(Featured Image Borrowed from The Guardian)
Guest post by David Middleton,
Eric Worrall’s recent essay on the Prime Minister of Tuvalu and his reticence to providing some evidence that his island nation is being inundated by rising sea level inspired me to devise a simple test to see if an island is sinking, vanishing or being washed away:
Planimeter a recent map of the island and compare it to an older map of the island.
Since the USGS has a large historical inventory of topographic maps, this should be relatively easy for any islands in these United States.
For my test case, I chose Key Biscayne, Florida. It’s just south of the perennially sinking Miami Beach, has a maximum elevation of about 5′, is relatively small and the USGS had several vintages of 7.5 minute quadrangles available.
Then…
And Now…
I planimetered the coast lines of each map and found no significant changes over the 51 years from 1962-2012…
I guess I’m going to have to deny climate change or at least doubt the climate, because I can’t see any effect of sea level rise on this puny, flat, little island. (/sarc).
And the heat will expand the water, but freezing will expand it more. Go figure!
Those two little charts side by side totally destroy the whole global warming hoax
They may not “destroy” it… but they clearly demonstrate the insignificance of 3 mm/yr changes in sea level.
Islands can grow larger during sea level rise, y’know. Becoming larger around is no guarantee they are also becoming taller. But enough about my first wife. Seriously, it is entirely possible for an island grow in diameter while heading under the waves.
The island would have to have started out with some “height” to do that or have an up- current source of sediment. Key Biscayne doesn’t fit either of these scenarios. There are no interior uplands from which to source sedimentary accretion. Barrier islands can rapidly move and shape-shift with longshore currents. While USACE can work miracles in retaining beaches and shorelines, these efforts are generally easy to spot in topographic map revisions.
3 mm/yr * 51 yr = 153 mm ~ 6 inches. This should be detectable on an island with a maximum elevation of 5′.
Sandy island?
Sand moves if not protected.
Key Biscayne is sediment-starved due to USACE efforts in the Miami area…
http://serc.carleton.edu/integrate/workshops/risk_resilience/case/82140.html
6 inches of sea level rise should be even more detectable on Key Biscayne than barrier islands to the north.
Reply to oppti ==> Sand subject to wave action moves if not protected is true…but it does not always move off the beach. Wave action brings sand to the beach — that’s how it got there in the first place (in many cases).
I lived near a little beach in Sousa, Dominican Republic for a year, and the beach would have sand added or subtracted from the beach up to five feet in thickness by a single storm, Some days we would have to leap down a five foot cliff off the rocks to the beach — other days just step onto the sand (from the same rocks!). This beach was very unusual in this sense, the speed of removal and replacement of sand, but this is true of all beaches in a general sense.
The sea brings sand and the sea takes away sand. The sea moves sand up and down a beach as well. The sea builds barrier islands and removes them again. The sea fills in inlets along the Carolina shores and cuts barrier islands in pieces, destroying Federal hiways, and creating new inlets.
For Pacific tropical reef-based islands, the creatures of the reef make, create, coral sand which is washed up and accumulates on the island. Waves move it around. Changes to the shoreline can have unpredictable results. Changes to the reef (killing parrot fish) can doom an island altogether. Pumping the fresh water lens out from under a tropical island can sink it.
This is not an easy subject.
Tide gauge data for thousands of sites throughout the world are shown in http://www.psmsl.org/. Some go back over 100 years. Funafuti B is the Tuvulu tide gauge. It goes back only to about 1990, but shows no change since then.
While a tidal record going back only 25 years is not very long, there should still be a 3″ change if the 3mm/y number is correct. 3″ shouldn’t be that hard to detect, even with waves and tides etc. Is Tuvulu a coral island?
The cost of a basket of raw materials has been used in the past to gauge their availability and whether peak supply has been reached. Could a similar method be used to gauge sea level rise? If sea level is rising, then wouldn’t prices of property, currently next to the shore, start to fall in relation to property further inland?
The price of “oceanfront properating in Arizona” would be an excellent metric… /sarc
In the swedish village Ratan, there is a sea level mark hewn in the rock, dated 1741.
That mark is now 2 m above the sea, 7 feet.
