Guest Post by Willis Eschenbach
Much has been written of late regarding the impending projected demise of the world’s coral atoll islands due to CO2-caused sea level rise. Micronesia is suing the Czech Government over CO2 emissions that they claim are damaging their coral atolls via sea level rise. Tuvalu and the Maldives are also repeating their claims of damage from CO2. If the sea level rises much, they say they will simply be swept away.
Recently, here in the Solomon Islands, the sea level rise has been blamed for saltwater intrusion into the subsurface “lens” of freshwater that forms under atolls. Beneath the surface of most atolls, there is a lens-shaped body of fresh water. The claim is that the rising sea levels are contaminating the freshwater lens with seawater. On other atolls, increased sea levels are claimed to be washing away parts of the atoll.
In this paper, I will discuss the two interrelated claims that people are making as illustrated above. The claims are:
1. Sea level rise causes salt water to intrude into the freshwater lens
2. Sea level rise gravely endangers low-lying coral atolls like Tuvalu, Kiribati, and the Maldives. A mere 1-meter rise would see them mostly washed away.
I will look at the real causes of the very real problems faced by atoll dwellers. Finally, I will list some practical measures to ameliorate those problems.
And before you ask, how do I know this atoll stuff? For three years I lived on and worked on and had wells dug on and watched the moon rise over and dived in the lagoon and on the reef wall of a coral atoll in the South Pacific … hey, somebody has to … that plus a lot of study and research.
Claim 1. Can a sea level rise cause salt water to intrude into the freshwater lens?
Short answer, no. To understand what is really happening with the freshwater lens, we’ll start with the geology. Here is a cross-section of a typical atoll that I drew up.
Figure 1. Typical cross section through a coral atoll. The living coral is in the ring between the dotted green line and the beach. The atoll used for the photo in this example is Tepoto Atoll, French Polynesia. Click image to embiggen.
Note that the seawater penetrates throughout the porous coral rubble base. Because fresh water is lighter than salt water, the freshwater lens is floating on this subsurface part of the ocean. The weight of the freshwater pushes down the surface of the seawater underneath it, forming the bottom of the “lens” shape. The lens is wider in areas where the atoll is wider. The amount of fresh water in the lens is a balance between what is added and what is withdrawn or lost. The lens is only replenished by rain.
The important thing here is that the freshwater lens is floating on the sea surface. It’s not like a well on land, with an underground freshwater source with a water-tight layer below it. There is no underground freshwater source on an atoll. It is just a bubble of water, a rain-filled lens floating on a seawater table in a porous coral rubble and sand substructure. If there is no rain, the freshwater will eventually slowly mix with the salt water and dissipate. When there is rain, you get a floating lens of fresh water, which goes up and down with the underlying seawater.
So the second claim, that a sea level rise can cause the sea water to intrude into the freshwater lens, is not true either. The freshwater lens floats on the seawater below. A rise in the sea level merely moves the lens upwards. It does not cause salt water to intrude into the lens.
Claim 2. Would a sea level rise gravely endanger low-lying coral atolls?
Regarding atolls and sea level rise, the most important fact was discovered by none other than Charles Darwin. He realized that coral atolls essentially “float” on the surface of the sea. When the sea rises, the atoll rises with it. They are not solid, like a rock island. They are a pile of sand and rubble. There is always material added and material being lost. Atolls exist in a delicate balance between new sand and coral rubble being added from the reef, and atoll sand and rubble being eroded by wind and wave back into the sea or into the lagoon. As sea level rises, the balance tips in favor of sand and rubble being added to the atoll. The result is that the atoll rises with the sea level.
Darwin’s discovery also explained why coral atolls occur in rings as in Fig. 2 above. They started as a circular inshore coral reef around a volcanic rock island. As the sea level rose (or equally, if the island sank), flooding more and more of the island, the coral grew upwards. Eventually, the island was drowned by the rising sea levels, and all that is left is the ring of reef and coral atolls.
Why don’t we see atolls getting fifty feet high? Wind erosion keeps atolls from getting too tall. Wind increases rapidly with distance above the ocean. The atolls simply cannot get taller. The sand at that elevation is blown away as fast as it is added. That’s why all atolls are so low-lying.
