However, other analyses show the opposite…
Correcting estimates of sea level rise
Acceleration in sea level rise far larger than initially thought
The acceleration in global sea level from the 20th century to the last two decades has been significantly larger than scientists previously thought, according to a new Harvard study.
The study, co-authored by Carling Hay, a post-doctoral fellow in the Department of Earth and Planetary Sciences (EPS), and Eric Morrow, a recent PhD graduate of EPS, shows that previous estimates of global sea-level rise from 1900-1990 had been over-estimated by as much as 30 percent. The report, however, confirms previous estimates of sea-level change since 1990, suggesting that the rate of sea-level change is increasing more quickly than previously believed. The new work is described in a January 14 paper published in Nature.
“What this paper shows is that sea-level acceleration over the past century has been greater than had been estimated by others,” Morrow said. “It’s a larger problem than we initially thought.”
“Scientists now believe that most of the world’s ice sheets and mountain glaciers are melting in response to rising temperatures.” Hay added. “Melting ice sheets cause global mean sea level to rise. Understanding this contribution is critical in a warming world.”
Previous estimates had placed sea-level rise at between 1.5 and 1.8 millimeters annually over the 20th century. Hay and Morrow, however, suggest that from 1901 until 1990, the figure was closer to 1.2 millimeters per year. But everyone agrees that global sea level has risen by about 3 millimeters annually since that time, and so the new study points to a larger acceleration in global sea level.
“Another concern with this is that many efforts to project sea-level change into the future use estimates of sea level over the time period from 1900 to 1990,” Morrow said. “If we’ve been over-estimating the sea-level change during that period, it means that these models are not calibrated appropriately, and that calls into question the accuracy of projections out to the end of the 21st century.”
To obtain their improved estimate of 20th century global sea level, Hay and Morrow approached the challenge of estimating sea-level rise from a completely new perspective.
Typically, Hay said, estimates of sea-level rise are created by dividing the world’s oceans into sub-regions, and gathering records from tide gauges – essentially yard-sticks used to measure ocean tides – from each area. Using records that contain the most complete data, researchers average them together to create estimates of sea level for each region, then average those rates together to create a global estimate.
“But these simple averages aren’t representative of a true global mean value” Hay explained. “Tide gauges are located along coasts, therefore large areas of the ocean aren’t being included in these estimates. And the records that do exist commonly have large gaps.”
“Part of the problem is related to the sparsity of these records, even along the coastlines,” Morrow said. “It wasn’t until the 1950s that there began to be more global coverage of these observations, and earlier estimates of global mean sea-level change across the 20th century were biased by that sparsity.”
“We know the sea level is changing for a variety of reasons,” Hay said. “There are ongoing effects due to the last ice age, heating and expansion of the ocean due to global warming, changes in ocean circulation, and present-day melting of land-ice, all of which result in unique patterns of sea-level change. These processes combine to produce the observed global mean sea-level rise.”
The new estimates developed by Hay and Morrow grew out of a separate project aimed at modeling the physics that underpin sea-level “fingerprints” – explainer from previous story.
“What we were interested in – and remain interested in – was whether we can detect the sea-level fingerprints we predicted in our computer simulations in sea-level records,” Morrow said. “Using a global set of observations, our goal has been to infer how individual ice sheets are contributing to global sea-level rise.”
The challenge, Hay said, is that doing so requires working with a “very noisy, sparse records.”
“We have to account for ice age signals, and we have to understand how ocean circulation patterns are changing and how thermal expansion is contributing to both regional patterns and the global mean,” she explained. “We try to correct for all those signals using our simulations and statistical methods, then look at what’s left and see if it fits with the patterns we expect to see from different ice sheets.”
“We are looking at all the available sea-level records and trying to say that Greenland has been melting at this rate, the Arctic at this rate, the Antarctic at this rate, etc.” she continued. “We then sum these contributions and add in the rate that the oceans are changing due to thermal expansion to estimate a rate of global mean sea-level change.”
To their surprise, Hay said, it quickly became clear that previous estimates of sea-level rise over most of the 20th century were too high.
“We expected that we would estimate the individual contributions, and that their sum would get us back to the 1.5 to 1.8 mm per year that other people had predicted,” Hay said. “But the math doesn’t work out that way. Unfortunately, our new lower rate of sea-level rise prior to 1990 means that the sea-level acceleration that resulted in higher rates over the last 20 years is really much larger than anyone thought.”
