Sea level rise: “jumpy” after last ice age


Image: Global Warming Art – click. 

See also this recent WUWT story: Freaking out about NYC sea level rise is easy to do when you don’t pay attention to history

From the National Oceanography Centre at the University of Southampton: Global sea-level rise at the end of the last Ice Age

Southampton researchers have estimated that  sea-level rose by an average of about 1 metre per century at the end of the last Ice Age, interrupted by rapid ‘jumps’ during which it rose by up to 2.5 metres per century. The findings, published in Global and Planetary Change, will help unravel the responses of ocean circulation and climate to large inputs of ice-sheet meltwater to the world ocean.

Global sea level rose by a total of more than 120 metres as the vast ice sheets of the last Ice Age melted back. This melt-back lasted from about 19,000 to about 6,000 years ago, meaning that the average rate of sea-level rise was roughly 1 metre per century.

Previous studies of sea-level change at individual locations have suggested that the gradual rise may have been marked by abrupt ‘jumps’ of sea-level rise at rates that approached 5 metres per century. These estimates were based on analyses of the distribution of fossil corals around Barbados and coastal drowning along the Sunda Shelf, an extension of the continental shelf of East Asia.

However, uncertainties in fossil dating, scarcity of sea-level markers, and the specific characteristics of individual sites can make it difficult to reconstruct global sea level with a high degree of confidence using evidence from any one site.

“Rather than relying on individual sites that may not be representative, we have compared large amounts of data from many different sites, taking into account all potential sources of uncertainty,” said Professor Eelco Rohling of the University of Southampton’s School of Ocean and Earth Science (SOES) based at the National Oceanography Centre (NOC) in Southampton.

The researchers brought together about 400 high-quality sea-level markers from study sites around the globe, concentrating on locations far removed from the distorting effects of the past massive ice sheets.

Using an extensive series of sophisticated statistical tests, they then reconstructed sea-level history of the last 21 thousand years with a high degree of statistical confidence.

Their analyses indicate that the gradual rise at an average rate of 1 metre per century was interrupted by two periods with rates of rise up to 2.5 metres per century, between 15 and 13 thousand years ago, and between 11 and 9 thousand years ago.

The first of these jumps in the amount of ice-sheet meltwater entering the world ocean coincides with the beginning of a period of global climate warming called the Bølling-Allerød period. The second jump appears to have happened shortly after the end the ‘big freeze’ called the Younger Dryas that brought the Bølling-Allerød period to an abrupt end.

“Our estimates of rates of sea-level rise are lower than those estimated from individual study sites, but they are statistically robust and therefore greatly improve our understanding of loss of ice volume due to the melting of the ice sheets at the end of the last Ice Age,” said lead author Dr Jennifer Stanford of SOES.

“The new findings will be used to refine models of the Earth climate system, and will thus help to improve forecasts of future sea-level responses to global climate change,” added Rohling.

The researchers are Jenny Stanford, Rebecca Hemingway, Eelco Rohling and Martin Medina-Elizalde (SOES), Peter Challenor (NOC) and Adrian Lester (The Chamber of Shipping, London).

The research was supported by the United Kingdom’s Natural Environment Research Council.

Publication:

Stanford, J. D., Heminway, R., Rohling E. J., Challenor, P. G., Medina-Elizalde, M. & Lester, A. J. Sea-level probability for the last deglaciation: A statistical analysis of far-field records. Global and Planetary Change (Published online, November 2010).

doi:10.1016/j.gloplacha.2010.11.002

About these ads

41 thoughts on “Sea level rise: “jumpy” after last ice age

  1. The new findings will be used to refine models of the Earth climate system, and will thus help to improve forecasts of future sea-level responses to global climate change,” added Rohling.

    OR…natural sea level rise will be used in “models” to predict Human caused sea level rise???

    or am I missing something

  2. This is known for decades!
    A good discovery would be to say where Atlantida was…
    Nonetheless, it is important that alarmists know there was far bigger sea level rise in the past!
    And I as have commented before here, it should be from the CO2 from our far ancestors’ fireplaces. Or maybe from the mammoths methane? Or something in between…
    Ecotretas

  3. Um, 1.5 mm per annum x 100 = 150mm = about 6 inches by 2110, if the linear rate were to be maintained.

    I’m not going to drown after all!!! Horray!