When the sea level rises, wind erosion decreases. The coral itself continues to grow upwards to match the sea level rise. Because the coral continues to flourish, the flow of sand and rubble onto the atoll continues, and with reduced wind erosion the atoll height increases by the amount of the sea level rise.
Since (as Darwin showed) atolls float up with the sea level, the idea that they will be buried by sea level rises is totally unfounded. Despite never being more than a few meters tall, they have survived a sea level rise of up to three hundred plus feet (call it a hundred meters) within the last twenty thousand years. Historically they have floated up higher than the peaks of drowned mountains.
So the third claim is not true either. Atolls are created by sea level rise, not destroyed by sea level rise.
What is the real cause of salt water in the lens?
Given that the saltwater intrusion can’t be a result of sea level rise (because the lens is floating), why is there saltwater in the islanders’ wells? Several factors affect this. First and foremost, the freshwater lens is a limited supply. As island populations increase, more and more water is drawn from the lens. The inevitable end of this is that the water in the wells gets saltier and saltier. This affects both wells and plants, which draw from the same lens. It also leads to unfounded claims that sea level rise is to blame.
The second reason for saltwater intrusion into the lens is a reduction in the amount of sand and rubble coming onto the atoll from the reef. When the balance between sand added and sand lost is disturbed, the atoll shrinks. When the atoll shrinks, the lens shrinks.
The third reason is that roads and airstrips and changes in land use and land cover has reduced the amount of rain making it to the lens. Less freshwater in, more saltwater in.
What is the real cause of loss of beach and atoll land?
An atoll is not solid ground. It is not a constant “thing” in the way a rock island is a thing. An atoll is a not-so-solid eddy in a river of sand and rubble. It is an ever-changing body constantly replenished by a (hopefully) unending stream of building materials. It is a process, not a solid object. On one side, healthy reefs plus beaked coral-grazing fish plus storms provide a continuous supply of coral sand and rubble. This sand and rubble are constantly being added to the atoll, making it larger. At the same time, coral sand and rubble are constantly being eaten away by waves and blown away by the wind. The shape of the atoll changes from season to season and from year to year. It builds up on this corner, and the sea washes away that corner.
So if the atoll is shrinking, there are only a few possibilities. Erosion may have increased. The supply of sand and rubble, the raw atoll construction materials, may have decreased. Currents may have changed from reef damage, dredging, or construction.
Water erosion and current changes are increased by anything that damages or changes the reef. That thin strip of living coral armor is all that stands between a pile of sand and the endless waves. When the reef changes, the atoll changes.
Erosion is also caused by a variety of human activities. Road and path building, house construction, ground cover change, clearing of channels through the reef, the list is long.
The reduction in the supply of coral sand and coral rubble, however, is harder to see. This reduction has two main causes – using of coral for building, and killing the wrong fish. The use of coral as a building material in many atolls is quite common. At times this is done in a way that damages the reef. Anything that affects the health of the reef affects how much atoll building material it produces each year. This is the somewhat visible part of the loss of building materials, the part we can see.
What goes unremarked is the loss of the reef sand, which is essential for the continued existence of the atoll. The major cause for the loss of sand is the indiscriminate, wholesale killing of parrotfish and other beaked reef-grazing fish. A single parrotfish, for example, creates around a hundred kilos of coral sand per year. Parrotfish and other beaked reef fish create the sand by grinding up the coral with their massive jaws and bony throats, digesting the food, and excreting the ground coral.
Beaked grazing fish are vital for overall coral health, growth, and production. This happens in the same way that pruning makes a tree send up lots of new shoots. The constant grazing by the beaked fish keeps the corals in full production mode. This greatly increases the annual production of coral for sand and rubble.
Unfortunately, these fish sleep at night, and thus are easily wiped out by night divers. The invention of the diving flashlight has meant that their populations have plummeted in many areas in recent years. Result? Less sand means less beaches, and means more claims of “CO2 is to blame, you can see the damage!”.