###
[UPDATE] My sub-oceanic source has sent me a copy of the actual study. Here is the abstract:
Estimating and accounting for twentieth-century global mean sealevel (GMSL) rise is critical to characterizing current and future human-induced sea-level change. Several previous analyses of tide gauge records1–6—employing different methods to accommodate the spatial sparsity and temporal incompleteness of the data and to constrain the geometry of long-term sea-level change—have concluded that GMSL rose over the twentieth century at a mean rate of 1.6 to 1.9 millimetres per year. Efforts to account for this rate by summing estimates of individual contributions from glacier and ice-sheet mass loss, ocean thermal expansion, and changes in land water storage fall significantly short in the period before 19907. The failure to close the budget of GMSL during this period has led to suggestions that several contributions may have been systematically underestimated8. However, the extent to which the limitations of tide gauge analyses have affected estimates of the GMSL rate of change is unclear. Here we revisit estimates of twentieth-centuryGMSL rise using probabilistic techniques9,10 and find a rate of GMSL rise from1901 to 1990 of 1.260.2 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 3.060.7 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.
Regards to all,
w.
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Have they EVER said “this is less than we thought and not as big a problem as we thought”?
Of course not. There’s no grant money for anything like that.
I’m still trying to understand why a sea level rise of less than one foot per century is considered a problem, yet alone a “bigger problem than we thought”. Can anyone explain?
Because if you aren’t kept in a constant state of alarm about the monster under the bed, you won’t clamor for government to do something about it and willingly give up your freedoms.
Darned oceans! They are not rising fast enough, based on direct measurements. Therefore, we will TELL those pesky oceans they are rising at the politically correct rate.
I’m not sure why anyone would think it’s easier or more accurate to use the sparse tide gauge measurements than the nonexistent ice sheet melting measurements.
Oh wait, you have a computer model for that. Please continue while I stick my fingers in my ears and yell obscenities for unrelated reasons (sorry, it’s a programmer thing).
No need to apologize!
We understand!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
(If it weren’t that my two German Shepherds take EVERY-thing to heart and make it deeply personal, I would, too!)
You’ll be surprised to learn that sea level could be determined by planetary orbits …
A plot of the scalar sum of the angular momentum of the Sun and all the planets is shown here.
In the above linked website that plot is derived solely from planetary orbits. There is a very strong correlation between world temperature data and the 934-year and superimposed 60-year cycles in this plot. I postulate that magnetic fields from the planets affect the Sun and cosmic ray intensities, and the latter can affect cloud formation and thus climate on Earth.
The whole debate lies firmly within the science of physics in which I am well versed. Most people don’t understand thermodynamics, let alone radiative heat transfers. I have written about the latter in my paper “Radiated Energy and the Second Law of Thermodynamics” published on several websites in March 2012 and easily found with Google. That paper demolishes the false conjecture by James Hansen that back radiation can be added to solar radiation when calculating surface temperatures using the Stefan Boltzmann equation. All it can do is slow that portion of surface cooling which is itself by radiation, whilst having no effect on most of the cooling, which is not by radiation.
But the more important issue is the physics (based on the Second Law of Thermodynamics) which does explain all temperature data in tropospheres, surfaces, crusts, mantles and cores of all planets and satellite moons, and also explains the required energy flows to maintain the existing temperatures. Very, very few are aware of this physics, yet it is valid and correctly derived from the laws of physics which have stood the test of time.
Unless we attack the false physics in the greenhouse conjecture and present valid physics that does gel with reality, we don’t have a hope of quashing the hoax.
I believe we can present the correct physics, and such is in my book “Why It’s Not Carbon Dioxide After All” available from Amazon. If we don’t satisfy the world that the physics in the GH conjecture is false, and that other correct physics does explain everything, then there will be more of the same when the 60 year cycle rises again between about 2028 and 2059.
Hopefully Australia can lead the world, for I believe there could be a class-action sponsored by major companies against the Government for all the costs which such companies incur because of the false claims regarding carbon dioxide. If the Government lost such a case they would be forced to act and take notice of the correct science, and it would get global attention. I am confident that I could defeat any scientist the Government might use as a witness in such a case. Many of you will know that I have argued with hundreds on climate blogs and never been proven wrong regarding the content of my book. I’ve even offered $5,000 if proven wrong.
So, if anyone has any suggestions, or knows someone in an Australian law firm who may wish to take this on, let me know.
Hey, Anthony, would you look who came to dinner? lol … It’s….. Mister Cotton!
