Sea Level Data In Monthly Format
Guest post by Bob Tisdale
In this post I have also provided comparisons to scaled NINO3.4 SST anomalies. As could be expected, some of the rises and falls are related to ENSO events. The step changes also appear to be direct responses to El Nino events. I am not, however, implying that Sea Level variability is only impacted by ENSO.GLOBAL SEA LEVEL
The monthly Global Sea Level data from December 1992 to March 2009 is illustrated in Figure 1. The late 1995 spike in the sea level data stands out similarly to the way the 1997/98 El Nino stands out in global temperature data.
http://i31.tinypic.com/op5nw1.png
Figure 1
Figure 2 compares Global Sea Level to scaled NINO3.4 SST anomalies. The peak in late 2005 is not directly related to an El Nino. The impacts of the 1997/98 and the 2002/03 El Nino events, however, can be seen in the Global Sea Level data.
http://i31.tinypic.com/2mrgo5x.png
Figure 2
MONTHLY SEA LEVEL FOR THE ATLANTIC, INDIAN, AND PACIFIC OCEANS
As preliminary notes, the annual variability in the Atlantic and Indian Ocean Sea Level data can be clearly seen in the monthly data. The Pacific data is noisier, which masks an annual signal.
Note how the smoothed Atlantic Sea Level data, Figure 3, appears to rise in steps. The first step is in 1995. This should be a rebound from the Mount Pinatubo aerosol effects.
http://i27.tinypic.com/zs4m0.png
Figure 3
The scaled NINO3.4 SST anomaly data has been added in Figure 4. The smoothed Atlantic Sea Level data rises again in 1997, which should be a response to the 1997/98 El Nino. Are the rises in 2003 and 2005 also responses to the 2003/04 and 2004/05 El Nino events?
http://i32.tinypic.com/t8nrch.png
Figure 4
The raw and smoothed Indian Ocean Sea Level data, Figure 5, show a major step change in 1998 and a curious increase in trend in 2004.
http://i31.tinypic.com/25qzrdi.png
Figure 5
The 1998 upward step in the smoothed Indian Ocean Sea Level data appears to be a lagged response to the 1997/98 El Nino. Refer to Figure 6. The 2004 change in trend does not appear to be ENSO related. Was there a shift in Indian Ocean cloud cover in 2004?
http://i31.tinypic.com/1415glt.png
Figure 6
Following the significant increase from 1998 to 2002, the Pacific Ocean Sea Level, Figure 7, has been relatively flat since 2002. The rise in Pacific Sea Level slowed after 2002, and Pacific Sea Level has declined since 2006.
http://i31.tinypic.com/hsta3q.png
Figure 7
In the comparison with NINO3.4 SST anomalies, Figure 8, note how the Pacific Ocean Sea Level surged upward in mid-1996, one year before the 1997/98 El Nino. Does this indicate that there was a sudden rise in ocean heat content in the year leading up to that El Nino? Does this confirm the findings in my post āDid A Decrease In Total Cloud Amount Fuel The 1997/98 El Nino?ā It does seem to show that the 1997/98 El Nino was fueled by a short-term change (one year) in the ocean heat content of the Pacific.
http://i28.tinypic.com/2enn4lk.png
Figure 8
ATLANTIC, INDIAN, AND PACIFIC OCEAN COMPARISONS
Figure 9 is a comparison of Sea Levels for the Atlantic, Indian, and Pacific Oceans. Note how one dataset always appears to be out of phase with the variations of the other two. Rarely do the sea levels of all three oceans rise or fall in unison.
http://i30.tinypic.com/2wh2k9f.png
Figure 9
The SST anomalies for the Atlantic, Indian, and Pacific Oceans are illustrated in Figure 10. There are significant differences between the SST and Sea Level curves. (I canāt see any reason to compare the individual ocean sea level and SST data.)
http://i32.tinypic.com/2gxl5ja.png
Figure 10
SOURCE
Sea Level data is available through the University of Colorado at Boulder webpage:http://sealevel.colorado.edu/index.php
Specifically:http://sealevel.colorado.edu/results.php
Very interesting work, thank you!
How many homes/properties have been reported damaged/destroyed with rising sea levels as direct cause in the past 20 years?
I know that some areas in the world for varying reasons are very prone to flooding (Bangladesh for example), but is it very common that property is damaged from rising sea levels specifically?
Heated water expands. Cooled water contracts. Sea level appears to be a lagging indicator of global temperature trends.
Is there really anything other than that going on here?
A question for Bob-any idea why sea level apparently continued to rise after 1998 but sea surface temps didn’t? Apart from a large trend the data seem to behave similar to sea surface temps. Does that mean that a rather large forcing is being applied to the system but has lead to only a very minimal change in temps as yet? if so that would seem to me to be a very important result!
Patrik (09:11:16) : I doubt that 60 something millimeters of sea level rise damaged anyone’s property.
Hurricane Storm surges on the other hand, have done huge damage in the last twenty years, and are several orders of magnitude greater and come in a matter of hours, rather than centuries or millennia.
And in case your worried about THAT increasing from AGW, your concern is misplaced. There is an issue of increasing storm damages, but entirely from rising coastal population and inflation (mostly the former, surprisingly).
Very timely, Mr. Tisdale. Fascinating work, well done!
Thursday and Friday of this week (July 23 and 24) are expected to show coastal flooding along Southern California beaches, per the National Weather Service.
The cause is astronomical high tide coupled with some 4 to 7 foot (roughly 2 meter) waves that originated in the central South Pacific. see http://www.wrh.noaa.gov/lox/
I expect the AGW crowd will make much of this, if any flooding actually occurs.
a link to the Coastal Flood statement:
http://forecast.weather.gov/wwamap/wwatxtget.php?cwa=lox&wwa=coastal%20flood%20statement
Thanks Bob,
Interesting work.
If you have time, please plot seasonal (monthly) sea level vs the seasonal CO2 sawtooth data, and let us know what you find.
Suggest you use Mauna Loa CO2 and Pacific Ocean.
Regards, Allan
That’s an interesting observation about the sea level changes in the three basins being in phase for only two of them at a time. The time series is too short to deduce a sequence pattern, though. By eye there doesn’t seem to be a relationship to the SST anomaly patterns. Any speculations?
RE: ” wws (09:11:35) :
Heated water expands. Cooled water contracts. Sea level appears to be a lagging indicator of global temperature trends.
Is there really anything other than that going on here?
=================
There is also the long trailing edge of the general rise following the great melt 10K years ago. There is still water in high latitude bogs / muskeg, from that event, slowly filtering into river systems or directly into ocean basins as ground water.
The science is in. On Teevee they showed this.
Actually it was explicitely presented at the whitehouse a few weeks ago.
timetochooseagain: You asked, “any idea why sea level apparently continued to rise after 1998 but sea surface temps didnāt?”
There is much more to sea level than SST anomalies. Sea level captures temperature and salinity variations for the entire column of water where the SST data only captures the surface temperature. Sea level also captures water exchanges from glaciers, and it is also impacted by post-galacial rebound.
With regards to the last item, the AVISO website will allow you to create graphs of Sea Level with or without Glacial Isostatic Adjustment. That adjustment represents about 10% of the trend since 1992.
http://www.aviso.oceanobs.com/en/news/ocean-indicators/mean-sea-level/altimetry-data-and-images/index.html
That image of Florida reminds me of the cartoon … uh, I mean “simulation”, in Al Gore’s movie, where Florida is inundated from 20′ sea-level rise by the end of the 21st century. Which, at the time, reminded me of the old Anacin commercial with the animated arrow showing how Anacin “gets to your headache” 40% faster than Bufferin. The guy in the white lab coat, clipboard and pointer made it all very “authoritative”.
Both used the same “methodology” to prove a point.
I think you have correlation so far, but not causality.