That’s due to Post Glacial Rebound.
They argue in millimeters while claiming meters.
Can you overlay the maps and do a blink comparison?
This post is cute, but hardly scientific in any way. Key Biscayne, Florida, is not an example of low-lying tropical Pacific reef-and-sand based islands. Not created or maintained by the same physical mechanisms. It is, in many places, protected by concrete seawalls. Beaches have been “replenished” .
The quesstimate Absolute Sea Level Rise (averaged, worldwide) for the last 100 years is about 8 inches. Daily tides at Key Biscayne run about just under 2.5 feet above MLLW (Mean low low water). Absolute Sea Level Rise does not appear in all places in the local Relative Sea Level Rise. (see my essays on the situation at the Battery in NYC, here and here.)
The important issue is Relative Sea Level Rise — where, at what altitude, does the sea meet the land here?
NOAA CORS (Continously operating gps recorders) shows the land mass in the area of the Florida Keys steady over the short term, no long term data is available. So we don’t know if the land itself is rising or falling (relative to the center of the Earth). NOAA Tides and Currents has Relative Sea Level rise varying from 0-3 Key West) to 3-6 (Marathon Key) back to 0-3 mm/yr (Miami) in the region. This shows that even locally, over ythe length of the Florida Keys, Relative Sea Level trends are variable by 100%, twice in some areas (Marathon) than at either end, and may be essentially ZERO. Note that “zero” to “zero to 3 mm” is a huge divide. 1.7/1.8 mm/year makes up the 8 inches per century figure, so it is a huge (“all of it” huge) difference.
We don’t know how much, if any, the sea is rising relative to the land at Key Biscayne. It has not been measured. We don’t know of whatever sea level rise we see there is caused by the sea coming up or the land going down, or a combination of land up or down, sea up or down.
The land area of Key Biscayne, however, has been demonstrated not to have changed since 1962 — though we are aware of massive human influence on that metric — influence to maintain it at its present size.
Bottom Line: The thing measured “Land Area of Key Biscayne” does not inform us of the facts regarding if Key Biscayne as “an island is sinking, vanishing or being washed away” due to Sea Level Rise. It only informs us of short-term historic land area of Key Biscayne == there is no discernible change in land area in the period 1962-2012 from any cause.
Current sea level rise does not register as eustatic sea level rise in geologic terms. You allude to this with questions of subsidence/uplift. If regional sea levels around the planet are dependent on regional subsidence/uplift and a universal eustatic sea level is not apparent everywhere, then there is said to be no global sea level change.
The oft mentioned 8 inches in 100 years has been masked by sedimentation and there is no major increased accommodation space or landward transgression of coast line with onlap of depositional sequences that I’m aware of. It’s been this way since the Younger Dryas ended, despite humans decreasing sediment supplies to coastlines.
If a measurable eustatic sea level rise were occurring then it wouldn’t matter how many truck loads of sand you brought in, the island would become inundated. Since 1962, if eustatic sea level rise were occurring like it was at the end of the last glacial period, sea level would have risen by 10 meters.
http://www.bioone.org/doi/abs/10.2112/JCOASTRES-D-12-00172.1?journalCode=coas
http://gradworks.umi.com/35/91/3591094.html
http://www.sciencedirect.com/science/article/pii/S0025322715000031
Reply to RWTurner ==> The recent long-term rise, as the single digit mm/yr rates (<5) is not likely to inundate tropical reef-based islands, unless they sink themselves through shoreline destructive shoreline modification, fresh water removal and reef destruction, or a combination of the three.
ONLY if water currently stored on land as ice is massively, rapidly returned to the seas will we see islands disappear due to sea level rise. The physics of doing that in the next century or two ?? Not likely.
Bottom of the Bottom Line…
“It only informs us of short-term historic land area of Key Biscayne == there is no discernible change in land area (or shape) in the period 1962-2012 from any cause.”
Therefore the Impact of Rising Sea Levels is not significant enough to be discernible on Key Biscayne.
Thanks, Kip Hansen. As a resident of Key Biscayne (since 1971), I care about this.