You need to stay off substances.
I suggest you all google Sir Harry Flashman. If you have not read the books, please do so. Witty stuff.
“”Mike Bromley the Kurd
January 14, 2015 at 2:14 pm
Funny how she hastily mumbles something about tide gauges being along coastlines, then runs away….from the obvious fact that if sea level rise were to become a problem, it would be along those same coastlines…””
She probably reckons that if the sea level in the Ocean rises far enough it will come further up the sides of the ships and eventually pour in and sink them…….
lol. (GRIN — no grin) You’re right. Mm, hm. She worked it all out in the bathtub with a model.
Obscene. Evil. This has nothing to do with global warming; the enemy is truth.
Complete NOAA analysis of all available data from 2005 to 2012 shows 1 mm per year.
http://hockeyschtick.blogspot.com/2012/12/noaa-2012-report-finds-sea-levels.html
has link to NOAA paper published in 2012.
Reading the full paper shows SLR from 2005 to 2012 measured by GRACE and JASON satellites at 1 mm per year. The amount of error in the analysis is about +/- 1 mm per year.
Plenty of photos from 19th century of the Statue of Liberty or foundations of the Brooklyn bridge. Compare those photos with the same view today and I can see no SLR. Even if the average SLR were 2 mm per year, the total SLR in the last 150 years amounts to 300 mm. Thats 1 foot. Tides in NY harbor have a typical full range of 5 feet on any given day. I doubt anyone looking at NY harbor will notice.
Great point, bw.
There are far more damaging storms on the horizon — Social Security, Public Pensions, Medicare, Medicaid, College Loan Default, Spiralling National Debt, etc. These events are real, not modeled, and unavoidable. They will impact future generations far more than a few millimeters of sea level rise.
“There are far more damaging storms on the horizon ”
Like O’s third term?
Martial law is the trump card, and who are his pals? Just sayin’
Paul January 14, 2015 at 5:13 pm
“There are far more damaging storms on the horizon ”
Like O’s third term?
Martial law is the trump card, and who are his pals? Just sayin’
—
I never mentioned any of those things. Hyperbole much? Ridiculous? Strawman?
I never mentioned Obama, his pals, or an Obama third therm.
You are delusional.
I take it you’re unaware of this event:
“Both Liberty and Ellis Islands were largely submerged by the storm surge from Hurricane Sandy, which made landfall on the evening of October 28, 2012. Liberty Island reopened on July 4, 2013. The Ellis Island Immigration Museum reopened on October 28, 2013, although it remains a work in progress. Elevator access is available to the Great Hall on the second floor and the exhibit spaces on the third floor. Because of the storm, most of the museum collection is currently stored in a climate-controlled facility in Maryland.”
http://www.nps.gov/stli/after-hurricane-sandy.htm
No secret that NYC harbor and area are subsiding, Phil. Have been ever since when. And so are we to be alarmed about sea level rise because of this?
Or perhaps you mean that we should be alarmed over tropical storms.
Please clarify.
Highly interesting. In 2008 Chao, Yu, and Li reported in Science (April 11th) that sea level rise had been linear for the previous 80 years and the slope of the rise was 2.46 millimeters per year. Their value was corrected for water held in storage by all reservoirs built since 1900. I of course sent an article in correcting Gore’s 20 foot rise prediction, both to Science and to Nature, and got thrown out without even a pretense at peer review. You report an overall trend of 3.0 +/- 0.04 millimeters a year which is very close to the value these guys reported in 2008, seven years ago. I am not sure how much difference correction for water held in storage would amount to. But as I said then, something that has been linear for 80 years is not about to change anytime soon.And that is basically what these data show.
Arno, the Colorado/ NOAA number 3.1 contains a 0.3 GIA model adjustment. The actual NOAA shoreline rise is 2.8+/- 0.4. In other words, agreement with you and your cited paper within error of estimate.
Interesting that the Hay paper takes no account of GIA. It boggles the mind that they think a rough and sloppy estimate can be taken as gospel while actual measurements are dismissed.
Claims of sea level rise acceleration in the last 30 years are simply not supported by actual empirical data and thus the product of ideologically driven climate alarmism.
http://wattsupwiththat.com/2014/07/16/latest-noaa-mean-sea-level-trend-data-through-2013-confirms-lack-of-sea-level-rise-acceleration-2/
Somehow I missed this one when it came out. Great post!
“1. Respected scientists publish peer-reviewed paper(s) following years of pain-staking fieldwork, research and analysis.”