The alternative explanation would be that the ENSO cycle is driven primarily by internal dynamics, and when you get an El Nino it clears up the cloud cover over the equatorial pacific, which increases heat absorption by the pacific and increases sea level rise and OHC. There could obviously be coupled positive feedback effects (ENSO -> cloud cover -> SSTs -> ENSO) that makes distinguishing cause and effect difficult and would produce the correlation.
Why can we regard the ocean basin as being a constant volume? There are plates pulling apart, plates subducting, volcanic islands growing (do they lower the sea-floor locally?), silt inflow &c.
Are they all ignorable?
The Atlantic, Pacific and Indian Oceans are of very different sizes. Can you do a weighted average rise of the three?
It looks like something happened with earths albedo the years before the 97/98 El Nino. There where a rapid decrese of earths albedo 2-3 years before 97/98 El Nino event and it stayed low until 2002 and then seemed to rapidly increase again.
See http://www.bbso.njit.edu/science_may28.html
With a 5 year smoothing on RSS data there is a step increase in temperature that follows this rapid change in albedo.
Whe know the sealevel is rising slow trough the century. It hassen’t speed up scince co2 levels rise. But if it doese no worry’s It won’t happen verry rapid. My hous is -1,25 Meters below sealevel. I can perfectly trust our water system.
Everything I know about what things can affect sea level is summed up here:
” ”
That being said, did the seafloor uplift during the 2004-12 Indian Ocean earthquake have any measurable long term affect on sea level, local or otherwise?
O/T a little but not really.I live in the northern foothills of N.C.. Last night on the local weather ,Van Denton at fox8,showed ther last 3 summers comparisons on tems.In 2007 he showed we had already had 63 days above 90 in Greensboro N.C. last summer os of july 21st we had had 36 days.This year there has been ONLY 6 as of july21st which is the mid piont of summer.Like Isaid I live in the northern foothills of N.C. and we have had maybe 3 or 4 tops.It truly has been like spring all summer so far.My wife and Iwere on the Blue Ridge PArkway last weekend near Mayberry Mill and the temps got into the 40’s on sat night.People were in coast which is odd to me in july. My point is the cool weather isn’t just in the northeast this summer as the media or weather channel would have you believe.Right now it is 79 degrees outside and it will probably get to low 80’s which is what we have had most of the summer or cooler .I just checked accuweather for next 10 days and it more of the same 70′ and 80’s.
Very interesting data. If nothing else, everyone is learning about the earth and sun everyday with regards to the AGW studies.
Has someone did a study on just the increase of CO2 due to population increases and exhaling of CO2? Maybe some Government will release the Swine Flu or something to reduce the population. Oh, did I say that? Ouch!
Jerker Andersson (10:23:52) : “It looks like something happened with earth’s albedo the years before the 97/98 El Nino….”
Plankton?
I’m thinking the circle of the Earth has a certain radius.
The temperatures a few thousandths of a radius up into the atmosphere are very, very cold, and the temperatures a few thousandths of a radius down into the depths are very, very hot.
I’m also thinking the Earth rotates about its axis once a day, revolves around the Sun once a year, and the Moon revolves around the Earth about once a month, thereby causing huge, and variable, energy transfer — at least radiative and gravitational.
I’m also thinking that way down deep in the Earth are currents of molten material at very high temperatures, conducting huge, and variable, energy up out of those depths.
I’ve read about satellite measurements of land areas rising and sinking. And I’m figuring the sea-bottom must also have a similar sort of variable, flexing motion, though maybe it’s constrained a bit by pressure from the sea weight.
And then I read of sea-levels rising a few billionths of an Earth’s radius, maybe a bit more, maybe a bit less.
To me, that any global warming, cooling, rising, or sinking is so incredibly constant over centuries or millennia is simply astounding.
Also. The Sun (about a million Earths in size) belches out its huge energy a mere 24000 Earth radii away.
That we survive in the relative width of a human hair on an 8-inch Earth is (to me) even more astounding.
In ages past we learned about the virtue of humility. We also learned that political/philosophical/religious arrogance could result in staggering misery, suffering, and the destruction of life and property.
What we never learned — or even dreamed of — was that the arrogance of the supposed intelligentsia would cost premeditated, self-extorted trillions. Not to mention the death of science, and truth as once known.
Not just temperature changes sea level. There is also the amount of water vapor in the atmosphere, amount of water exchange with that on land – rivers, lakes, snow, ice; gravity. And don’t forget that the oceans are just a giant bath tub of water sloshing around a very complex shape.
AH, forgot. Also, tectonic plate and land mass movements, verticallly and horizontally.
Lamont: You wrote, “The alternative explanation would be that the ENSO cycle is driven primarily by internal dynamics, and when you get an El Nino it clears up the cloud cover over the equatorial pacific, which increases heat absorption by the pacific and increases sea level rise and OHC.”
The cloud cover/cloud amount follows the warm water. During La Nina and ENSO neutral periods, the cloud cover and precipitation are highest over the Pacific Warm Pool. During El Nino events, when the warm water sloshes east, the clouds and precipitation follow. This causes significant decreases in “normal” total cloud amount over the Pacific Warm Pool, which would help “recharge” the warm water there. The warm water also sloshes back toward the Pacific Warm Pool during the subsequent La Nina. Some of the water that had travelled east during the El Nino is redistributed around the surface of the Western Pacific and Eastern Indian Oceans by surface currents. This causes step changes in SST. But I havenāt studied how it impacts sea level or OHC.
Regards
Steven Hill wrote: Has someone did a study on just the increase of CO2 due to population increases and exhaling of CO2? Maybe some Government will release the Swine Flu or something to reduce the population. Oh, did I say that? Ouch!
There is a study on the impact of human heat emissions here:
http://www.ltu.se/forskning/1.16009?l=en&pureId=2090518&pureFamily=dk.atira.pure.families.publication.shared.model.Publication
Essentially the conclusion is that heat of all sources emitted by humans account for around 75% of the recorded heating blamed on AGW, but not through CO2 emissions. These are only recorded as having caused around 25%.
Steven Hill:
You forgot to mention all the carbon-dioxide being released from fizzy drinks bottles like Coca-Cola. That’s what’s doing it! Coca-Cola is destroying the planet!
Don’t worry dear believers, you know that many of your prophets have beach houses, so you won’ t drown at least in the near future…believe them!
Bob, the ’98 el nino released a huge amount of heat from the oceans into the atmosphere, which can’t have had an instant effect on glaciers. How come the sea lvel jumped upwards and back down around 1998?
First thanks for the data and analysis —
How an engineer looks at sea level:
1. How low was the water level during the last ice age?
2. How high has it risen since the last ice age thawed out?
That would be about 100 meters or so rise since the end of the last ice age.
OK so what do we have going on now? Engineer’s answer: mm of change, hmmm — Margin of error.
By the chart of and depth’s in SW Florida, I am in deep water soon. Better pack the boat now just in case. I always liked this song by Johnny Cash http://www.youtube.com/watch?v=91OIaPRrDts
Just to answer my own question, solar cycle 23 was on the upramp which would have raised levels, and the release of heat dropped them again. They soon started upwards again as ss23 was still waxing.
PSU-EMS-Alum (10:37:28) :
That being said, did the seafloor uplift during the 2004-12 Indian Ocean earthquake have any measurable long term affect on sea level, local or otherwise?
I wondered the same myself.
Have the world’s Navys been contributing much data relating to the seas? Given the usefulness of thermoclines for submarine/antisubmarine warfare I’m assuming they may have amassed a pile of potentially useful historical data. Plus whether they’ve released ice thickness data from sub-polar work, or if that’s considered too sensitive.
All the fuss over a range of a few inches. That’s it.
Hurry, sell your beachfront property, you must act quickly. I can see the handwriting on the warming already. KilGore was here.
Now, why would they be deeping the Suez and Panama Canals? If sea levels are rising, who cares about the approaches.
If history is any guide, the rise is slow and the fall is abrupt.