Some Practical Suggestions
What can be done to turn the situation around for the atolls? From the outside, not a whole lot. Stopping the Czechs from burning coal won’t do a damned thing. From the outside, we can offer only assistance. The work needs to occur on the atolls themselves.
There are, however, a number of low-cost, practical steps that atoll residents can take to preserve and build up their atolls and protect the freshwater lens. In no particular order, these are:
1. Stop having so many kids. An atoll has a limited supply of water. It cannot support an unlimited population. Enough said.
2. Catch every drop that falls. On the ground, build small dams in any watercourses to encourage the water to soak into the lens rather than run off to the ocean. Put water tanks under every roof. Dig “recharge wells”, which return filtered surface water to the lens in times of heavy rain. Catch the water off of the runways. On some atolls, they have put gutters on both sides of the airplane runway to catch all of the rainwater falling on the runway. It is collected and pumped into tanks. On other atolls, they let the rainwater just run off of the airstrip back into the ocean …
3. Conserve, conserve, conserve. Use seawater in place of fresh whenever possible. Use as little water as you can.
4. Make the killing of parrotfish and other beaked reef grazing fish tabu. Stop fishing them entirely. Make them protected species. The parrotfish should be the national bird of every atoll nation. I’m serious. If you call it the national bird, tourists will ask why a fish is the national bird, and you can explain to them how the parrotfish is the source of the beautiful beaches they are walking on, so they shouldn’t spear beaked reef fish or eat them. Stop killing the fish that make the very ground underfoot. The parrotfish and the other beaked reef-grazing fish are constantly building up the atoll. Every year they are providing tonnes and tonnes of fine white sand to keep the atoll afloat in turbulent times. They should be honored and protected, not killed. Caring for the reef is the single most important thing you can do.
5. Be cautious regarding the use of coral as a building material. The atoll will be affected if anything upsets that balance of sand added and sand lost. It will erode if the supply of coral sand and rubble per year starts dropping (say from reef damage or extensive coral mining or killing parrotfish) or if the total sand and rubble loss goes up (say by heavy rains or strong winds or human erosion or a change in currents).
So when coral is necessary for building, take it sparingly, in spots. Take dead or dying coral in preference to live coral. Mine the deeps and not the shallows. Use hand tools. Leave enough healthy reef around to reseed the area with new coral. A healthy reef is the factory that annually produces the tonnes and tonnes of building material that is absolutely necessary to keep the atoll afloat. You mess with it at your peril.
6. Reduce sand loss from the atoll in as many ways as possible. This can be done with plants to stop wind erosion. Don’t introduce plants for the purpose. Encourage and transplant the plants that already grow locally. Reducing water erosion also occurs with the small dams mentioned above, which will trap sand eroded by rainfall. Don’t overlook human erosion. Every step a person takes on an atoll pushes sand downhill, closer to returning to the sea. Lay down leaf mats where this is evident, wherever the path is wearing away. People wear a path, and soon it is lower than the surrounding ground. When it rains, it becomes a small watercourse. Invisibly, the water washes the precious sand into the ocean. Invisibly, the wind blows the ground out from underfoot. Protect the island from erosion. Stop it from being washed and blown away.
7. Monitor and build up the health of the reef. You and you alone are responsible for the well-being of the amazing underwater fish-tended coral factory that year after year keeps your atoll from disappearing. Coral reseeding programs done by schools have been very successful. Get the kids involved in watching and recording and photographing the reef. Remind the people that they are the guardians of the reef. Talk to the fishermen.
8. Expand the atoll. Modern coastal engineering has shown that it is often quite possible to “grow” an atoll. The key is to slow down the water as it passes by. The slower the water moves, the more sand drops out to the bottom. Slowing the water is accomplished by building low underwater walls perpendicular to the coastline. These start abovewater, and run out until the ends are a few metres underwater. Commercially this is done with a geotextile fabric tubes which are pumped full of concrete. See the references for more information. In the atolls the similar effect can be obtained with “gabbions”, wire cages filled with blocks of dead coral. Wire all of the wire cages securely together in a triangular pattern, stake them down with rebar, wait for the sand to fill in. It might be possible to do it with old tires, fastened together, with chunks of coral piled on top of them. It will likely take a few years to fill in. This triangular shape does not attempt to stop the water currents. Think of it as a speed bunp. It just slows the currents down and directs them toward the beach to deposit their load of sand. Eventually, the entire area fills in with sand.