And as Ivor Ward alluded to, telling all other scientists that have spent hundreds if not thousands of years on the same subject that they are wrong while your respected scientists were using either incredibly naïve or dishonest logic||
Flashman – No sir. You sir are not a Sir, just a troll.
Believe, models, IPCC, Harvard….it has to be right, right???😨😱😰😓😓😓
“1. Respected scientists publish peer-reviewed paper(s) following years of pain-staking fieldwork, research and analysis.”
And as Ivor Ward alluded to, telling all other scientists that have spent hundreds if not thousands of years on the same subject that they are wrong while your respected scientists were using either incredibly naïve or dishonest logic||
Flashman – No sir. You sir are not a Sir, just a troll.
Clearly another case of don’t believe your lying eyes; instead you should believe the data we derived from our models and estimates even though they don’t agree with what your lying eyes are telling you.
Seeing as that NOAA has cooled the past, the oceans can only have reacted by contracting … I think I’ve made the eureka discovery of the new fabricated lower sea levels.
Perhaps this story could use a little inspection from anyone with some time on their hands. http://news.psu.edu/story/340288/2015/01/12/research/nasa-awards-30m-grant-penn-state-help-answer-climate-questions
Until a real scientist comes along…
I just read the story you linked to, Mr. Haldane. Thank you for sharing (ugh). For me, it boiled down to this:
“Methane, … is the second largest contributor to anthropogenic climate change.
*** “… The gas and oil boom in the U.S. may be increasing methane emissions. Our airborne measurements will improve quantification of these sources.”
Conclusion:
Envirostalin1sts “investing” $30 million of money they don’t have
(National Debt currently around $18 trillion)
to come up with an excuse to tax
(for a return of far more than $30 million)
those who risk their own capital to make a profit
(this time, in petroleum production).
*********************
On the face of it, given its underlying premise, its raison d’ etre,is an unsupported assumption that human CO2 emissions can do anything to alter the climate zones of the earth, it is a bogus “study”
which IGNORES DATA: per SCIAMACHY satellites, high CO2 values, i.e., big CO2 sources are not in industrialized nor highly populated regions (they are in the Amazon basin, tropical Africa, and SE Asia).
You had me at “Envirostalin1sts”.
Nils Axel Morner put out a paper dated July 4, 2013 about sea level measurements. Part of the abstract says “The methodology applied and the views claimed by the IPCC are challenged. For the last 40-50 years strong observational facts indicate virtually stable sea level conditions. ”
And “Best estimates for future sea level changes up to the year 2100 are in the range of +5 cm ±15 cm.”
http://multi-science.metapress.com/content/q7j3kk0128292225/?p=1e6aa26ee2a94c7a9a6d9a3939896d95&pi=13
I’ve been going to the same beach for 40 years, they say sea level has risen almost 4 inches over that time, but I don’t notice any difference. You could just as easily convince me sea level is dropping from what I’ve seen.
A major reason for the sea level rise, that this study seems to have overlooked, might be runoff from a new swine farming regulation requiring porcine showers be installed in all facilities.
Add those showers to the new regulations covering chickens and I see why my bacon and eggs breakfast is costing more. 🙂
[No, bacon costs more because are now required to get regular showers … Which also requires more water. .mod]
Ah! Hogwash.
Your copy of the abstract starts out with the sentence “Estimating and accounting for twentieth-century global mean sealevel (GMSL) rise is critical to characterizing current and future human-induced sea-level change.” The only human induced sea-level change is the tonnage of shipping that we float on the ocean. While global warming should cause sea-level change that has nothing to do with mankind.
A simple plot of temperature and CO2 concentration against time at a monthly or finer scale reveals an obvious annual cyclic variation in both variables. Linear regression applied to incremental changes in both temperature and CO2 concentration does not produce a significant correlation but cross-correlation reveals that the CO2 concentration lags the temperature by a few months. This is the well known seasonal life cycle which produces a major part of our food supply.
Temperature rises in Spring and Summer causing life forms to flourish with an accompanying take up of CO2, i.e. concentration decreases. Then in Autumn and Winter the temperature falls causing the demise of the life forms and a corresponding release of CO2 leading to an increase in concentration. This is the complete reverse of the proposition by the IPCC that increased CO2 concentration causes temperature to rise. Here the annual rise and fall of the temperature causes a fall and then a rise in the CO2 concentration.