Why is that? When the ice melts, the land rises up as the weight is lifted. Higher land where ice abounds gathers more. Held in check.
My best guess is that when the climate turns colder, the land massses fall under the weight far more grudgingly. The volcanoes might be the pressure relief valve that allow this. Geologic study needed.
timetochooseagain (09:21:02)>>
Oh, I’m not worried. I live on a hill. š
No, really, I’m not worried at all. I was just thinking that if sea levels are rising there certainly would be some amount of reporting about damaged stuff from around the world, but I hear nothing about this in media. I find that strange.
WRT plate tectonics, NZ had its largest earthquake for almost 80 years just a week ago, magnitude 7.8 and equal to the devastating 1931 quake that effectively devastated Napier.
No injuries, relatively little damage, but the southern South Island is now around a foot closer to Australia. The area around the epicentre is also about three feet higher. Haven’t noticed any sea level change, though. Nor any reduction in airfares.
Off topic: Seattle area readers may be interested in attending this global warming conference tomorrow. This was the first I had heard of the event, though I read several Washington state news sites everyday. Imagine that, the mainstream media ignoring skeptics!
http://www.washingtonpolicy.org/events/environment_2009.html
I won’t be holding my breath waiting for the Seattle Times to report on this event in Friday’s edition.
Not too strange that they can’t report such a tiny change doing damage, but that doesn’t stop them from trying, in my experience.
You’ve all forgotten the effect of new supertankers and container ships displacing hugh volumes of water, ergo the sea level rises. Remove all the ships from the sea and problem solved;-)
Lots of nice data Bob; not so easy to figure the whys and wherefores.
Everybody understands there is a simple thermal expansion component. Somewhere I remember reading that in fact mid ocean temperatures were inferred from satellite radar measurements of the sea surface level, and then computing back from the assumed expansion. I remember reading it, but haven’t a clue where, and maybe it’s an urban legend. And if expansion is only part of the equation, then that wouldn’t seem to be a sound methodology; certainly highly indirect; about as proxy as one could imagine.
But if one makes a simplifying assumption; that the coefficient of expansion is a constant, and doesn’t vary with temperature or salinity (fat chance); then one can make a good case for arguing that the sea level rise (due to expansion) simply depends on the total “heat” energy increment.
Assuming (and we know what assume means), constant coefficient of expansion, and constant specific heat, independent of T and S (salinity), then a given amount of “heat” energy can warm a long column of water by a small delta T, or a shorter column of water, by a larger delta T, and even the stick in the sand approach, will show exactly the same rise in height of that column for a fixed increment of thermal energy.
Now given that we are not talking about a huge delta temperature range, in the tropical regions; those assumptions of parameter constancy, are probably reasonable.
When you get to the polar seas, where the temperatures are zero C or sub zero, then the assumption of a constant temperature coefficient of expansion is a bit more frivolous, since salt water freezes at the point of maximum density around -2.5 deg c for 2.47% salinity, and typical ocean salinity is 3.5%, and may be considerably larger near growing ice, due to the salt exclusion from the ice.
But in any case, in those polar seas, if we actually do have global warming and ice loss, then the polar seas would actually be cooling from giving up the latent heat to melt the ice; so the polar sea level would be falling; and in the case of the Arctic Ocean, has in fact been measured to be falling (over ten years) by 2 mm per year (as of mid 2006).
But in tropical oceans, an assumption of a fixed sea level rise for a given heat energy addition; regardless of energy distribution; would be reasonable.
Looking at your graphs with the SSTs, my eye (I have simply awful eyesight), says if anything the SSTs have fallen slightly; so I don’t see a connection bewteen SSTs and sea level rise. If that is a totally wrong observation; I’d be happy to hear that. Of course I am not looking for any thermal delays either. Does it make sense to you, that since total sea level rise would seem to be independent of the actual thermal energy distributiuon with depth, the expansion would not be delayed (much). You dump a lot of “heat” into a thin surface layer, and it expands greatly, and promptly, by a certain amount. As the energy disperses to deeper waters (taking its time), you get a lesser temperature rise, of a greater column of water; but the total vertical expansion remains constant.
So i think it is a mistake to expect any significant delay of sea level rise due to just “heat” energy input.
Now for water mass increases, due to land runoff from whatever mechanisms; I would expect a time delay.
Does any of this make any sense to you Bob ??
George
Patrik (12:31:09) :
Outstanding, Patrick. You just hit the 4d finsish nail on the head heard round the world.
Sea level RISE is a gross exaggeration and misleading.
Sea level CREEP would be far more fitting a description.
Another contributor to raising sea level must be the estimated 800,000 ton “dustball” reported in the UK Daily Telegraph today. (http://www.telegraph.co.uk/news/worldnews/asia/china/5877583/Giant-Chinese-dustball-circles-the-Earth.html).
“A group of Chinese and Japanese scientists claimed that the dustball, which weighed 800,000 tons, was kicked up during a storm in 2007 in the Taklamakan desert.
The desert, which is roughly the size of France, lies in China’s far-Western Xinjiang province, and is fringed by mountains on three sides, including the Pamir mountains on the border with Afghanistan and the Karakoram range, an extension of the Himalayas.
The dust ball was formed when a wind storm ripped across the desert, kicking up the dust, and trapping it against the mountains of the Tibetan plateau.
The scientists said the dust was forced higher and higher into the air, until it reached an altitude of around 16,250ft. A warm convection flow then lofted it further to between 26,000 ft and 32,500 ft, well above cloud level.
The dust was then trapped in the polar jetstream, a fast-flowing air current that lies just under the stratosphere, and began its “journey around the world” according to the Nature Geoscience journal.
The team of scientists tracked the progress of the cloud using tools aboard the Nasa observation satellite Calypso. After 13 days, the plume of dust passed back over the Taklamakan desert, having completed a full circuit of the globe. The scientists noted that even after such a long journey, the dust remained “tightly confined in latitude”.
It only fell back down to earth after crossing half the globe again when the cloud encountered a ridge of low pressure and fell into the Pacific ocean. Some of the dust managed to reach North America and then fall into the Atlantic.
“The Taklamakan desert is a major source of dust transported and deposited around the globe,” the scientists noted, adding that dust from the desert has turned up in ice cores in Greenland and in the French Alps. They also suggested that micro-nutrients from the dust could have a beneficial effect on the oceans, helping to feed plankton. ”
OK – it’s probably not a particulary significant amount in terms of the total volume of the oceans, but it is the consequence of just one event. This does show that there must be a substantial amount of solids picked up from the land by weather events and deposited in the sea, over and above that carried into the sea by run-off….. and that’s without all the fat plankton boosting the volume
Bob,
To facilitate Nino phase-comparison’s, you might try:
A) differencing.
B) year-over-year differencing …which is equivalent to time-integrating (smoothing or summing) A at annual-bandwidth.
Also, don’t forget the long-term, stone-soup effect on the ocean from outer space detritus — a few tons a year isn’t much, but over the ages it adds an upward trend that we can’t directly measure in our short time span.
Choa et al in Science 11 apr 08 state that there is an essentially constant rise in sea levels of 2.46mm per year for the last 80 years once fresh water impoundment has been taken into account.
tallbloke: You wrote, “Bob, the ā98 el nino released a huge amount of heat from the oceans into the atmosphere, which canāt have had an instant effect on glaciers. How come the sea lvel jumped upwards and back down around 1998?”
Global TLT rose as a result of the 1997/98 El Nino and so did Global SST, including areas outside of the tropical Pacific.
Allan M R MacRae: You wrote, “If you have time, please plot seasonal (monthly) sea level vs the seasonal CO2 sawtooth data, and let us know what you find.”
Please provide a link to the specific CO2 dataset you’d like compared.
First July in Ky history that won’t have one single day in the 90’s. 67 right now with rain. 3rd straight day without AC for us.
