cooling and falling SLs
@Icarus says:
August 10, 2010 at 5:23 am
“…I don’t think any of this is cause for complacency, especially as the article says:
Note that if the climate forcing increased exponentially over time then the sea-level rise might follow this trend……”
Well, in that case, we appoint you to worry about it.
Won’t the melting fresh water sources entering the oceans reduce the carbonic acid percentage? Therefore there’s nothing to see in acidic oceans then.
So I did a web search on “Global Warming and Sea Level” (with the quotes included) and only got 452,000 hits;
http://www.google.com/webhp?hl=en#hl=en&source=hp&q=%22Global+Warming+and+Sea+Level%22&btnG=Google+Search&aq=f&aqi=g1g-m1&aql=&oq=%22Global+Warming+and+Sea+Level%22&gs_rfai=CLq1WUiJiTLPSLaLCzQS5w8zLCgAAAKoEBU_QTecU&fp=d9804d37b84b33a1
WUWT?
So then I did a Google search on Global Warming and Sea Level (without the quotes included) and only got 2,100,000 hits;
http://www.google.com/webhp?hl=en#hl=en&source=hp&q=Global+Warming+and+Sea+Level&aq=f&aqi=g3g-m1&aql=&oq=&gs_rfai=CVtrnZCNiTNz_AZSEygTtl5nAAQAAAKoEBU_QU9aG&pbx=1&fp=d9804d37b84b33a1
WUWT?
I understand that Dr. Stefan Rahmstorf, of the Potsdam Institute for Climate Impact Research in Germany, is on the record for warning the world at the end of September 2009 of an “unstoppable” two meter sea-level increase. This announcement may have been the inspiration for one or more recent works of dramatic fiction.
http://www.reuters.com/article/idUSTRE58S4L420090930
theBuckWheat says:
August 10, 2010 at 6:45 am
Just because an area that clearly used to be above water is now submerged doesn’t automatically imply that the sea level rose. It also could be the case that the land fell.
True BuckWheat and we need to stay away from that sort of “evidence”. For instance, the Peak District, in the UK is a National Park. It was formed 325 million years ago from a tropical lagoon but is now in the middle of England!
http://www.brixworth.demon.co.uk/peak.htm
DaveF: I’m really a layman regarding this matter, but you asked an interesting question, so I searched and found this table:
http://www.kayelaby.npl.co.uk/general_physics/2_7/2_7_9.html
And as you can see, you were right in your assumptions that very cold water will not expand as much as warmer water if the temperature increases with the same amount of degrees: The decrease in density for typical ocean water (35g/kg salt) is much smaller if the temperature rises from 0 to 5 degrees than if it rises from 20 to 25 degrees.