Take away the season variations and one is left with a simple slope for CO2 which slope gradually increases with time. The current rate of increase of CO2 concentration is roughly four times the rate when measurement began yet the temperature has remained stable for the past 18 years. This fact does not get a mention by the IPCC.
Apply linear regression to the annual differences in CO2 concentration and the average temperature for those periods and there is a statistically significant correlation. A check of the annual increments for each of these variables also provides a statistically significant correlation. Clearly temperature sets the rate of change of CO2 which possibly emanates from perennial life forms and sea-water.
Conclusion: Temperature drives the atmospheric concentration of CO2. If there is a so-called greenhouse effect, it is too small to be detected in current measurements and is not likely to influence sea-level.
I found the entire post totally confusing.
There was no reference in the post that I could see where the first set of graphs was discussed….that set clearly shows the rate of rise decreasing”..but no one discusses that.
Then the two discussions go on a convoluted circular argument and both are saying that the rate of rise is increasing….
This is one of the most un satisfying posts I have read on your web site. I normally find the stuff fairly readable…….not this time. It doesmnt make any point.
Holy mackerel! Tuvalu will be completely underwater in only 4000 years! http://www.bom.gov.au/ntc/IDO70056/IDO70056SLI.pdf
Is Inhofe going to get rid of these phonies ?
There are roughly 540,000 miles of coastline right now.
That’s 870,000,000 meters. (More or less.)
Engineering Geology – Page 143 – Google Books Result
https://books.google.com/books?isbn=0080469523
For an “average” coastline, beach slope – which IS after all, what they are worried about, right? is going to vary as shown above by type of sand or gravel. It is, after all, that actual “land” at the ocean front that is being covered right now as “sea level rises” and causes international catastrophes and death to millions, right? ( Well, at least more deaths than artificially restricting energy worldwide occuring to their theories.) The rest – where FL or Pakistan or India gets flooded is only exaggerations and propaganda.
So, If sea level goes “up” by 1.0 meter, then each section of beach at each different slope increases the volume of the ocean total, right? Assume for arguments sake, that each type of shore line above is 1/7 of the total.
Then, if a fine sand beach has a 2 deg slope, then a 1.0 meter rise in sea level = 1.0 m/tan(2 deg) = 28.6 meters of “new” ocean area that had to be flooded by the “new” water.
new “volume” of water that was required for this part of total shoreline =
1/2 x L_new_shore x ht x W_new_shore = 1/2 x 1/7 of 870 x 10^6 m x 28.6 m x 1 m = 1777 x 10^6 m^3
Repeat for the remaining 124 x 10^6 meters of shoreline for each of the other slopes.
Hmmmn. 3,916 x 10^6 “extra” cubic meters of “extra” ocean to fill up if the oceans rise 1.0 meter = 3.916 x 10^9 m^3
Greenland is supposedly losing 200 cubic kilometers per year.
200 x 10^3 x 10^3 x 10^3 meters = 2.0 x10^11 m^3 /year
Nope, not enough to reduce the sea level rise sufficiently. Good to think about though, isn’t it?
You made a good start. The stage vs. storage relationship in the ocean basin is called the “hypsographic curve” which can be looked up. Note that the dry coastline granular material contains interstitial pores which must be filled or saturated before a rise manifests itself. The porosity issue was investigated some years ago in “Sea-Level Change”, Studies in Geophysics, National Research Council, 1990. Table 2 on Page 12 gives pore space and sea-level equivalent. For coastal plains and shelves, the pore space is equivalent to 1.7 meters. I interpret that to be 1.7 meters of sea level rise equivalent drawn into filling the empty pore space.
It is something fishy!!! Some areas rising, some areas show falling and majority of the areas no change. Also, localized human action including extension of urbanization influencing the sea level change. Drilling for oil, gas & water, natural disasters like Earthquakes & Volcanoes in the sea, tectonic movement of seabed, etc. Without looking in to all these aspects showing a curve with beautiful increase is unrealistic. Also, lumping all these in to one is not scientifically valid.
Dr. S. Jeevananda Reddy
The local shore elevation in several areas has been substantially RAISED by re-injecting ground water below the shore. Baytown TX, for example, raised several areas by as much as 6-8 feet when those neighborhoods were flooded out after the ground water was pumped out. Japan stopped completely local subsidence by controlling ground water pumping, as did Louisiana and FL and parts of the Philippines and Taiwan.
So, pump back in seawater below the threatened areas. But only in the threatened areas where underground/underwater conditions are right.