From Station 8723170: Miami Beach, FL (Mean Sea Level Trends, 1931 to 1981):
“The mean sea level trend is 2.39 millimeters/year with a 95% confidence interval of +/- 0.43 mm/yr based on monthly mean sea level data from 1931 to 1981 which is equivalent to a change of 0.78 feet in 100 years.” (0.3 meters = 1 foot)
See http://tidesandcurrents.noaa.gov/sltrends/sltrends_station.shtml?stnid=8723170
From Station 8724580: Key West, FL (Mean Sea Level Trends, since 1913):
“The mean sea level trend is 2.33 millimeters/year with a 95% confidence interval of +/- 0.15 mm/yr based on monthly mean sea level data from 1913 to 2014 which is equivalent to a change of 0.77 feet in 100 years.” (0.3 meters = 1 foot)
See http://tidesandcurrents.noaa.gov/sltrends/sltrends_station.shtml?stnid=8724580
We have a ground level garage that has always partially flooded something less than 1/2 inch during king tides.
Reply to Andres Valencia ==> As there is no official tide station at Key Biscayne, you are left to hoping that the measurements north and south of you can be “averaged”. Did you notice that this WOULD NOT WORK for Marathon? Marathon on the Tides and Currents map shows a 3-6 mm/yr rise. That is HIGHER than the rise south and north.
Anyway, it is not surprising that your garage floods at King Tide — given the average altitude of the island.
As David Middleton has pointed out, despite whatever relative sea level rise has been experienced, Key Biscayne hasn’t been inundated, or lost any land area, at least in the last 50 years.
As Kip Hansen pointed out, with a maximum elevation of ~5′ ASL, flooding during seasonal high tides isn’t surprising.
A photo of King Tide flooding in Miami was the sum total of AGW “evidence” presented by Sen. Bill Nelson at the recent Senate hearing.
The porous nature of the limestone bedrock coupled with a few inches of sea level rise certainly could accentuate King Tide flooding a bit.
Anyway, all this talk of territory lost to the waves is irrelevant.
Because, according to the pull-out feature in my copy of National Geographic we should all be able to move to a new verdant paradise on the shores of Antarctica and Greenland.
At least it looks green on the map that they provide of “if all the ice melted”.
Next month’s issue may like to consider the scenario – “if the ocean boiled off into space”.
Then, “if squid had evolved to become the dominant intelligent species on planet earth”.
What the crap are they going to come up with next?!!
Here it is. Here is the internet version.
What shall we call the newly formed rolling plains of East Antartica?
I would suggest that a good name would be, “la la land”.
The idiots at Nat Geo have already moved there. It seems:
http://ngm.nationalgeographic.com/2013/09/rising-seas/if-ice-melted-map
Although the text overlays my home here in Southern California, I don’t discern much change in the coastline. So, I guess we’re safe. My wife and I have been going down to the same beach regularly for the last 20 or so years. The high-tide line hasn’t moved, that I can tell, relative to the beach-front buildings. But my eyes probably wouldn’t discern a 20 – 30 mm rise in sea level over that time period.
Reply to Retired Engineer Jim ==> See the NOAA Tides and Currents Sea Level Trends map. For the most part, relative sea level in Southern California is trending, rising, at 0-3 mm/yr. Except for a single spot in Northern California, rising at 3-6 mm/yr, the NW US coast is either rising slightly at 0-3 mm/yr or SINKING at -6 to 0 mm/yr.
Now, just the fact that Relative Sea Level Rise (the important measure of sea level) can be negative in an entire US coastal region (NW US Pacific Coast) , while the worldwide Absolute Average Sea Level is rising (8 inches over the last century, and at 3.2 mm/yr the last decade or two) has to tell us something.
I think it tells us that there is a lot we don’t understand about sea levels and implications of this long slow rise over the last centuries.
“… a lot we don’t know …” covers it I believe. Taking historic geology we ran into the problem of how to interpret coastal changes and the process is as ugly as politics or making sausage. There are eustatic changes caused by volumetric changes in the amount of liquid on the planet (the end of the last ice age resulted in an eustatic rise of 100 meters or so). Then there are isostatic changes due to rebounding continental masses as they recover from the disappearance of immense amounts of ice, and other longer term processes such as continental drift and related changes in the surface topography of the planet which change the volumes and geometry of the major basins. There are also thermal changes that can lead to eustatic changes in volume.
