Anthony commented yesterday on the question of atolls and sea level rise here, and I had previously written on the subject in my post “Floating Islands“. However, Anthony referenced a paper which was incorrectly linked by New Scientist. So I thought I’d provide some more information on the actual study, entitled “The dynamic response of reef islands to sea level rise: evidence from multi-decadal analysis of island change in the central pacific”, by Arthur Webb and Paul Kench.
One of the ironies of the new paper involves the atoll of Amatuku in the island nation of Tuvalu. Amatuku became the first poster child of “drowning atolls” due to an article in the July/August 2003 issue of Sierra Magazine, the magazine of the Sierra Club. The article was entitled “High Tide in Tuvalu”, with the sub-title “In the tropical Pacific, climate change threatens to create a real-life Atlantis.” Here’s a recent photo of “Atlantis”:
Figure 1. Photo taken in the South Pacific nation of Tuvalu (8°S, 179°E), showing Amatuku Atoll and the abandoned causeway. PHOTO SOURCE
In the Sierra Magazine article the author described the terrifying effects of “global warming” on Amatuku Atoll, site of the Tuvalu Maritime Training Institute:
To explain global warming in stark detail, all Tito Tapungao has to do is show a visitor around the grounds of his school. Dressed in his sailor’s pressed whites, the chief executive officer of the Tuvalu Maritime Training Institute points out a small brick cabin built by missionaries in 1903. Now, a century later, annual high tides rise halfway up the bedposts.
YIKES! Be very afraid. So what is the irony in the new study?
Well, I’ll get to that. But first, a bit of history. The Sierra Magazine article was what impelled me to write my 2004 paper (Word Doc) on Tuvalu. I read that article, and my urban legend detector started ringing like crazy. Consider: the missionaries’ cabin was likely built a metre or so above high tide. Add another half metre for the floor, and a half metre to get “halfway up the bedposts” … no way, I thought, that the sea level has risen two metres in Tuvalu.
Upon further investigation, I found out that the answer was already known, because geologists had studied (pdf) the area. They found the changes in the shape of Amatuku Atoll were a result of changing currents from major alterations made in the reef during World War Two. A channel was cut from the lagoon to Amatuku, and a causeway was constructed between Amatuku and nearby Malitefale Atoll. Fill to make the causeway came from “borrow pits”, holes dug in the reef flats to provide coral rubble for the construction. And some decades after the war, further borrow pits were dug to provide building materials for the Maritime Institute. The swimmers in the Fig. 1 are swimming in one of the old borrow pits. Here’s an aerial view of the changes:
Figure 2. Amatuku and Malitefale Atolls, Tuvalu, South Pacific. Amatuku is less than a kilometre long.
As you can see, the changes in the reef structure were quite extensive. All of these alterations in the reef changed the currents around the two atolls. And of course, as a result, the shape of the atolls changed. This change in shape is to be expected – after all, atolls are just piles of sand and rubble in the middle of a wild ocean. One of the results was the erosion (not from CO2, not from warming, not from sea level rise, but erosion from man-made changes in the reef) of the corner of the atoll where the missionaries’ cabin was located.
Over the years since I published my paper, I’ve taken a lot of heat for my claims. I’ve gotten plenty of irate emails from folks in Tuvalu and around the world, emails castigating me for suggesting that the rising sea levels won’t drown the atolls, emails impugning my ancestry, emails saying we’d soon see thousands of “climate refugees” from Tuvalu, emails proposing that I perform anatomically implausible acts of sexual auto-congress, and mostly emails saying that I was clearly wrong, that it was patently obvious that rising sea levels would inevitably drown the atolls, duh, so there.
OK, enough history. I got a pre-publication copy of the current paper under discussion from one of my secret underground (underwater?) sources, my thanks to WS. The abstract of the paper says (emphasis mine):
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.
Ahhh, vindication is sweet. The authors agreed totally with what I had written in 2004. Rising sea levels don’t destroy atolls, and their shape is always changing. Exactly what I had taken so much heat for saying.
