I got a couple of emails today saying that I should take a look at the most recently posted sea level graph from the University of Colorado shown below:
The reason for the interest is that it dropped the rate of change from 3.3 mm/yr to 3.2 mm/yr. as shown in the next graph. That’s hardly news, since it is well within the error band of +/- 0.4 mm/yr.
But I thought it might be interesting to go back and see what I could find in the UC sea level archive of graphs. I’ve presented all of the ones I’ve found below. I should note that in some years, UC may only release 2 graphs (as indicated by the release #) or up to 5 in one year like they did in 2005. For the sake of presentation simplicity, I’m only presenting the last graph to be released in any year.
I realize there has been a great deal of interest in the flattening of the 60 day smoothing line that started in 2007 and continues to the present. But the trend line will take awhile to reflect any appreciable change in the rate if it continues to flatten. The yearly rate of rise has been between 3.0 and 3.5 mm per year since 2004.
Many projections by various models predict the rise of sea level:
Note the trend of the observations line from 1950 to 2000, if you follow the linear trend, it will end up somewhere between 20 and 30 cm by the year 2100. The graph above is from Wikipedia’s “global warming art” which for some reason doesn’t show the observations back that far.
Here is a better graph, from New Zealand’s Ministry of the Environment, which shows more of the historical record, all the way back to 1870:
It seems sea level has been rising for awhile, and that the observation line in black, if you follow the linear trend, will also end up somewhere between 20 and 30 cm by the year 2100.
To put it all in perspective, some example images are useful.
Here is what 3 millmeters of sea level rise in 1 year looks like. This is a tiny fuel cell chip, just 3mm x 3mm in size:
I know that many people are concerned about sea level rise over the next century. In the rate of 3 mm per year continues, we’d be at 300 mm (30 centimeters) of rise in 100 years. Here is what 30.48 cm (12 inches) looks like:
And finally, here is what the tide gauge at Anchorage Alaska looks like:
Anchorage Alaska boasts the world’s second highest tides: varying over 40 feet (1219 cm), low to high tide. Ok, that is an extreme example, how about this one in France:
Mt. St. Michel on the north coast of France at low tide (left) and high tide (right).
The water surrounding this island is the Gulf of Sant-Malo.
Low tide
The point I’m making is that in 100 years, for some places that extra foot won’t make much of a difference. Some low lying areas will be affected certainly, but even some of the lowest lying areas of the earth won’t see all that much impact from a third of a meter of sea level rise in 100 years. Probably the worst place to live is in a river delta which is almost at sea level anyway. Even so, 30 cm falls short of the lowest notch on this graph of 1 meter.
Bangladesh is another low lying river delta where it is not desirable to live, yet many do. Even so it appears much of it is 1 meter or more above sea level.
Florida is often talked about as being at risk. yes there are a few places there that might be touched by a 30 cm rise in sea level 100 years from now.
Looking at the whole world, at the rate we are going, I’d say it will take awhile.
How much of the rise can be attributed to siltation from rainfall and wind eroding land mass above sea level?
The Port of Auckland Mean Annual Sea Level graph seems to dance about like a fiddlers elbow… up and down… with some big changes over a small periods of time. This made me wonder how can anyone really be estimating a Global Sea Level figure with any real accuracy… measuring all point simultaneously and allowing for all the high and low tides… and what about the height of the waves… and what impact might plate tectonics have over a period of a 100 years… mmmm…. then i saw the graph caption: Seasonal Signals Removed… and i thought: Here we go again; data massaging…. Then i was thinking back:
How many times have i seen waves less than 30cm high?
So are these Sea Level graphs really accurate, factual or meaningful?????
Then I started Googling and found: http://www.mfe.govt.nz/publications/climate/coastal-hazards-climate-change-guidance-manual/html/page20.html
And this does seem to indicate that this science is really an art form…..
QUOTE
Longer-term fluctuations (lasting at least a month) in the mean level of the sea are important components when assessing inundation and erosion hazards. These fluctuations are typically related to:
1) The annual heating and cooling cycle caused by the influence of the sun on the ocean. Mean sea levels tend to be higher in late summer and autumn and, over a year, can fluctuate around ± 0.04 m on average, but up to ± 0.08 m in some years.