    ( I’m personally not at risk after 2050 at the extreme – have grandchildren tho’)
    (and yes I know the catastrophic scenario of Greenland, land glacier and antarctic melting – but don’t believe it)

  4. Ben Hillicoss says:
    December 1, 2010 at 9:28 am

    The implications are that ice sheets are unstable and prone to sudden collapse. One should not expect that sea level rise under global warming will be a constant x mm per year.

  5. What can be said with certainty about sea level rise is that the rate of rise of the global mean sea level has DECLINED in recent years, as recorded by the University of Colorado at Boulder, from 3.2 mm per year to 3.1 mm per year. That change was quietly posted on their monthly publication of the data without, so far as I know, public announcement or fanfare (it isn’t the kind of news that draws more grant money). See:

    http://sealevel.colorado.edu/

  6. richard telford says:
    December 1, 2010 at 10:05 am

    Why should we assume that the remaining ice sheets are going to melt? Given the temp delta from the recent glacial period to today, and looking at the sigmoid curve of the sea level, why are you assuming the total melt of Greenland and/or Antarctica within a short time period?

  7. WOW, and look at that rise since the end of the last ice age. Engineers have a description for the last few tens of meters … measurement error.

  8. I have seen this graph a number of times and my eye is always drawn to the “Meltwater Pulse 1A”. Since there is no “Meltwater Pulse 1″ and no “1B” can someone say why this called what it is? Why not drop the “1A’? Curious.

  9. Come on Richard Telford!

    Back at the end of the last ice age period.There were vast amounts of Ice overlaying North American and Siberian lands to melt off.Thus making it possible for large sea level increase to proceed when the melting sped up as part of the transition from an ice age to the current interglacial period we live in.

    Today there are not much easy to melt glacial ice left,to be able to cause large increases in sea level rise.In fact it is nearly IMPOSSIBLE for sea level rise to accelerate to a much higher rate.Since there are so little easy to melt ice left to work with.

    Really there are little left beside Greenland and Antarctica to melt away anymore.The vast North American Glacial ice cover overlaying land are ALL GONE,having melted away,to make the sea level rise over 100 meters higher.

    The chart plainly shows that around 8,000 years ago.The melting rate and the sea level increase rate quickly leveled off to nearly a flat line.It has been that way ever since.

    The easy to melt ice took around 10,000 to melt away.By 8,000 BC it was all gone. The reason why the sea level increase rate quickly flattened out to just above zero.

  10. OT
    I have my first body count of 8 people frozen to death so far in the 2010-2011 northern hemisphere winter season. We better get some of that global warming they speak of soon or this winter seasons body count will be larger than last years.

    “Heavy snow and subzero temperatures swept across Europe, killing at least eight homeless people in Poland, closing major airports in Britain and Switzerland and causing hundreds of highway accidents.”

    Heavy Snow Causes Severe Disruption in Europe

    http://www.cnbc.com/id/40447815

    P.S.
    I’m not into eugenics so I really don’t find counting dead frozen bodies very funny. I just think it needs to be pointed out in a very ugly way so people at least ask the question, why is the count going up in recent years? Hint: It’s the sun stupid.

  11. Ecotretas says:
    December 1, 2010 at 9:38 am
    “This is known for decades!
    A good discovery would be to say where Atlantida was…
    Nonetheless, it is important that alarmists know there was far bigger sea level rise in the past!
    And I as have commented before here, it should be from the CO2 from our far ancestors’ fireplaces. Or maybe from the mammoths methane? Or something in between…
    Ecotretas”

    Maybe the Atlanteans were big consumers of fossil fuels? After all, they had a nice long ice age to develop their civilization, where we’ve only had this short interglacial. Oh yeah that’s right, their electromagnetic pyramid power-nodules caused the earth’s axis to slip, triggering the great flood and their own destruction. As you can tell, I delight in internet conspiracy theories. And I thought somewhere below the bermuda triangle was the heart of atlantis. That’s why planes and boats go missing there, the lingering electromagnetic interference from some forgotten antediluvian technology.