Of course to do that, you absolutely have to have a constant source of sand and rubble … like for example a healthy reef with lots of parrotfish. That’s why I said above that the most important thing is to protect the fish and the reef. If you have a healthy reef, you’ll have plenty of sand and rubble to keep the atoll afloat forever. If you don’t, you’re in trouble.
Coral atolls have proven over thousands of years that, if left alone, they can go up with the sea level. And if we follow some simple conservation practices, they can continue to do so and to support atoll residents.
But they cannot survive an unlimited population increase, or unrestricted overfishing, or overpumping the water lens, or unrestrained coral mining. Those are what is killing the atolls, not the same rate of sea level rise that we’ve had for the last hundred years.
FURTHER REFERENCES:
On global sea level rise levelling off: University of Colorado at Boulder Sea Level Change, http://sealevel.colorado.edu
On Darwin’s discovery: Darwin, C., The Autobiography of Charles Darwin 1809-1882, 1887
“No other work of mine was begun in so deductive a spirit as this; for the whole theory was thought out on the west coast of S. America before I had seen a true coral reef. I had therefore only to verify and extend my views by a careful examination of living reefs. But it should be observed that I had during the two previous years been incessantly attending to the effects on the shores of S. America of the intermittent elevation of the land, together with the denudation and deposition of sediment. This necessarily led me to reflect much on the effects of subsidence, and it was easy to replace in imagination the continued deposition of sediment by the upward growth of coral. To do this was to form my theory of the formation of barrier-reefs and atolls.” (Darwin, 1887, p. 98, 99)
On the results of coral mining and changing the reef: Xue, C. (1996) Coastal Erosion And Management Of Amatuku Island, Funafuti Atoll, Tuvalu, 1996, South Pacific Applied Geoscience Commission (SOPAC), http://conf.sopac.org/virlib/TR/TR0234.pdf This atoll was cited by the Sierra Club as an example of the dangers of sea level rise. The truth is more prosaic.
On the same topic: Xue, C., Malologa, F. (1995) Coastal sedimentation and coastal management of Fongafale, Funafuti, Tuvalu, SOPAC Technical Report 221
More information on how parrotfish increase reef production: http://www.esajournals.org/doi/abs/10.1890/1051-0761(2006)016%5B0747:TIOEGS%5D2.0.CO%3B2
On the cause of erosion in Tuvalu: Tuvalu Not Experiencing Increased Sea Level Rise, Willis Eschenbach, Energy & Environment, Volume 15, Number 3, 1 July 2004 , pp. 527-543, available here (PDF doc).
On expanding island beaches: Holmberg Technologies, http://www.erosion.com/
On the atolls getting larger: Global-scale changes in the area of atoll islands during the 21st century
On the dangers of overpopulation: Just look around you …
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[UPDATE June 3, 2010] Other scientists are catching up with me (emphasis mine).
Global and Planetary Change, Article in Press, Accepted Manuscript, doi:10.1016/j.gloplacha.2010.05.003
The dynamic response of reef islands to sea level rise: evidence from multi-decadal analysis of island change in the central pacific
Arthur P. Webb a, and Paul S. Kench b; a South Pacific Applied Geoscience Commission, SOPAC. Fiji; b School of Environment, The University of Auckland, Private Bag 92019, Auckland, New Zealand
Received 22 February 2010; accepted 13 May 2010. Available online 21 May 2010.
Abstract
Low-lying atoll islands are widely perceived to erode in response to measured and future sea level rise. Using historical aerial photography and satellite images this study presents the first quantitative analysis of physical changes in 27 atoll islands in the central Pacific over a 19 to 61 year period. This period of analysis corresponds with instrumental records that show a rate of sea level rise of 2.0 mm.y-1 in the Pacific.
Results show that 86% of islands remained stable (43%) or increased in area (43%) over the timeframe of analysis. Largest decadal rates of increase in island area range between 0.1 to 5.6 hectares. Only 14% of study islands exhibited a net reduction in island area.