Major Atlantic spikes lag major Pacific spikes by (on the order of) ~1 year. This is a new set of time-series for me — is this a well-know phase-lag that has been well-explained?
noaaprogrammer (14:14:43) : Also, don’t forget the water-bearing comets that add to our H2O inventory …
http://csep10.phys.utk.edu/astr161/lect/comets/smallcomets.html
Re water added to the oceans: don’t forget to add the water created by fossil fuel combustion — it is roughly 7 cubic miles of water, from 1900 through 2008. Not even a drop in the bucket.
wonder if this could be a factor?
Maybe Anthony wants to go on an Indian Ocean cruise?
http://www.weeklytimesnow.com.au/article/2009/07/21/94421_back-paddock.html
“July 21, 2009
THE accuracy of long range weather forecasts has been copping a bit of stick recently.
Farmers reckon they could do better by looking out the window. But they could aim their scorn at deep-sea fishermen, who aren’t helping.
Word from the Bureau of Meteorology is that quite often the buoys, which monitor sea temperatures in the Indian Ocean, which in turn have a big bearing on rain in Rupanyup, are being vandalised by fishing boats.
Apparently they see them as handy anchoring points or even for a bit of target practice.”
George E. Smith: You wrote, āSomewhere I remember reading that in fact mid ocean temperatures were inferred from satellite radar measurements of the sea surface level, and then computing back from the assumed expansion. I remember reading it, but havenāt a clue where, and maybe itās an urban legend.ā
Wikipedia gives a reasonable explanation of how satellites determine SST. It never mentions your legend:
http://en.wikipedia.org/wiki/Sea_surface_temperature
You wrote, āSo i think it is a mistake to expect any significant delay of sea level rise due to just āheatā energy input.ā
I would think that any lag (from ENSO or volcanic eruptions) would result from the time required to circulate the change via atmospheric and oceanic processes.
You wrote, āNow for water mass increases, due to land runoff from whatever mechanisms; I would expect a time delay.ā
Agreed.
Roger Sowell (15:52:06) :
“Re water added to the oceans: donāt forget to add the water created by fossil fuel combustion ā it is roughly 7 cubic miles of water, from 1900 through 2008. Not even a drop in the bucket.”
But what is that in mm of SL.
Paul Vaughn: You asked, “Major Atlantic spikes lag major Pacific spikes by (on the order of) ~1 year. This is a new set of time-series for me ā is this a well-know phase-lag that has been well-explained?”
I’ve never seen it discussed, but I don’t spend much time studying sea level.
Patrik (09:11:16) :
How many homes/properties have been reported damaged/destroyed with rising sea levels as direct cause in the past 20 years?
I know that some areas in the world for varying reasons are very prone to flooding (Bangladesh for example), but is it very common that property is damaged from rising sea levels specifically?
Patrik,
Properties destroyed by a storm surge or a tsunami? Yes
Properties destroyed by coastal erosion? Yes
Properties lost by sea level rise? Mention me a single specific example
Those examples advertised as caused by sea level rise (in this case another word for Global Warming) were caused by coastal erosion as independent research found out.
One example was in Alaska where the ice pack formed a buffer protecting some eskimo sheds (wooden houses) build on an unstable sand bank.
When the ice retreated for a short period of time due to wind and sea currents, the waves undermined the foundations causing the houses to tumble over.
Sea level rise was not the culprit.
It was coastal erosion, a process that is active for millions of years.
In Bangladesh there was a problem with two islands sinking below the water line.
Sea level rise was the cause it was stated.
But when the authorities dredged the river plane which was filled with sedimentation deposited by the river, o wonder, the islands appeared again.
Just answer this question:
If sea level rise would be a serious problem. Why would Al Gore buy a million dollar condo at the sea side?
Right, because it is not a problem.
At coastal area’s with beeches the high tides and the waves flush sand upon the beech causing the beaches to rise when ocean level rise.
The speed of this process, now reduced to almost zero, is slower than your toe nails grow.
In short: THERE IS NO PROBLEM
All scary stories are based on highly exaggerated models that do not match the real world conditions.
This is a nice read about the subject:
http://www.john-daly.com/
The Florida “scare” map gives me a chuckle. I am located on the central west coast about half way between Tampa Bay and Port Charlotte Harbor. I live about 1 mile inland from the Gulf and this map has me in blue. Umm, one slight problem though, the official elevation certificate for my house used for flood insurance has me at 15 feet above sea level. So either the map is a load of crap or sea levels will have to rise over 15 feet for this to be an accurate representation. I believe it is the former.
Bob:
Nice article. What links do you see, if any, between the changing sea level in the Indian Ocean and what is happening to the Cook Glacier on Kerguelen (see http://news.yahoo.com/s/afp/20090722/sc_afp/scienceclimatewarmingglacier )espcially given that the GISS data for Kerguelen gives no indication that the local air temperature has changed significantly – http://data.giss.nasa.gov/cgi-bin/gistemp/gistemp_station.py?id=143619980003&data_set=0&num_neighbors=1 .
ftp://ftp.cmdl.noaa.gov/ccg/co2/trends/co2_mm_mlo.txt
Thank you Bob.
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In response to:
Bob Tisdale (14:32:30) :
Allan M R MacRae: You wrote, āIf you have time, please plot seasonal (monthly) sea level vs the seasonal CO2 sawtooth data, and let us know what you find.ā
Please provide a link to the specific CO2 dataset youād like compared.
Jim, re what is the increase in mm of SL due to water added from fossil fuel combustion: negligible. Cannot measure it. Even if it were added all at one time.
Consider there is roughly 200 million cubic miles of ocean, and 7 cubic miles of fresh water from combustion were added over 100 years.
Someone may want to check that 200 million cubic miles, I did this with 8000 mile diameter sphere, 3 mile deep ocean on average, 70 percent of globe is ocean. Even if I’m off by 50 percent either way, the sea level increase is negligible.
Bernie: You asked, āWhat links do you see, if any, between the changing sea level in the Indian Ocean and what is happening to the Cook Glacier on Kerguelen (see http://news.yahoo.com/s/afp/20090722/sc_afp/scienceclimatewarmingglacier )espcially given that the GISS data for Kerguelen gives no indication that the local air temperature has changed significantly ā http://data.giss.nasa.gov/cgi-bin/gistemp/gistemp_station.py?id=143619980003&data_set=0&num_neighbors=1 .
Significance, one could say, is in the eye of the beholder. Is a 1 or 2 deg C rise enough to cause the glacier to recede?
But letās look at the long-term SST anomalies for the vicinity of Kerguelen.
http://i27.tinypic.com/kaqqyr.png
If we assume that variations in the land surface temperatures will mimic those of SST, and if we assume that glacier mass is impacted by surface temperature, itās pretty obvious why the researchers chose 1963 as the start date for their study. Would the mass of the glacier have increased from 1955 to 1963 as the temperatures dropped? And would a study that covered the period of 1963 to present have higher losses than a study that covered the period of 1955 to present?
Note that there was the big indian ocean earthquake in 2004 that caused the big tsunami. This may have increased the rate of tectonic subsidence related sea level rise and has nothing to do with global warming. Stands to reason with the release of plate tension that this would happen.
PSU-EMS-Alum (10:37:28) :
That being said, did the seafloor uplift during the 2004-12 Indian Ocean earthquake have any measurable long term affect on sea level, local or otherwise?
I can’t remember the exact figures but during this event, the plate which moved was about 1000km long by about 250km wide and was uplifted by about 10m. So yes – this would have raised sea level almost instantenaously by a small amount. Maybe someone else here would be able to estimate by how much this would have been.
There are lots of other geological factors which affect sea level – including the volume of the mid-oceanic ridges – these are always growing. Sediment input into the ocean basins also causes sea level rise. Localised subsidence causes localised sea level rise. Localised uplift causes localised sea level fall.
I’ll upload some pictures of rock outcrops which show the effects of rapid sea level rises on the rock record sometime soon.