  12. Wouldn’t it be nice if modern day scientists could just stick to explaining to us how things seem to be? Einstein told us that E=MC2. We believed him and were happy with that. He did not then take unto himself the role of prophet and tell us what would happen to M if we should carry on a pursuit of E instead of getting ourselves a horse. He knew the dangers of hypothetical extrapolation. He didn’t need to explain that, as Mark Twain had already taken good care of it.

  13. RE: Southampton researchers have estimated that sea-level rose by an average of about 1 metre per century at the end of the last Ice Age, interrupted by rapid ‘jumps’ during which it rose by up to 2.5 metres per century.

    It will have to rise a lot faster than that to keep up with Al Gore’s numbers. ;-)

  14. Ken Harvey says:
    December 1, 2010 at 11:02 am

    But, please, explain us, how is it that if the maximum velocity is that of light, he SQUARED IT?…that’s too much I guess.

    [Please expect some corrections on this comment. Are you sure you want it to remain? 8<) Robt]

  15. from the publication abstract:
    “Even the use of the more ubiquitous mwp-1a in modelling studies has been compromised by debate about its exact age, based upon perceived discrepancies between far-field sea-level records. It is clear that an objective investigation is needed to determine to what level inferred similarities and/or discrepancies between the various deglacial sea-level records are statistically rigorous (or not). For that purpose, we present a Monte Carlo style statistical analysis to determine the highest-probability sea-level history from six key far-field deglacial sea-level records, which fully accounts for realistic methodological and chronological uncertainties in all these records, and which is robust with respect to removal of individual component datasets.”

    “we present a Monte Carlo style statistical analysis” <– hmmm, what does this mean — flip a coin and you've got a 50:50 chance of being right?

  16. richard telford says:
    December 1, 2010 at 10:05 am (Edit)

    Ben Hillicoss says:
    December 1, 2010 at 9:28 am

    The implications are that ice sheets are unstable and prone to sudden collapse. One should not expect that sea level rise under global warming will be a constant x mm per year.

    —…—…—

    Ah, but you are dead wrong. Yes, the earlier sea level rises (see spike 1A for example) were due to sudden losses of land-based ice masses. But, like the fools who talk about a reversal of the Gulf Stream due to melting Greenland ice caps, you are assuming the starting conditions for a mythical massive ice melt are the same as those conditions 14,000 years ago.

    Today, unlike earlier geological eras, has NO 5000 foot-thick glaciers covering Chicago, Alberta, Manitoba, Montana, North Dakota, South Dakota, Idaho, and New England. There can be NO sudden rise in sea levels from melting ice today – because there is NO comparable ice present today. Thus there can be NO reversal of the Gulf Stream regardless of increasing temperatures. But that threat is still used in the CAGW propaganda.

    Yes, we should project no century-long sea level increases 100 years into the future. BUT – today’s CAGW extremists project into the future a theoretical rise (that stopped increasing six years ago), but only after INCREASING that theoretical rise by 50%, THEN projecting that inflated rise for the next 400 years. Even the CAGW alarmists agree that Greenland’s ice cap would require 600 years to melt just half of its area, but we are given photo-shopped propaganda showing New York will be flooded by 20 meters in only 60 years.

  17. The important thing is that today we are wise enough to know the correct sea level is the present level, and should never again be allowed to change. Kind of like the climate.

  18. “Global sea level rose by a total of more than 120 metres as the vast ice sheets of the last Ice Age melted back. This melt-back lasted from about 19,000 to about 6,000 years ago, meaning that the average rate of sea-level rise was roughly 1 metre per century.”

    Could this be the source of the “biblical flood” myths? Could be.

  19. If you look at the graph from 16000 years ago to the present, it looks rather like a hockey stick standing on its handle. Maybe this one can replace MMs debunked stick.

  20. [Please expect some corrections on this comment. Are you sure you want it to remain? 8<) Robt
    It’s OK…how is it C sq.2 ? The first nuke would have blew up the whole Solar System :-)
    Planck was more conservative: E=hv

  21. sunsettommy says: at 10:54 am

    I agree with you. The easiest ice to melt has already been melted.