Despite small net changes in area, islands exhibited larger gross changes. This was expressed as changes in the planform configuration and position of islands on reef platforms. Modes of island change included: ocean shoreline displacement toward the lagoon; lagoon shoreline progradation; and, extension of the ends of elongate islands. Collectively these adjustments represent net lagoonward migration of islands in 65% of cases.
Results contradict existing paradigms of island response and have significant implications for the consideration of island stability under ongoing sea level rise in the central Pacific.
First, islands are geomorphologically persistent features on atoll reef platforms and can increase in island area despite sea level change.
Second; islands are dynamic landforms that undergo a range of physical adjustments in responses to changing boundary conditions, of which sea level is just one factor.
Third, erosion of island shorelines must be reconsidered in the context of physical adjustments of the entire island shoreline as erosion may be balanced by progradation on other sectors of shorelines. Results indicate that the style and magnitude of geomorphic change will vary between islands. Therefore, Island nations must place a high priority on resolving the precise styles and rates of change that will occur over the next century and reconsider the implications for adaption.
In other words, the islands are floating upwards with the sea level rise, just as I had said. So for those in the comments section who think I’m just making this up … think again. In particular, the final comment by lkrndu22 says that I am “hoist by my own petard” because ocean acidification has already caused “evident and severe” damage … ‘fraid not. The islands continue to rise. The main cause of damage to the corals is … coral mining and killing the fish. And islands where that is happening are in danger, as I indicated above.
But sea level rise? The atolls have lived through that for thousands of years without damage.
Cement a friend (03:07:47)
I couldn’t find the “detailed graph on Tuvalu” which showed no sea level rise since 1998. Page number? Figure number?
Let me use this as a call for better citation habits. It drives me mad when someone says “it’s shown in the IPCC report” … well yeah, but where? Please let us know what figure or what page and what paragraph you are talking about.
Would it not be easier to just determine where these atolls lie along tectonic plate edges in order to determine if their ultimate fate is to rise or fall below the surrounding sea level? If the old volcanic mountain an atoll sits upon is about to sink beneath the encroaching plate, the future is a done deal. Move to another island. By the way, love the stretch marks on ol’ mother nature’s skin beneath the Atlantic ocean.
Willis – great post and one that succinctly describes the process that was once taught in physical geography at school. Little wonder that Australian sceptics are described as “well funded unemployed” – they are old enough to have been educated before post modernism encouraged critical thinking without basic principles. Introducing a few lessons about parrot fish and symbiosis would be a good start. btw does coral “sand” have a lower density than rock formed beach sand? I was pondering that if so, it may be more susceptible to erosion.
Evan – your mod comment “follow the money” pretty much sums up the island style / third world attitude to exploiting the financial opportunities/benefits presented by a pro-AGW view.
Now we need is a post on “floating river deltas” to explain that a billion people won’t drown at 3mm/year of sea level rise whilst rivers keep flowing to the sea but living on a flood plain does pose risks such as say maybe …. flooding.
As my final comment – many Pacific Islanders enjoy the comforts of home in New Zealand and Australia where they make a valuable contibution to the community (and the odd great sportsperson) and also provide financial support to extended family back on the islands.
Craigo (20:10:47)
Good question, I hadn’t thought about that. Coral sand is something like 95% calcium carbonate, density ~2.7. Beach sand is generally quartz, density ~2.6. So I don’t think the density makes a difference.
Coral sand, however, is very much softer than quartz (3 on the Mohs scale, compared to 7 for quartz). As a result, the grains tend to be more rounded than the angular grains of quartz sand. I suspect this round shape may make them more susceptible to erosion, but I don’t know that.
There’s some interesting photos here.
Willis, you have reminded me of the ceramic strike plates we used in college geology class. Loved that class. Been a rock hound ever since.
I have plowed (well, I sat on the cat while my boyfriend plowed) what is called sugar snow. This snow is cold, hard, and in the shape of little round seed beads. It is just like trying to plow dry sugar. As soon as the cat plowed the snow off to the side, it fell right back into the roadbed. When rain hits it, there is no slick surface for drainage. The rain works right through it. So yes, I would imagine that rounded sand would erode much faster as there is no way for the sand to matrix together, forming a more resistant interconnected surface against rain and wind erosion.