Jim, Roger,
I get 0.056 mm – a “significant contribution from burning big oil” ? š
OMG! According to figures 4 & 9 the Indian Ocean is up 38mm (1.5 “) in the last 5 years — that equates to 2.5 FEET in a century. Abandon the Maldives, Abandon the Maldives!
WWS said “Heated water expands. Cooled water contracts. Sea level appears to be a lagging indicator of global temperature trends.”
Ummm, maybe land temperatures since the water takes longer to heat up, but that’s not the same as Global temperature. How could anyone ever possibly come up with an average temperature for the entire world. All this fudging of temperatures to get hundredths of degree changes is impossible — you cannot improve accuracy through averaging, or by using tools of less sensitivity, i.e. I believe thermometers in yonder olden days measured to the nearest degree Fahrenheit, and possibly could be eye-balled to a half a degree. So combining those data with 1/10 degree accuracy today cannot give us 1/100 degree accuracy!
JohnH: You wrote, āThe Atlantic, Pacific and Indian Oceans are of very different sizes. Can you do a weighted average rise of the three?ā
The area-weighted sea level graph of the Atlantic, Indian, and Pacific Oceans:
http://i29.tinypic.com/2a92kr5.png
I am neither a scientist nor a very good mathematician, but with the help of Google I reckon that, if sea levels were rising 1 mm a year, there would have to be an increase in the volume of water of 36.132 km3 a year or 36.132 trillion litres. Allowing for varying factors and knowing that , in spite of claims, the ice caps are not melting to any great extent; where on earth is all this water coming from.
At arm’s length this strikes me as being well withing the range of normal variability. There are a lot of possible explainations for the little bit of rise that we have seen. This is waaaay out of my field of knowledge, but it seems like a lot of things could combine to cause the very minor rise in sea levels. The top things that came to mind were (not in order) ;
Increased biomass in the oceans
Polar ice being blown into the Atlantic and rendered to water
Minor fluctuations in the hydrological cycle
Tectonics
Erosion
Undersea volcanism
Minor fluctuation in external gravitational forces
Minor fluctuation in earth’s gravitational force
Thermal expansion
All of those ARGO buoys
File sea level rise under non-issue.
Good article on sea levels: click
Allan M R MacRae: You wrote, āIf you have time, please plot seasonal (monthly) sea level vs the seasonal CO2 sawtooth data, and let us know what you findā¦ Suggest you use Mauna Loa CO2 and Pacific Ocean.ā
The CO2 curve shows an almost constant rise with a seasonal signal, while the Sea Level curve shows significant year-to-year variability.
http://i29.tinypic.com/vytoqw.png
Bob,
Are you using the University of Colorado’s “inverse barometer” adjusted graph. The warmists seem to prefer it, but there’s a glaring mistake in it.
Their web site, is http://sealevel.colorado.edu/.
It shows the graph you often refer to.
If you click on this link on that page: mean sea level time series you go to a page where you can choose an option for āInverted barometer appliedā. That gives you the graph that the alarmists like to use, as it shows the sea level still rising.
The first graph shows a decreasing trend since 2006.Ā The second shows an increasing trend.Ā The whole of the second graph has been moved up about 10mm of sea level.
Their first webpage has a link for documentation, which has the formula they use for the adjustment:
Inverted Barometer = -9.948*(1013.3 – global_average_pressure)
It also states “The inverted barometer does not have much apparent effect on the global mean sea level because the ocean as a whole is not compressible.”. However, moving the whole graph up byĀ nearly 20%, and changing the slope of the most recent period is a very apparent effect.
The problem lies in the coefficient in the formula: -9.948 mm/millibar
If the air pressure at one place over the ocean decreases by 1 millibar, the sea level will rise by about 9mm. Ā But, the water has to come from somewhere that has a higher air pressure, and the sea level at that place must fall.Ā When you take the global average, they cancel out because moving water from one place to another canāt affect the average.Ā Thereās still the same amount of water.Ā I can see where the 9.948 came from. Ā One atmosphere of pressure holds up a column of water about 9 metres high, so 1 millibar equates to about 9 mm.Ā Thatās correct for local effects such as storm surges, but someone mistakenly used it for a global average.
This is the correct calculation, in accordance with the statement that āThe inverted barometer does not have much apparent effect on the global mean sea level because the ocean as a whole is not compressible.ā:
The compressibility of water is 5.1×10-5 bar-1. The average depth of the ocean is 3790 metres.Ā Both those figures are from Wikipedia but they seem about right.Ā One bar would compress water by a factor of 5.1×10-5 so a millibar would give about 5.1×10-8. Ā Multiplying by 3970 metres gives 0.000202 metres per millibar, which is 0.202 mm per millibar.Ā The formula has 9.948, which is out by a factor of nearly 50.
The formula should be
Inverted Barometer = -0.202 *(1013.3 – global_average_pressure)
I suspect that the adjustment for inverse barometer, when using the correct formula, would be truly insignificant.
I’ve asked them to correct their formula. I’ll let you know what happens.
The other interesting thing is why alarmists go to such lengths to get to the erroneous graph, when the correct one, which you use, is right there on the first page. I think it’s like Simon and Garfunkle said “we see what we want to see, and disregard the rest.
I think this is a very important issue. I couldn’t figure out why alarmists have been saying the sea level is rising, when the University of Colorado says it’s falling, as you have mentioned many times. Now I know that there’s a mistake on their website, causing them to show an erroneous graph that the alarmists are referring to.
The following URL’s suggest perspectives that may prove interesting:
http://www.appinsys.com/GlobalWarming/EarthMagneticField.htm
http://www.iop.org/News/news_35352.html
Regards,
If the map of flooded Florida is an accurate projection, why in the hell are the Feds wasting our money trying to restore the Everglades if its all just going to be drowned in saltwater anyway? Or maybe the sea level scare is just another way to get our money. Nah, the Feds are always working to make our lives better. Especially Obama.
Carl Chapman: You asked, “Are you using the University of Coloradoās āinverse barometerā adjusted graph.”
No.
And thanks for the discussion on the inverse baramoter adjustments.
Regards
<blockquoteCarl Chapman (02:54:31) :
Bob,
But, the water has to come from somewhere that has a higher air pressure, and the sea level at that place must fall. When you take the global average, they cancel out because moving water from one place to another canāt affect the average. Thereās still the same amount of water. I can see where the 9.948 came from. One atmosphere of pressure holds up a column of water about 9 metres high, so 1 millibar equates to about 9 mm.
So Bob, what about the land area! You have seemingly forgotten/ignored the fact that pressure changes over land as well as the oceans. You have correctly stated that increases air pressure reduces ocean level locally and decreased air pressure increases it, this is why the inverse barometer should be used. I hope the guys at UC are kind to you.
Florida has been there before! The land area of Florida has shrunk by more than 50% over the past 12,000 years as sea levels rose after the last ice age ended. See the University of Florida geological study at; “edis.ifas.ufl.edu/document_uw208”
Dumb question: If the Indian Ocean has gone up an inch, shouldn’t the other oceans go up a bit as well (perhaps after a delay?) After all, they are somewhat connected.
On a previous thread, sea level measurements were given an uncertainty of 4mm. I assume this is from satellites. That’s about 12 picoseconds (really double as it is round trip time) assuming they use radar. 25 ps. And assuming you know the location of the satellite to within 4mm. The ocean is seldom flat, tides and weather bounce things around, the moon tugs on the satellites, and atmospheric propagation delay varies by a whole lot more than 25ps. Measuring ocean levels to that claimed precision would be like claiming to measure land surface temperatures to 0.1C with a bunch of uncalibrated and poorly sited measuring stations.
Oh, wait …
Mary Hinge: You wrote, “So Bob, what about the land area! You have seemingly forgotten/ignored the fact that pressure changes over land as well as the oceans. You have correctly stated that increases air pressure reduces ocean level locally and decreased air pressure increases it, this is why the inverse barometer should be used. I hope the guys at UC are kind to you.”