Then there is simply what I think of as the “fog of research,” which is similar to the fog of war but with fewer bullets in the air. For instance, there is excellent geological evidence of a marine high stand of ca. 1.5 meters above the present mean sea level during the early Holocene global thermal maximum. Good evidence of this comes from such widely dispersed regions as Australia, Tasmanian, Micronesia, Brazil and Texas. But … there is no reported evidence of such a high stand along the west coast of North America. I’ve looked. There are a number of possibilities including a tectonic regime that is more active than we believe, or much greater coastal erosion. But the commonest response I have had is “it didn’t happen here.” Personally I believe we do have west coast evidence in the interior of Central California around the Sacramento – San Joaquin delta, but it will be nearly impossible to prove without some astonishing luck.
Well, obviously, you have not been standing perfectly still at high tide.
Most of the alarmist scenarios require that you stand perfectly still for several hundred years.
Then finally when the water is up to your knees, you will say “enough, I’m tired of this, already”.
And then you will become a displaced climate vagrant.
(erm… I mean migrant).
http://www.bc.edu/bc_org/avp/cas/fnart/fa267/boston/sequ_ani.gif
My home is just shy of 1200 feet elevation and the the land has not been turned to plow because of the underlying limestone, which is ancient seabed. How dense does one have to be to not grasp that there are forces at work on this planet much greater than a few ppm CO2?
In fact, the US has run a coastal survey since 1807 when Jefferson established the survey of the coast. There are very high accuracy maps that document most of coast of the continental US. These charts and maps were critical for establishing light houses and creating navigation charts. The United State Lighthouse Service later folded into the Coast Guard employed these maps in determining light house sites. The coastal survey is now administered by NOAA (shipping is critical to commerce.
Another way to test is to offer to buy up low island nations at a distressed rate per acre and see what the reaction is from the inhabitants. Throw in some reduced fee appearances from celebrities as a bonus. One reason they will not take the offer is because they know Richard Branson already bought up an island as a private resort after making appearances with Gore.
You’re children are being educated by socialists. They will “believe” believe me. Indoctrination.
Good idea! Let’s not forget that the oceans are deep and the image only shows the surface layer, to which satellite data contribute at most a fraction, if any useful information about the ocean interior at all. Oceans govern climate, but there’s a long way to understand climate: http://oceansgovernclimate.com/the-long-way-to-understand-climate/.
Or just check the Prices for Sea Front Property.
Ocean Bed Earthquakes making the land rise up out the sea
China has recently built several islands in the South China Sea.
I’m sure if the Micronesians ask nicely the UN will help them do the same thing.
Thanks, David Middleton.
What a surprise, to see “my” island in WUWT.
I found a FEMA flood map at http://msc.fema.gov/portal/search?AddressQuery=Key%20Biscayne%2C%20FL%2033149
Since 1971 there has been less than 1/2 inch of ground floor garage partial flooding during king tides, I can see no change, and I don’t plan to move out.
“The mean sea level trend is 2.39 millimeters/year with a 95% confidence interval of +/- 0.43 mm/yr based on monthly mean sea level data from 1931 to 1981 which is equivalent to a change of 0.78 feet in 100 years.” (0.3 meters = 1 foot)
From Station 8723170: Miami Beach, FL (Mean Sea Level Trends, 1931 to 1981):
http://tidesandcurrents.noaa.gov/sltrends/sltrends_station.shtml?stnid=8723170
“The mean sea level trend is 2.33 millimeters/year with a 95% confidence interval of +/- 0.15 mm/yr based on monthly mean sea level data from 1913 to 2014 which is equivalent to a change of 0.77 feet in 100 years.” (0.3 meters = 1 foot)
From Station 8724580: Key West, FL (Mean Sea Level Trends, since 1913):
http://tidesandcurrents.noaa.gov/sltrends/sltrends_station.shtml?stnid=8724580
2223 vs 2179 acres – that’s 2% *growth* in land area – near the uncertainty of ‘rough-and-ready’ planimery – certainly within the variability due to tides and storms.
With all due respect, I doubt these maps are that accurate.