2) Interannual 2–4 year El Niño-Southern Oscillation (ENSO) cycles. Mean level of the sea is depressed during El Niño phases, and is higher during La Niña phases, with fluctuations of up to ± 0.12 m on both east and west coasts of the upper North Island. An analysis of the magnitude of fluctuations further south is currently underway.
3) Interdecadal 20–30 year Interdecadal Pacific Oscillation (IPO) cycles. The rate of sea-level rise tends to be higher during negative phases of IPO and tends to flatten out during the positive phases of IPO. The IPO facilitates sea-level fluctuations of up to ± 0.05 m. The IPO has been in a negative phase since about 1999.
UNQUOTE
So looking at your Auckland graph it looks like the HIGH WATER mark was reached in the late 1940s and that the curve then started on a downwards trend… and that seems to have a familiar ring to it somehow…
I know i really enjoy a massage…. but i do not extend this luxury to data…
“DJ (01:33:42) :
3mm rise per year will lead to an average coastal recession of 3cm to 30cm per year for sandy beaches – that puts places like Florida in line for more than 100 feet of coastal recession this century with a low end sea level rise. This
……….
Craig Allen (01:02:02) :
Just eight points I’d like to make.
………”
Perhaps valid points but if you build a house on a flood plain, don’t be surprised when it gets flooded.
Sea levels rise, and fall, over time.
Gerard (01:47:55) :
This is my view on the ice shelves breaking off.
It is my feeling that the ice shelves do not indicate current or recent conditions, but rather, an accumulation of various effects over time. During the LIA they were exposed to SST’s which were much cooler.
The record indicates that, from 1701 to 1761, surface temperatures were on average 1.4°C cooler than during the past 30 years. ( Source: http://cat.inist.fr/?aModele=afficheN&cpsidt=1132291 )
At other times the oceans in the area have been much warmer (Holocene Climate Maximum, Roman Warm Period, Medieval Warm Period, etc). Yes, some of the Ice lost has been tens of thousands of years old. However, 40,000 years ago their reach over the ocean was most likely much further. A lot has changed in the past 10,000 years, the warming into the Holocene. That warming and 10,000 years of the interglacial, 10,000 years of temps 8 degrees warmer than when they formed, 10,000 years of warmer seas beating on them is what the break-off’s reflect. A process which started long before fossil fuels.
To some extent, ice shelves are a poor climate indicator, they react to slowly. The story they tell is at times the same story that Glaciers which do not have a coastal edge tell. I did a brief blog on The Story of Glaciers not long ago.
http://penoflight.com/climatebuzz/?p=88
Having been attached and anchored the shelves will add to sea level, but, only the portion / volume of them that was previously above the water will be an addition.
Correct me if I’m wrong. But, isn’t these satelite numbers adjustet against the Hong Kong tide gauge??? And Hong Kong is sinking 2-3mm/year. Could this leveling of mean that hong Kong has stopped sinking? 😉
re Gerard – the same story was published in our online newspaper. The article claimed unprecedented ice loss and whopping 3°C warming in Antarctic! It was fun to debunk that junk in following discussions by linking to the (increasing) southern ice anomaly and (decreasing) southern polar satellite temperature record. Another folks got their eyes open, I would say.
Now that the Antarctic ice shelf has collapsed sea levels will show a sharp rise in levels. The Penguin populations of Antarctica will be threatened due to having to dive deeper for food after years of suffering altitude sickness from being elevated on top of a thickening ice sheet.
Peter Garret, Australian environment minister had this to say while moving his arms in a strange manner in relation to his hips.
“I don’t think that there’s any doubt that global warming is contributing to what we’ve seen both on the Wilkins Ice Shelf and also more generally in Antarctica,” he said.
“And it is the case that scientists, because of the fact of the Antarctic’s unique and critical role in the world’s climate system, are focusing very strongly on climate change research and also potential impacts.