This should be directed to Carl Chapman, not to Bob. You’re quoting Carl, not Bob. I did not state, mention or imply, “that increases air pressure reduces ocean level locally and decreased air pressure increases it…” Air pressure never came up in MY post or MY comments.
And I would think the guys at UC would appreciate my post. All I did was reformat their data so that I could compare it to NINO3.4 SST anomaly data. Nothing contraversial there. Just some wiggle matching.
Regards
OT but interesting, and probably correct.
Regards, Allan
‘Surge in global temps since 1977 can be attributed to a 1976 climate shift in the Pacific Ocean’
Wednesday, July 22, 2009 – By Marc Morano ā Climate Depot
A new peer-reviewed climate study is presenting a head on challenge to man-made global warming claims. The study by three climate researchers appears in the July 23, 2009 edition of Journal of Geophysical Research. (Link to Abstract)
Full Press Release and Abstract to Study:
July 23, 2009
Nature not man responsible for recent global warming
Three Australasian researchers have shown that natural forces are the dominant influence on climate, in a study just published in the highly-regarded Journal of Geophysical Research. According to this study little or none of the late 20th century global warming and cooling can be attributed to human activity.
The research, by Chris de Freitas, a climate scientist at the University of Auckland in New Zealand, John McLean (Melbourne) and Bob Carter (James Cook University), finds that the El NiƱo-Southern Oscillation (ENSO) is a key indicator of global atmospheric temperatures seven months later. As an additional influence, intermittent volcanic activity injects cooling aerosols into the atmosphere and produces significant cooling.
“The surge in global temperatures since 1977 can be attributed to a 1976 climate shift in the Pacific Ocean that made warming El NiƱo conditions more likely than they were over the previous 30 years and cooling La NiƱa conditions less likely” says corresponding author de Freitas.
“We have shown that internal global climate-system variability accounts for at least 80% of the observed global climate variation over the past half-century. It may even be more if the period of influence of major volcanoes can be more clearly identified and the corresponding data excluded from the analysis.ā
Climate researchers have long been aware that ENSO events influence global temperature, for example causing a high temperature spike in 1998 and a subsequent fall as conditions moved to La NiƱa. It is also well known that volcanic activity has a cooling influence, and as is well documented by the effects of the 1991 Mount Pinatubo volcanic eruption.
The new paper draws these two strands of climate control together and shows, by demonstrating a strong relationship between the Southern Oscillation and lower-atmospheric temperature, that ENSO has been a major temperature influence since continuous measurement of lower-atmospheric temperature first began in 1958.
According to the three researchers, ENSO-related warming during El NiƱo conditions is caused by a stronger Hadley Cell circulation moving warm tropical air into the mid-latitudes. During La NiƱa conditions the Pacific Ocean is cooler and the Walker circulation, west to east in the upper atmosphere along the equator, dominates.
“When climate models failed to retrospectively produce the temperatures since 1950 the modellers added some estimated influences of carbon dioxide to make up the shortfall,” says McLean.
“The IPCC acknowledges in its 4th Assessment Report that ENSO conditions cannot be predicted more than about 12 months ahead, so the output of climate models that could not predict ENSO conditions were being compared to temperatures during a period that was dominated by those influences. It’s no wonder that model outputs have been so inaccurate, and it is clear that future modelling must incorporate the ENSO effect if it is to be meaningful.”
Bob Carter, one of four scientists who has recently questioned the justification for the proposed Australian emissions trading scheme, says that this paper has significant consequences for public climate policy.
“The close relationship between ENSO and global temperature, as described in the paper, leaves little room for any warming driven by human carbon dioxide emissions. The available data indicate that future global temperatures will continue to change primarily in response to ENSO cycling, volcanic activity and solar changes.ā
āOur paper confirms what many scientists already know: which is that no scientific justification exists for emissions regulation, and that, irrespective of the severity of the cuts proposed, ETS will exert no measurable effect on future climate.ā
—
McLean, J. D., C. R. de Freitas, and R. M. Carter (2009), Influence of the Southern Oscillation on tropospheric temperature, Journal of Geophysical Research, 114, D14104, doi:10.1029/2008JD011637.
This figure from the McLean et al (2009) research shows that mean monthly global temperature (MSU GTTA) corresponds in general terms with the Southern Oscillation Index (SOI) of seven months earlier. The SOI is a rough indicator of general atmospheric circulation and thus global climate change. The possible influence of the Rabaul volcanic eruption is shown.
Excerpted Abstract of the Paper appearing in the Journal of Geophysical Research:
Time series for the Southern Oscillation Index (SOI) and global tropospheric temperature anomalies (GTTA) are compared for the 1958-2008 period. GTTA are represented by data from satellite microwave sensing units (MSU) for the period 1980ā2008 and from radiosondes (RATPAC) for 1958ā2008. After the removal from the data set of short periods of temperature perturbation that relate to near-equator volcanic eruption, we use derivatives to document the presence of a 5- to 7-month delayed close relationship between SOI and GTTA. Change in SOI accounts for 72% of the variance in GTTA for the 29-year-long MSU record and 68% of the variance in GTTA for the longer 50-year RATPAC record. Because El NiƱo-Southern Oscillation is known to exercise a particularly strong influence in the tropics, we also compared the SOI with tropical temperature anomalies between 20Ā°S and 20Ā°N. The results showed that SOI accounted for 81% of the variance in tropospheric temperature anomalies in the tropics. Overall the results suggest that the Southern Oscillation exercises a consistently dominant influence on mean global temperature, with a maximum effect in the tropics, except for periods when equatorial volcanism causes ad hoc cooling. That mean global tropospheric temperature has for the last 50 years fallen and risen in close accord with the SOI of 5ā7 months earlier shows the potential of natural forcing mechanisms to account for most of the temperature variation.
Received 16 December 2008; accepted 14 May 2009; published 23 July 2009. [End Abstract Excerpt]
Bob Tisdale (02:41:11) :
Allan M R MacRae: You wrote, āIf you have time, please plot seasonal (monthly) sea level vs the seasonal CO2 sawtooth data, and let us know what you findā¦ Suggest you use Mauna Loa CO2 and Pacific Ocean.ā
The CO2 curve shows an almost constant rise with a seasonal signal, while the Sea Level curve shows significant year-to-year variability.
http://i29.tinypic.com/vytoqw.png
*************
Thank you Bob. I’ve always found it interesting that CO2 and sea level both have a clear seasonal cycle.
I think we understand the driver of the seasonal CO2 cycle, which ranges from almost 20ppm in the far North to near-zero at the South Pole. It is the dominance of the larger Northern Hemisphere landmass and its seasonal photosynthetic cycle, reducing CO2 in the NH summer and increasing in the NH winter.
What do you think are the largest drivers of the seasonal cycle in sea level measurements?
Sorry Bob, got a bit mixed up with the cut and paste so apologies.
I will redirect my question to Carl and ask why he has omitted 25% of the Earth’s surface in his calculation?
Sea Level Rise; A Major Non-existent Threat Exploited by Alarmists
By Dr. Tim Ball Monday, July 6, 2009
Sea level is not level. This is a surprise to most people and enough to make claims of changing level questionable. For example, it is different at each end of the Panama Canal yet the Pacific and Atlantic Oceans are connected at the both ends of the Americas. Sea level varies with changes in atmospheric pressure. It can rise up several meters over very large areas under large low-pressure systems. This is a factor in dramatic sea level rise when hurricanes approach land. It can vary with winds piling it up in one area and removing it in another. It varies with variations in crustal density.
Hotdog, looks like Florida will be a great place for crabbing and fishing. Getting rid of all those selfish beach dwellers!
Hi folks, Iām a geologist from Turin, NW Italy.
20 years ago, back at university, a professor of mine (a senior geologist, with almost 40 years spent working in the field, mainly in Quaternary researches) was telling us that, in the geological record, most of the changes in sea level (āeustaticā movements) were caused by changes in the rate of plate tectonics, i.e. the rate of sea floor spreading.