Craigo (20:10:47), you also say:
referring to the comment:
While I agree that the islanders are looking to get some easy money, I don’t fault them for that in the least. If you live on a strip of sand that is 500 metres long, 15 metres wide, and one metre tall, and your island gets visited by a boat every couple months, the money making opportunities are … well … somewhat scarce.
So I’d likely do the same, nothing to lose. Why not sue the Czechs, especially if someone else is picking up the court costs? Where’s the downside?
[REPLY – Hmm. Maybe we could find a more efficient means of transfer? Cargo cults are cheaper than carbon cults. ~ Evan]
Sorry Willis,
I am am not used to blogs
Here is what I said above
“Willis and Vincent,
The latest (to Jun2009) South Pacific report is here http://www.bom.gov.au/oceanography/projects/spslcmp/reports_6mths.shtml
It is worth downloading for anyone interested in climate cycles.” The report is 37pages and over 3MB to download
I earlier said it was graph 10, and its on Page 21
I tried to copy part of the graph a couple of ways including the Printkey program. How does one get a small picture into the comment? I know nothing about uploading and I am still thinking about a website.
In 1998 there was a huge drop in sea level of about 0.4m for almost the whole year. Maybe this is affecting the supposed trend. Maybe you could explain it.
Nesting like Climate Audit could make it easier to follow a thread.
The myth of drowning atolls clearly shows the myriad problems of blaming everything on CO2. The main issue is that if we say “it’s CO2”, it stops us from finding or working on the real problems.
Another ever present issue is certainly “cui bono”. Or follow the money, as you say.
The third problem is the loss of credibility of the environmental movement. This is not some island-hatched scheme. From the Sierra Club’s initial articles to the Greenpeace backing of the whole Tuvalu campaign, it’s all happened through the intervention of once-respected environmental organizations. The worst is that it sets the environmental movement up once again as the “boy who cried wolf”.
Following on the Club of Rome and Paul Ehrlich’s “population bomb” and other doomsday claims, this is not good news. There’s still a host of real environmental issues that need addressing.
Great post, thanks Willis. What are housing prices like down there. I’ve had enough of cold rainy England!
No Sea Level Threat to Maldives
(11 Jan 04)
In a recent paper, Nils-Axel Mörner et al report on a new study of sea levels in the Maldives, a coral atoll group in the centre of the Indian Ocean and inhabited for the last 1,500 years.
They found that sea levels over the last few thousand years has at times been higher than those of today with no recent tendency toward sea level rise. See past sea level history:
The above from the late John L Dalys site here
How do I post a graph? assuming it’s possible
tallbloke (00:16:42) :
“Great post, thanks Willis. What are housing prices like down there. I’ve had enough of cold rainy England!”
Good idea TB. I too am fed up of grey sky’s, cold, snow and rain. I’m off to southern Spain in a few weeks time to remind myself what the sun looks like!
Here is a sample of sea level as observed 1841-2004
The 1841 sea level benchmark (centre) on the `Isle of the Dead’, Tasmania. According to Antarctic explorer, Capt. Sir James Clark Ross, it marked mean sea level in 1841. Photo taken at low tide 20 Jan 2004.
Mark is 50 cm across; tidal range is less than a metre. © John L. Daly.
link
The Maldives have been at it for a while now.
Maldives Joins the Frenzy (19 May 03)
For several years, the government of Tuvalu, egged on by GreenPeace activists, has led the international campaign over the `plight’ of coral island nations like Tuvalu, warning they could sink below the waves due to `global warming’.
As shown further below on this page, that claim is both nonsense and spurious – there has been no rising seas at Tuvalu, just a rise in political noise.
Now the Maldives has joined in. They too claim to be in danger of rising seas. Yet, incredibly, their President Maumoon Abdul Gayoom has admitted –
“We are monitoring sea level rises in the Maldives and so far there is no established proof that there is a rise,” he said. “But that does not mean that it is not happening.”