“This is a really significant mass of ice and it is the case that scientists previously had identified that it might potentially start to break away or collapse and that that would be as a consequence of warming.”
Mr Garrett has dismissed the suggestion the shelf’s collapse is simply the latest in a very long history of such events. Doh !
http://www.abc.net.au/news/stories/2009/04/07/2536710.htm
He has the power and the passion.
The fact is sea level are flatlining now since 2006 are may actually start to decline…..due to reduced watts/mt from the sun. There is also a hint that Co2 levels are starting to do same.. very speculative but there are signs…re Peter Garrett should stay with his music band (or really learn some meteorology or like) LOL
@Craig
there are thousands of scientist out there, who have the mission to figure out the dyre consequences of the projected sea level rise and they are very creative in doing this.
the ipcc projections, however, are not much different from the experience of the last century, and hardly anybody did take notice in the past or suffer from anything related to the rise. the previous 30 cm sea level rise was a non-event and the next 30 cm rise (if it happens at all) will be the same.
OT but this cooling (forecasts) seems to be worldwide and pretty obviously becoming more persistent and verifiable
http://wxmaps.org/pix/clim.html go to climate and check each continent Ie USA
http://wxmaps.org/pix/temp1.html ect…
Sid Brooks.. Actually its true I ain’t seen ANY change in sea levels anywhere since I was a child 50 years ago! Has anyone else?
DJ (01:33:42) :
3mm rise per year will lead to an average coastal recession of 3cm to 30cm per year for sandy beaches – that puts places like Florida in line for more than 100 feet of coastal recession this century with a low end sea level rise. This simple fact is captured in Brunn’s rule which is well known to scientists. Here’s some examples of what happens when sea level rise meets people…
Just wondering – do you happen to know of a period since the last ice age when sea levels weren’t rising.
Hey, if you want a large tidal range, don’t forget about the Bay of Fundy up here in Nova Scotia. 😎
http://en.wikipedia.org/wiki/Bay_of_Fundy#Tides
Like Sid Brooks, due to the fineness of variability, I have zero confidence in this data. There are so many uncontrolled variables in this type of measurement as to make the conclusions worthless. Strikes me as more of a case of predicting what you expect rather than what there is. A lot of the methodology I read about, once you strip away all of the complex math and stats, seems to begin with the old saw we learned in early physics classes: “assume a frictionless surface…” Assuming net sum zero uncontrolled variables plus $10 might get you a Starbucks.
DJ (01:33:42) : Part II
Just had a look at one or two of your links. I’m sure this wouldn’t be done deliberately, but the BBC needs to be careful it doesn’t confuse sea level rise due to global warming with other factors such as postglacial rebound and coastal erosion. Note that the Thames area is sinking slowly (and will continue to do so for a good while yet) due to the effects of the LGM. See http://en.wikipedia.org/wiki/Post-glacial_rebound where there is a specific mention of the the Thames problems.
Incidentally Sea Level rises over the past 20,000+ years can be found here:
http://en.wikipedia.org/wiki/Sea_level_rise.
“Gerard (01:47:55) :
6 metre sea level rise
This report on the Wilkins Ice Bridge has been running ABC News Australia for the last couple of days. I am sceptical because everytime there is a conference we have some dramatic event that coincides which supports global warming theories for
….
It has found ice loss has accelerated and the sea level could rise by as much as six metres by the end of the century.
…”
I think as some pointed out above this may be a problem of math challenged individuals. The high estimate of sea level rise on the charts above is 80 cm with the normal predictions being 20 to 60 cm. This could get changed into 6 meters easy enough. Or someone is really extrapolating melt from the western peninsula of Antarctica which has warmed in the last few decades to the whole of Antarctica which is getting colder. Of course it is also possible that the trend is not linear and sea level may drop over the next hundred years.
Alan the Brit (00:08:42) :
I believe our fingernails grow more than this rate per annum.
13 angstroms per second! I remember calculating this in college. I had smashed my finger and measured how fast the bruised area of the fingernail grew back over a few weeks, and this is one of my more astounding “fun facts” from those days… I think it’s reasonably close.