    Here is an example of one of the many floods that caused the “jumps” in the sea level. There are not many of these events left to happen either.

    The Missoula Floods (also known as the Spokane Floods or the Bretz Floods) refer to the cataclysmic floods that swept periodically across eastern Washington and down the Columbia River Gorge at the end of the last ice age.

    http://en.wikipedia.org/wiki/Missoula_Floods

  22. What effects would these sudden changes in weight distribution as the glaciers melted, have had on the earth’s balance, and thus it’s orbit?

  23. Before that amount of melt water entered the sea must have been very salty, how did all the sea creatures manage? It wasn’t man made so it was all right.
    James

  24. I often point warmists to the graphics showing sea level rise flattening.
    Here is another graphic of post ice age sea level rise.

  25. I would gess that these “jumps” are due to the draining of some of the huge inland sea as the ice dams holding their water in melted.

  26. It seems more likely to me that water levels are due to the displacement of water by the way of continental movement and the ongoing volcanic activity, Lava flowing into the sea, Island creation and erosion, sedimentary build up of thousands of rivers pouring into the sea that form deltas, displacing water, this in-turn can raise water levels in other areas.
    In the north polar region, sea level rise by the way of the melting frozen water (Ice) floating on water is filed under the name by physicists as “Bat-shit crazy” because their is no major displacement of volume or weight.

    The Antarctic Region hasn’t lost any of its Ice (it’s minimal at best) and it hasn’t contributed to a rise in sea level even in the surrounding ocean, coming back to the “nasty poisonous gas” Co2 that is approximately .003% or 300 parts per million, When I hear that this gas is supposedly responsible for more phenomena and has more in influence and impact on our Earth than all the other titanic forces from the Sun, Earths geological activity and the rest of 99.7% of gasses under pressure in our atmosphere combined, It reminds me of the “Butterfly Effect” e.g. a butterfly flapping its wings in South America can affect the weather in London.

  27. Its pretty well established that ~6000 ybp, during the Atlantic, the sea level was 3 to 6 m higher then present. I don’t see that in any of the plots. Am I missing something?

  28. The image at the top is not from the current paper. Follow the links to see some of their work. For example:

    http://www.soes.soton.ac.uk/staff/ejr/Rohling-papers/2010-highq%20file%20Stanford_et_al_2010_GPC.pdf

    (figures are at the end of a 37 page pdf; 2.8 Mb)

    ———————————-

    Jeff in Calgary,

    I posted a link to the Missoula Floods at 11:35, above. There were other lakes in North America as the glaciers melted. The massive weight of the ice depressed the ground and melt-water impounded between the ice front and the terminal moraines. There followed overflow and cutting of channels such that much water then went down the mid-continent via the (now) Mississippi drainage. In the area of (now) Lake Erie the impounded water (Lake Maumee) found a southwest route via the Wabash drainage:

    http://en.wikipedia.org/wiki/Lake_Maumee

    In the area of current Lake Ontario the water (Lake Iroquois) found a route to the ocean via the Mohawk Valley at the southern edge of the ice to the Hudson River Valley near Albany (New York) and that drainage path became the route of the eastern end of the Erie Canal.

    http://en.wikipedia.org/wiki/Mohawk_River

    Lake names and routes can be confusing because the lakes and their drainage routes changed over the several thousand years of the melting.

  29. Jeff in Calgary says:
    December 1, 2010 at 12:44 pm

    It wouldn’t have to be ice. Glaciers would bulldoze huge earthen dams too. Melt water would eventually flow over the dam or work through crevices. The force of flow would finally blow away the dam. There is a hypothesis that the biblical flood was the result of a natural earth dam giving way to allow the Mediterranean to flow into and greatly enlarge the Black Sea, itself a glacial basin.

    cheers,

    gary

  30. If the above graph of post-glacial sea level rise is to be believed, it is interesting that during the Younger Dryas, 13000-11500 yrs ago, sea level rise continued albeit with a temporary decelleration. Global temperatures fell shaprly during the Younger Dryas.

    Thus sea level changes seem to be long term phenomena which do not track temperature changes even on a millenial scale. This puts into perspective the currently observed sea level rise. It doesn’t mean much in terms of recent decadal – century scale global temperature. Linking sea level rise to recent decadal scale temperature increase is probably spurious.