So, he cannot find any evidence of sea level rise in his own home turf, but still thinks it might be happening anyway.
And he expects public policy in major economies to be determined by what he thinks but for which he has no evidence?
Gayoom claims to be taking the advice of `scientists’, but the President of INQUA, the international commission with expertise in sea level, Nils-Axel- Mörner, had this to say recently –
“It has been popular to threaten small islands and low-lying coasts with scenarios of disastrous future flooding. The Maldives has been the most utilised target. We have undertaken a careful analysis of actual sea level changes in the Maldives. No rise has been recorded either in the present or the past centuries. Instead we have documented a significant sea level fall in the last 20-30 years.” – Nils-Axel Mörner (President of INQUA)
Could it be that the real agenda for the Maldives is the same as that of Tuvalu – money compensation? Compensation for an imagined loss that has not happened, is not happening, but `might’ happen sometime in the unspecified future?
The above from here J L Daly site
Niels Axel Moerner was the president (1999-2003)
of the INQUA Commission on Sea Level Changes and
Coastal Evolution, and leader of the Maldives Sea Level Project.
Niels Axel Moerner on sea-level:
http://www.climatechangefacts.info/ClimateChangeDocuments/NilsAxelMornerinterview.pdf
1) Stone fences can act like snow fences and provide a resting place for wind blown sand.
2) As has been found in Turkey, stones on the ground can also reduce water evaporation from the surface.
3) Electro deposition of calcium can be used to create shaped “rocks” for special purposes. The size limits are larger than the local ability to move the created artifact.
Phillep Harding (12:21:32) : edit
All the kind of things that the folks on atolls need to protect their atolls. Low cost, and made out of local materials.
Regarding your third comment, the use of electricity to make artificial coral reefs has received wide attention, but I don’t think it has been used yet to create the type of underwater “speed bumps” needed to expand an atoll. It would be an excellent solution in combination with the gabbions I discussed above. There’s a description at the bottom of the page here.
Thanks,
w.
Willis. my Pacific Island Report at
http://nzclimatescience.net/images/PDFs/spsl3.pdf
is fully referenced. The Tuvalu results are Figure 13 on page 15. It is copied from the official Tuvalu report at
http://www.bom.gov.au/ntc/IDO60033/IDO60033.2007.pdf
where it is Figure 15 on page 27.
There is no change in sea level on Tuvalu.
I dislike the use of :’linear trends” as a way of studying climate data. The data are never uniform, they possess fluctuations on different scales which are deliberately concealed a trealistic estimate of the accuracy of such trends is never provided.and their values always depend on arbitrary choice of beginning and end points
The Latest Pacific Island Report is December 2009 at http://www.bom.gov.au/ntc/IDO60101/IDO60101.200912.pdf
No change at Tuvalu since 1998, see Figure 11
Vincent Gray (16:20:24)
Vincent, I agree about linear trend lines, which is why I generally only use them in conjunction with gaussian averages as in Figure 1 above.
However, I disagree that Fig. 15, p. 27 of the Tuvalu report, entitled “Monthly sea level at Funafuti SEAFRAME gauge”, shows that there is no sea level rise. You simply cannot decide that by looking at the raw data.
It would seem simple to determine whether the mean sea level (MSL), the average height of the sea, is rising or falling in Tuvalu. However, the measurement of the MSL at any given location is complicated by a number of factors:
1. Tidal oscillations, caused by the gravitational pull of the moon and the sun, cause changes in sea level with a major period from 12 to 24 hours, but which also have longer periods ranging up to half a century or more.
2. Barometric pressure changes from weather systems depress or increase sea levels, with time scales from hours to weeks.
3. The “El Nino” effect, on a time scale of years, strongly affects sea levels in the South Pacific.
4. Winds can cause the oceans to pile up against the land or push them away from the shore, on the time scale of hours to weeks.
5 Seasonal barometric variations have the same effect as those due to weather systems, on the scale of months.
6. The “sloshing” of tides, especially in enclosed basins such as atoll lagoons, can increase or decrease sea levels on a time scale of days to years, depending on the size of the basin.