With a faster spreading, the middle oceanic ridges will ābulgeā (they rise up to 3000 m from the bottom of the ocean), moving upward the floor of the oceans and displacing a larger volume of water, thus leading to a rising sea level.
During periods of tectonic āpauseā, a slower spreading will lead to a faster cooling of the whole oceanic ridges (they are made of basalts), causing them to āshrinkā, reducing their volume and so leading to a fall in the sea level.
Thanks to satellite measurements, now we can measure the rate of continental drift and ocean spreading (IIRC, in the Atlantic itās more or less 20 ā 40 cm/year) at least back to the early ā80s.
We have also some āproxyā data to measure the rate of tectonic activity: the number and magnitude of earthquakes worldwide, the number and magnitude of volcanic eruptions and so on, more or less like the sunspot number to measure the Sunās activity.
Well, it could be really interesting to compare the rate of tectonic spreading vs. sea level, just to see if thereās some correlationā¦..
Not to mention that a faster tectonic spreading means more geothermic heat released from the floor of the ocean: time ago, Iāve read something about researches correlating the El Nino events with increased tectonic and magmatic activity in the Nazca plate (and showing a really GOOD correlation).
Just my 2 cents
PS sorry for my English, I wish it could be more fluentā¦
Amyone, I have heard that the SL satelite measurements are partially calibrated by tide guages. If this is true then the guages selected could invest a bias. Has this been studied, and if so what are the results?
Fascinating info as always.
Sea level varies by so many different factors. I’m seeing:
ā¢ the moon’s gravity
ā¢ localized air pressure variations
ā¢ currents affect distribution of seawater / pooling affects currents / containment affects pooling
ā¢ geographical containment: the shape of each basin and the size of inflow / outflow to adjacent basins
ā¢ salinity affects volume / glacial meltwater affects salinity / volcanism affects glacial meltwater
ā¢ localized temperature expansion and contraction affects volume
ā¢ solar gain: less cloud cover = more heating
ā¢ earth’s 23 degree tilt, 24 hour day, 365.25 day year / majority of land in northern hemisphere affects solar gain
ā¢ volcanic aerosols cause pronounced cooling effect especially at low or high latitudes
ā¢ new research suggests that cloud cover is influenced by cosmic rays
ā¢ cosmic ray intensity influenced by variations in the height of earth’s atmosphere which is unusually low possibly due to very low solar output which reduces the atmospheric volume by reducing atmospheric solar heating
ā¢ changes in each basin’s size, shape, and interface to other basins due to plate techtonics, volcanism and many other factors
ā¢ biological inputs such as large algae blooms might influence the system, fertilizer runoff influence algae blooms
ā¢ possible human-caused inputs: runoff pollution / sewage and other ocean dumping, runoff heating caused by pavement and roofs, particulate pollution affects air clarity, mercury pollution caused by coal burning affects ocean biology
ā¢ the entire water cycle affects sea level: clouds are key
What other factors influence sea level?
This is just one incredibly complex aspect of the overall global climate. Computers cannot possibly model gloabl climate accurately. The complexity of the system is awe-inspiring…
Since I live here that picture is so stupid I would have thought the computer would have refused to create it.
Mary Hinge: You wrote, āSo Bob, what about the land area! You have seemingly forgotten/ignored the fact that pressure changes over land as well as the oceans.”
Changes in the air pressure over land areas aren’t going to affect the sea levels. I’m sorry, but I can’t see your point.
Dario (09:53:42) :
Hi folks, Iām a geologist from Turin, NW Italy.
20 years ago, back at university, a professor of mine (a senior geologist, with almost 40 years spent working in the field, mainly in Quaternary researches) was telling us that, in the geological record, most of the changes in sea level (āeustaticā movements) were caused by changes in the rate of plate tectonics, i.e. the rate of sea floor spreading.
With a faster spreading, the middle oceanic ridges will ābulgeā (they rise up to 3000 m from the bottom of the ocean), moving upward the floor of the oceans and displacing a larger volume of water, thus leading to a rising sea level.
During periods of tectonic āpauseā, a slower spreading will lead to a faster cooling of the whole oceanic ridges (they are made of basalts), causing them to āshrinkā, reducing their volume and so leading to a fall in the sea level.
Thanks to satellite measurements, now we can measure the rate of continental drift and ocean spreading (IIRC, in the Atlantic itās more or less 20 ā 40 cm/year) at least back to the early ā80s.
We have also some āproxyā data to measure the rate of tectonic activity: the number and magnitude of earthquakes worldwide, the number and magnitude of volcanic eruptions and so on, more or less like the sunspot number to measure the Sunās activity.
Well, it could be really interesting to compare the rate of tectonic spreading vs. sea level, just to see if thereās some correlationā¦..
Not to mention that a faster tectonic spreading means more geothermic heat released from the floor of the ocean: time ago, Iāve read something about researches correlating the El Nino events with increased tectonic and magmatic activity in the Nazca plate (and showing a really GOOD correlation).
Just my 2 cents
PS sorry for my English, I wish it could be more fluentā¦
Dario, your English is fine, thanks for this posting.
I always have assumed that “spreading” would lower the ocean levels.
Thanks for correcting this assumption.
Very interesting.
We are talking about incredible area’s here involving massive volumes of ocean floor and water. It’s a very viable theory which can be tested here.
Tom in high and dry Florida (17:48:32) :
The Florida āscareā map gives me a chuckle. I am located on the central west coast about half way between Tampa Bay and Port Charlotte Harbor. I live about 1 mile inland from the Gulf and this map has me in blue. Umm, one slight problem though, the official elevation certificate for my house used for flood insurance has me at 15 feet above sea level. So either the map is a load of crap or sea levels will have to rise over 15 feet for this to be an accurate representation. I believe it is the former.
Don’t worry too much Tom,
Most of the Dutch live 15 meters below sea level.
No problem at all.
Bob Tisdale (02:41:11) “The CO2 curve shows an almost constant rise with a seasonal signal, while the Sea Level curve shows significant year-to-year variability.
http://i29.tinypic.com/vytoqw.png
“
The way to bring out the interannual variability in CO2 is to look at the annually-integrated rate of change. (Recall Dr. Spencer’s WUWT post from a while back – he arrived at a similar result via a similar approach.) There’s a good (but somewhat intermittent) match with LOD, SOI, AAM, T, & SST. (Differencing & annual-integration are necessary for some of these series to see the phase-relationship. For example, LOD needs to be differenced & annually-integrated twice.)
Bob, thanks for pointing my attention towards some new series to investigate. The suppression of the annual cycle in the Pacific is very interesting. This suggests an array of opportunities to learn something very important from the temporal pattern of quantitative spatial contrasts. (This is one of the ways we get around the lack of information contained in global annual averages.)
Note the overall “fear factor” and “Al Gore’s scary movie effect” that control this propaganda about rising ocean levels.
Hansen’s, Pelosi’s, Obama’s, and Gore’s entire propaganda effort is “heat” and “hot air” -> which means that (obviuously) temperatures. Never mind that temp’s actually only went up less than 1/2 of one degree upthrough 1998, and have decreased since 1998 by about 3/10 of one degreee. They don’t want you knowing “numbers” – they want you fearing technology do you give them control of your life and money!!
After exaggerating the 1/2 of one degree increase, and then extrapolating it several centuries until “catastrophe” is “obviously” upon us, they then wave their hands magically and get you assuming that the final temperature will be enough to melt the ice caps. (Reasonable, in its own way, since in the colder extremes, CO2 IS (correctly) much more prominent in reflecting heat radiation than water vapor since the relative humidity is so much less. With very, very little water vapor, an increase in CO2 does increase the reflection of radiation – just not as much as they are getting you to fear.)