    Looking more closely at rate of change / rise might be more informative however.

  31. Right now I’m worried about other levels rising. We’ve had massive rainfall in Pennsylvania, local TV news said 4 inches at places, with very strong winds, around central PA saw the worst of it and I can personally attest it was bad. The western branch of the Susquehanna River is cresting at Columbia County at 27-28 feet, which is 7 above flood stage. As they are saying, if you had flooding from Hurricane Ivan in 2004 then expect it again.

    This was followed by a dramatic temperature drop (dare I say “unprecedented”?), the one meteorologist said he’d never seen one so steep. So we have flooding, wetness everywhere (it feels very cold outdoors with the humidity and wind), and freezing temperatures coming, 25°F low overnight. Always a good combination to reduce wasteful fossil fuel consumption by vehicles.

    Thankfully this is just weather climate change. Imagine if this had been snow!

  32. phlogiston says:
    December 1, 2010 at 2:57 pm

    If the above graph of post-glacial sea level rise is to be believed, it is interesting that during the Younger Dryas, 13000-11500 yrs ago, sea level rise continued albeit with a temporary decelleration. Global temperatures fell shaprly during the Younger Dryas.

    Thus sea level changes seem to be long term phenomena which do not track temperature changes even on a millenial scale. This puts into perspective the currently observed sea level rise. It doesn’t mean much in terms of recent decadal – century scale global temperature. Linking sea level rise to recent decadal scale temperature increase is probably spurious.

    Looking more closely at rate of change / rise might be more informative however.

    That raises a question I have posed before. In these historical reconstructions to my knowledge there is no way they could account for or even know what the actual volume of the ocean basins were at any given time in history.

    The ocean basins are a complex “bowl” whose volume will change depending on the shape of the floor of the basin. Could it be that a significant millennial scale factor is changes in the average depth of the basin due to plate tectonics and crustal movement, lava extrusions at the ocean ridges etc.

    As the Americas move away from Europe and Africa, they open up an ocean basin (the atlantic) which is on average shallower than the Pacific basin which is simultaneously shrinking.

    Average depth of Atlantic ocean = 3926 m
    Average depth of Pacific ocean = 4282 m

    for every square meter of surface area increase in the Atlantic basin surface area, and simultaneous reduction in the Pacific basin surface area, there should be a net reduction in total basin volume in a ratio of approximately 3926/4282 = 0.91686

    The water has to go someplace so mean sea level would necessarily increase.

    They can “guess” about bottom shape for the basins, but there is no way for them to know about the actual cubic volume of the basins at any given time in the past.

    In the case of the 2004 tsunami event in Indonesia the sea floor moved upward by about 5 meters over a large area. This was a permanent change in the ocean basin shape, and reduced its volume unless some other ocean basin made a compensating change.

    http://earthobservatory.nasa.gov/NaturalHazards/view.php?id=14406

    Add to this all the unknowable values such as how much silt load was washing into the oceans at any given time displacing water as the glaciers melted, it is hard to say that changes in sea level necessarily mean in increase in the water volume in the ocean it could just as easily in part or in whole be due to a change in the ocean basin shape and volume to hold a fixed amount of water.

    To illustrate this, fill a large flat Tupperware container with water to the brim and try to pick it up. As you place your hand under the center of the Tupperware container the force deforms the bottom of the container. The volume available to hold water decreases and the water that used to fit in the container now over flows. Not because the amount of water increased but because the shape of its container changed and its average depth and container volume were reduced.

    Larry

  33. pwl says:
    December 1, 2010 at 11:28 am

    Well its no wonder was Noah 500yrs old before having children. And to think they told us it was only 40 days and nights :-)

  34. hotrod (Larry L) says:
    December 1, 2010 at 5:56 pm

    To illustrate this, fill a large flat Tupperware container with water to the brim and try to pick it up. As you place your hand under the center of the Tupperware container the force deforms the bottom of the container. The volume available to hold water decreases and the water that used to fit in the container now over flows. Not because the amount of water increased but because the shape of its container changed and its average depth and container volume were reduced.