7. Changes in seawater temperature, on a time scale from years to centuries, can increase or decrease sea levels.
8. The land on which the tide gauge is situated may be rising or falling.
Because of these difficulties, a very long record of tides is necessary to determine whether the MSL is rising or falling at a given location. Douglas (2001) argues that a record of 50 to 80 years is required to give a meaningful estimate of the change in sea level. This estimate is supported by the results of the “asymptotic analysis” method of Mitchell et. al. (2000), which show a +/- 1 mm error after 50 to 60 years.
Such an “asymptotic analysis” is actually done by the people in the work you cited. This method is shown in Fig.4, p.9 of the report you cited.Their conclusion is as follows:
So I fear that I must disagree with you. The sea level in Tuvalu is indeed rising overall, albeit with a very wide CI. Of course, because of the tidal cycles, any given short timespan may show a decrease. However, this is meaningless in determining whether the sea level is rising in the longer term.
All the best,
w.
Fascinating article Willis, as always. I think it would be a very simple matter to debunk the hysterical warmists if one could provide hard evidence that the atolls have survived sea level rises far greater than the IPCC projects during the end of the last ice age; how old are the atolls anyway?
You make a good point about the population carrying capacity of an atoll which is what a true environmentalist would be pointing out rather than the false blaming of CO2 which the watermelon groups do.
As I was reading your article it suddenly occurred to me that the way to deal with the effect of humans on atolls would be to create floating structures around the atoll and move the majority of the population there. Of course Wesley Bruce beat me to it and the seasteading site is very interesting and hopefully I’ll see some major progress in this area during my lifetime. If we’re going to spend tens of billions to alleviate the self-induced plight of the atoll dwellers, I’d much rather have the money spent on research into huge floating structures which could eventually become artificial islands and lead to humans being able to live anywhere on the ocean-covered part of the planet.
This is in line with Bjorn Lomberg’s calculations in The Skeptical Environmentalist. Even if the worst case IPCC scenarios of sea level rise were to occur it would be far simpler to deal with them by maintaining economic growth at the same rate it is currently occurring in which case we can afford to deal with the worst case future scenarios easily. If we instead follow the deindustrialization path proposed by the warmists, we shrink GDP and would be completely unable to afford to deal with environmental catastrophes.
Having had experience with Greenpeace types when I lived in Vancouver I find it laughable that they call themselves “ecologists”. The study of ecology requires the understanding of a vast number of feedback loops and lots of mathematics Most of the greenpeace types are basically innumerate and mention the Lotka-Volterra equation to them and one gets blank stares. They seem to be unable to grasp that ecology, like climate constantly changes and there are oscillations, chaotic behavior and, rarely, static behavior. They are technophobes and seek to destroy modern society. If the majority of people became aware of their true goals they’d get the same reception as a convicted pedophile at a daycare center.
But Progressives have taught islanders their Marxism. Act like victims, pick a target, freeze it, polarize it, and ask for “rich” nations to bail you out. In exchange, their delegations vote as told on NGO panels. A large part of what makes Obama tick, is the island mentality.
Boris Gimbarzevsky (03:02:52)
Boris, a good question. Here’s the usual fount of misinformation (Wikipedia) on the subject:
So the Great Barrier Reef has survived what is called the “Holocene trangression”, the huge rise in sea level during the end of the last glacial period.
Sea level rise during that period was quite large, viz(pdf, Science Magazine, subscription)
From this it is clear that the existing atolls can sustain anything that warming is likely to throw at them. Even in the extremely unlikely event that the current rate of rise were to triple, that is still less than the reefs have sustained in the past.
Tenuc (07:54:28) : I’m off to southern Spain in a few weeks time to remind myself what the sun looks like!
Bad news, Tenuc. I understand the Spanish government has banned the use of the sun for either cosmetic or comfort uses. It may only be harvested for generation of energy.
p.s. The new solar cell cloaks are quite cool; but it’s hell towing the transmission wires that lead back to the distributing utility everywhere you go…
Ah! @ur momisugly Roger Carr, if only Nicola Tesla had lived another decade…and realized his hunch about transmitting electricity without wires…