So now that they have (the world) convinced that catastropic warming will happen in the far north and south, obviously the ice will melt -> and obviously that will raise sea levels (since the melted ice has to go somewhere -> and so sea levels must rise! (Add to this the “feedback” of black paper on white ice = more open ocean is (wrongly!) theorized to yield more open water that in turn increases the heat absorbded by the ocean and so it melts more ice… (Except that sea ice extents in the real world don’t work this way, as shown by the ice recovery from 2006 to 2007 to 2008 to the record highs sea ice extents of spring 2009!)
Realize also that the simple Mercator projection maps of most classrooms and textbooks make Greenland look twice as large as Brasil … Can you see how he exaggerates the fears of the gullible?)
So the rising sea levels (in actual levels of mm per year) are the result od carefully developed fears that are not based on real world facts.
Dario,
Your English is excellent. My Italian needs much work.
As to continental drift and ocean levels, my initial thought was it would have zero effect. After all, as one ocean basin expands laterally, another must contract. All the continents cannot move away from each other.
However, you bring up a good point about mid-ocean ridges growing as continental plates drift apart. What is needed is a measurement of the ocean basin volume. I think the U.S. Navy has good sea-floor maps, but they may consider the data too valuable militarily to disclose. Perhaps there are other non-military sources of data.
Interesting. However not a word is mentioned about land-rise and land-fall.
.
Such a thing ~does~ happen and is subject to several agencies, two of which are excessive extraction of ground water and gravitational influences caused by the Sun and Moon.
.
I wonder: WHERE are those measurements are being made, and are they in areas of high human occupancy?
.
Are any of them in locations where there is little or no human occupancy?
.
If you get my drift here, this is not unlike the UHI (Urban Heat Island) situation.
.
Just a thought.
Carl Chapman (15:59:20) :
Mary Hinge: You wrote, āSo Bob, what about the land area! You have seemingly forgotten/ignored the fact that pressure changes over land as well as the oceans.ā
Changes in the air pressure over land areas arenāt going to affect the sea levels. Iām sorry, but I canāt see your point.
—————–
I would have thought that a decrease in atmospheric pressure would permit the water beneath it to expand, not to be supplemented by water flowing in from the sides. In fact, at least on a local scale, this expanded water should flow away to the areas of high atmospheric pressure, where the water has not expanded. Whether there’s a net rise of the surface level or not should depend on the extent of the atmospheric low. I can’t imagine that any of this can be measured so precisely.
To Oliver Ramsay.
History of comments:
Mary Hinge: You wrote, āSo Bob, what about the land area! You have seemingly forgotten/ignored the fact that pressure changes over land as well as the oceans.ā
Changes in the air pressure over land areas arenāt going to affect the sea levels. Iām sorry, but I canāt see your point.
āāāāāā
Oliver Ramsay wrote: I would have thought that a decrease in atmospheric pressure would permit the water beneath it to expand, not to be supplemented by water flowing in from the sides. In fact, at least on a local scale, this expanded water should flow away to the areas of high atmospheric pressure, where the water has not expanded. Whether thereās a net rise of the surface level or not should depend on the extent of the atmospheric low. I canāt imagine that any of this can be measured so precisely.
My reply to Oliver:
You’re right. A change in air pressure will expand or contract the water in the ocean. The effect is about 1/50 th of the errronous multiplier that the Uni of Colirado use. They use 9.948 mm/millibar, which is the multiplier for moving water from a high pressure area to a low pressure area (no affect on the average). The multiplier that you refer to, for compression of water is roughly 0.202 mm/millibar, which is smaller than the measurement errors.
This is a copy of my original comment.
The alarmists also show a graph from the Colorado Uni showing the sea level rising. I thought that was strange, so I checked and found an error in their adjustment for “inverse barometer”.
Their web site, is http://sealevel.colorado.edu/.
It shows the graph you often refer to.
If you click on this link on that page: mean sea level time series you go to a page where you can choose an option for āInverted barometer appliedā. That gives you the graph that the alarmists like to use, as it shows the sea level still rising.
The first graph shows a decreasing trend since 2006.Ā The second shows an increasing trend.Ā The whole of the second graph has been moved up about 10mm of sea level.
Their first webpage has a link for documentation, which has the formula they use for the adjustment:
Inverted Barometer = -9.948*(1013.3 – global_average_pressure)
It also states “The inverted barometer does not have much apparent effect on the global mean sea level because the ocean as a whole is not compressible.”. However, moving the whole graph up byĀ nearly 20%, and changing the slope of the most recent period is a very apparent effect.
The problem lies in the coefficient in the formula: -9.948 mm/millibar
If the air pressure at one place over the ocean decreases by 1 millibar, the sea level will rise by about 9mm. Ā But, the water has to come from somewhere that has a higher air pressure, and the sea level at that place must fall.Ā When you take the global average, they cancel out because moving water from one place to another canāt affect the average.Ā Thereās still the same amount of water.Ā I can see where the 9.948 came from. Ā One atmosphere of pressure holds up a column of water about 9 metres high, so 1 millibar equates to about 9 mm.Ā Thatās correct for local effects such as storm surges, but someone mistakenly used it for a global average.
This is the correct calculation, in accordance with the statement that āThe inverted barometer does not have much apparent effect on the global mean sea level because the ocean as a whole is not compressible.ā:
The compressibility of water is 5.1×10-5 bar-1. The average depth of the ocean is 3790 metres.Ā Both those figures are from Wikipedia but they seem about right.Ā One bar would compress water by a factor of 5.1×10-5 so a millibar would give about 5.1×10-8. Ā Multiplying by 3970 metres gives 0.000202 metres per millibar, which is 0.202 mm per millibar.Ā The formula has 9.948, which is out by a factor of nearly 50.
The formula should be
Inverted Barometer = -0.202 *(1013.3 – global_average_pressure)
I suspect that the adjustment for inverse barometer, when using the correct formula, would be truly insignificant.
I’ve asked them to correct their formula. I’ll let you know what happens.
The other interesting thing is why alarmists go to such lengths to get to the erroneous graph, when the correct one, which you use, is right there on the first page. I think it’s like Simon and Garfunkle said “we see what we want to see, and disregard the rest.
I think this is a very important issue. I couldn’t figure out why alarmists have been saying the sea level is rising, when the University of Colorado says it’s falling, as you have mentioned many times. Now I know that there’s a mistake on their website, causing them to show an erroneous graph that the alarmists are referring to.
Bob Tisdale
Good article. Looking at the ATLANTIC OCEAN SEA LEVEL & SCALED NINO3.4 SST ANOMLAIES graph , I can see the possible effect of 5 EL Ninos. There could be a base rise of the ATLANTIC OCEAN level, independent of the El Nino any way during these periods that is only perhaps amplified by the EL Nino , the extent of which is not clear. I counted at least 8 other sea level peaks , that seem to be unrelated to ENSO. [ like late1995,late 1998, late 1999, 2000, 2001,2003, 2008] .So I think the ocean level rises in the Atlantic are also caused by internal changes like AMO, seasonal warming ,etc.[ as the peaks seem to occur at the latter part of the year]
Regarding sea levels, an interesting article on unusually high tides along the U.S. Atlantic coast recently.
Quote from the article: “Since June, tides have been running from 6 inches to 2 feet above what would normally be expected, even considering seasonal and lunar fluctuations. While local tidal changes are not uncommon, researchers for the National Oceanic and Atmospheric Administration aren’t sure they have ever recorded an event like this one, which is showing up all the way from Maine to Florida.” [bold emphasis added – RES]
The article goes on to state that they are sure it is not due to global warming.
http://www.charlotteobserver.com/local/story/852054.html
That article about NOAA and unusual high tides (that NOAA failed to predict because they do not understand what is going on) is especially good, considering NOAA’s rather “modest” self-proclamation:
“NOAA understands and predicts changes in the Earthās environment, from the depths of the oceans to surface of the sun, and conserves and manages our coastal and marine resources.”