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

    Bravo. Nils-Axel Morner has published on this extensively: A quote from one of his papers:

    Abstract
    “In the last 5000 years, global mean sea level has been dominated by the redistribution of water masses over the globe. In the last 300 years, sea level has been oscillating close to the present with peak rates in the period 1890–1930. Between 1930 and 1950, sea fell. The late 20th century lack any sign of acceleration. Satellite altimetry indicates virtually no changes in the last decade. Therefore, observationally based predictions of future sea level in the year 2100 will give a value of + 10F10 cm (or+5F15 cm), by this discarding model outputs by IPCC as well as global loading models. This implies that there is no fear of any massive future flooding as claimed in most global warming scenarios.”

  35. kalsel3294 says:
    December 1, 2010 at 11:58 am

    When mass is moved closer to a spin axis the rate of spin increases.

    Think of a skater moving their arms in and out.

  36. Interesting and makes a lie of claims that corals cannot grow to keep up with rapidly rising waters. The Great Barrier Reef was not in existence during the last ice age due to sea levels being too low but today it thrives.

  37. I’ll bet that when all that ice melted way back then that there where a heck of a lot of Sun Spots too. Is ice a proxy for Sun Spots? Or versa-visea? If “civilization”, as we currently think we know it, were alive and kicking 14,000 years ago, do you think maybe they’d have a lot of Climate-ists running around talking about CO2 and Urban Development and the loss of beach front property? (Seems, in the long run, the only people with a regular income are RealEstate Agents.)

  38. Andy wrote: “Southampton researchers have estimated that sea-level rose by an average of about 1 metre per century at the end of the last Ice Age, interrupted by rapid ‘jumps’ during which it rose by up to 2.5 metres per century.” This is a grossly inaccurate summary of what the article actually said.

    In their abstract, the authors wrote: “We find that mwp-1a occurred between 14.3 ka BP and 12.8 ka BP. Highest rates of sea-level rise occurred at ~ 13.8 ka, probably (67% confidence) within the range 100-130 cm/century, although values may have been as high as 260 cm/century (99% confidence limit). Mwp-1b is robustly expressed as a broad multi-millennial interval of enhanced rates of sea-level rise between 11.5 ka BP and 8.8 ka BP, with peak rates of rise of up to 250 cm/century (99 % confidence), but with a probable rate of 130 -150 cm/century (67 % confidence) at around 9.5 ka BP. When considering the 67% probability interval for the deglacial sea-level history, it is clear that both mwp1a and 1b were relatively subdued in comparison to the previously much higher rate estimates.”

    The best estimate for the maximum rate of sea level therefore is roughly 1.25 m/century. The 67% confidence interval for these maximum “pulses” about 10% of the maximum rate. The maximum rates are only 15% and 35% higher than the average rate of 1 m/century over many millennia as the last ice age ended. The important conclusion is that previous reports of massive increases melting rates are likely to be wrong.

    The figure of 2.5 m/century is mentioned only in connection with the 99% confidence interval around the maximum rate of sea level rise. The odds of maximum sea level rise being this high or higher are 200 to 1!

    (If the authors were using a normal distribution in their statistical analysis, the 99% confidence interval would represent +/-2.5 standard deviations about the mean and 67% confidence would represent +/-1 standard deviation. In this analysis, however, the 99% confidence interval is about 8-10 standard deviations.)

  39. hotrod (Larry L) says:
    December 1, 2010 at 5:56 pm
    phlogiston says:
    December 1, 2010 at 2:57 pm

    Thanks Larry for this very important perspective. Yet another insight showing how extraordinarily myopic the AGW narrative is, sea level change is observed and any other explanation other than CO2 – AGW simply doesn’t enter these people’s minds.

    This leads to a speculative thought – the cycle of glacial-interglacial correlates with “Milankovich” orbital cycles and oscillations such as that of eccentricity. Could orbital oscillations, precessions etc. affect the tectonic plates and ocean basins? You have a possible scenario for reversing the generally assumed direction of causality – instead of cooling temperatures causing sea level fall during glaciation and vice versa in an interglacial, orbital induced tectonic plate deformation could cause a sea level change which might initiate a climatic shift.

Comments are closed.