13e-10m/s*3600*24*365=.041m/yr, or 4cm per year. So yes, our fingernails grow MORE THAN 10x faster than sea level rise.
I’ll have to send this message to a couple of my college buddies… HAH! I KNEW this little tidbit would come in handy! Only took 27 years.
Stated another way, sea level is rising 1 micron every 2 HOURS!!!. .0005 inches per day! Run for the hills!
One thing that is’nt mentioned here is that local sea levels are largely dependend on Earth’s gravitational field. “Sea level” to us all means a flat surface over thousends of kilometers, but that’s far from true.
As shown in http://www-app2.gfz-potsdam.de/sec13/animated-potato-e-cms.html sea level differences are up to 200 m in “relatively close” areas as east of South Africa and south of India. 30 cm is nothing in comparison to that entirely natural factor.
I read recently the WAIS is melting at 150 cubic kilometers if ice each year. I make that 136.4 cubic kilometers of water. This will raise sea levels by 0.4mm (zero point four millimeters) which is about the error bar level of all the above graphs. Quite frightening.
Take a look at these:
http://klimakatastrophe.wordpress.com/
The three posts are about sealevel change. Teil 1, Teil 2 and Teil 3.
Even if you don’t understand the german language, the graphics can be understood:
http://klimakatastrophe.wordpress.com/2009/03/22/beschleunigt-sich-der-globale-meeresspiegelanstieg/
http://klimakatastrophe.wordpress.com/2009/03/27/beschleunigt-sich-der-globale-meeresspiegelanstieg-teil2/
http://klimakatastrophe.wordpress.com/2009/03/28/beschleunigt-sich-der-meeresspiegelanstieg-teil3/
Nothing extraordinary…. Im Westen nichts Neues ;-)))
Quoting:
“Many coastal regions are currently protected from storm surges by wetlands and marshes (think New Orleans). ”
Commenting:
Don’t think New Orleans. N.O. is built on a river delta and the surrounding wetlands were drained to make more city. Most of it is well below sea leve and survives only by extensive man-made dikes. The French quarter is above sea level and was not flooded.
It is an absolutely stupid place for a ctiy but it won’t go away. But only an uniformed or dishonest person would try to use it as a scary example of what’s going to happen to Floorida.
Anthony,
Thank you for the article but the illustrations you have added to illustrate the flooding potential caused by sea level rise gives the article a somewhat alarmist impression. There is no reason for any alarm at all.
Why? Because the sedimentation process in accord with the tides will raise the land in the river delta area.
Speaking of Alarmist Propaganda at this moment in time:
The Wilkinson Ice Shelf is making the (political) news again, big media coverage (CNN) directly followed by a comment from Clinton that we finally understand how serious the Global Warming problem is and that we have to act now.
The skeptics now have to show what they are worth now and undertake a counter offensive.
They are seriously trying to put us all in Green Shackles.
CodeTech (00:23:57) :
You missed the big scary one; 300 mm/century. That would give Craig kittens.
In the 2004 graph, the 2003 peak is higher than the 2004 peak.
In the 2005 graph, the 2003 peak is higher than the 2004 peak.
In the 2006 graph, the 2003 peak is now a little lower than the 2004 peak.
In the 2007 graph, the 2003 peak is well below the 2004 peak.
In the 2008 graph, the 2003 peak went back to being higher than the 2004 peak.
In the 2009 graph, the 2003 peak once again became lower than the 2004 peak.
I thought they ‘measured’ this stuff. Did Babe Ruth now hit 64 Home Runs in 1927? Is data really allowed to change so much after the fact?
Craig, using New Orleans is a very poor way of illustrating doom and gloom for sea level rise for very many reasons. First and foremost, New Orleans did not flood because of any sea level rise, it is already below sea level! The New Orleans flood was certainly man made however, it was a failure in maintenance, and as you cited, was warned about for decades!
Seems to me, if you cannot fix something that you know about for decades, something as simple as maintenance, then sea level rise becomes rather moot. If your that stupid, then you should probably drown. I am continually amazed at how people think they can park their rears anywhere they wish and they expect nature to respect them. Such stupidity and arrogance!