In addition to the Abstract, the Conclusions of the paper are quite interesting. Here are some extracts (emphasis mine):
Conclusions
The future persistence of low-lying reef islands has been the subject of considerable international concern and scientific debate. Current rates of sea level rise are widely believed to have destabilised islands promoting widespread erosion and threatening the existence of atoll nations. This study presents analysis of the physical change in 27 atoll islands located in the central Pacific Ocean over the past 20 to 60 years, a period over which instrumental records indicate an increase in sea level of the order of 2.0 mm y-1.
The results show that island area has remained largely stable or increased over the timeframe of analysis. Forty-three percent of islands increased in area by more than 3% with the largest increases of 30% on Betio (Tarawa atoll) and 28.3% on Funamanu (Funafuti atoll [the main atoll in Tuvalu – w.]). There is no evidence of large scale reduction in island area despite the upward trend in sea level. Consequently, islands have predominantly been persistent or expanded in area on atoll rims for the past 20 to 60 years.
… Results of this study contradict widespread perceptions that all reef islands are eroding in response to recent sea level rise. Importantly, the results suggest that reef islands are geomorphically resilient landforms that thus far have predominantly remained static or grown in area over the last 20 – 60 years. Given this positive trend, reef islands may not disappear from atoll rims and other coral reefs in the near-future as speculated. However, islands will undergo continued geomorphic change. Based on the evidence presented in this study it can be expected that the pace of geomorphic change may increase with future accelerated sea level rise. Results do not suggest that erosion will not occur. Indeed, as found in 15% of the islands in this study, erosion may occur on some islands. Rather, island erosion should be considered as one of a spectrum of geomorphic changes that have been highlighted in this study and which also include: lagoon shoreline progradation; island migration on reef platforms; island expansion and island extension. The specific mode and magnitude of geomorphic change is likely to vary between islands. Therefore, island nations must better understand the pace and diversity of island morphological change and consider the implications of island persistence and morphodynamics for future adaptation.
Couldn’t say it better myself … and oh, yeah, what about the irony?
Well, Amatuku, the poster child of disappearing atolls, the threatened “real-life Atlantis”, home of the disappearing missionaries’ cabin, happened to be one of the atolls considered in the study. The authors found that despite the loss of the missionaries’ cabin, Amatuku increased in area by about 5% over the nineteen year period during which it was studied … ah, the irony, it burns.
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Former BBC science editor Dr David Whitehouse comments on sea level rise from satellites:
http://www.thegwpf.org/the-observatory/580-sea-level-shenanigans.html
“Satellite data yields about 3.2 mm per year or about double that of the Tidal Gauges.
There could be many reasons for this. Either the Tidal or the satellite data could be subject to a bias, or they could be measuring different things (the satellites sending back global data are restricted to latitudes no greater than 66 degrees for example). Given the complex steps required to calibrate satellite data and convert it into sea level readings there is much scope for unrecognised errors.
It would be too much of a coincidence to postulate that the rate of increase in sea level had doubled at the same time that a new way was used to measure it! Whatever the situation, the two data sets show continuing sea level rise but the rate of that rise is incompatible between them and nobody has provided a convincing answer why this should be so.This means that the satellite data do not provide evidence that the rate of sea level rise has been accelerating. Additionally, there is no evidence of any change in the rate of sea level rise over the period of the 1992 – 2010 satellite data.”
As usual, this is something that John Daly had addressed:
http://www.john-daly.com/altimetry/topex.htm
“The T/P satellite cannot measure sea level when there is any land within the footprint because T/P cannot tell the land echoes from the sea echoes and gives a false result. This means that all sea areas within 3 to 5 kilometres of continental coasts, islands, even atolls, are not covered. Also not covered is all oceanic area north of 66°N or south of 66°S, due to the angled track of the satellite. This results in the Arctic Ocean and the high-latitude part of the North Atlantic being excluded. Also excluded is much of the oceanic area surrounding Antarctica. In areas with a large density of islands such as the Indonesian archipelago or the West Indies, the `no-go’ area several kilometres around each island will result in a substantial area of ocean being excluded from sea level measurement altogether.”
He is backed up by the The Australian Sea Frame project, http://www.bom.gov.au/ntc/IDO60033/IDO60033.2008.pdf, which comments:
“Satellite altimeters have an accuracy of several centimetres in the deep ocean, but are known to be inaccurate in shallow coastal regions. As such they cannot replace in-situ tide gauges. Tide gauges are needed to calibrate the satellite altimeters and provide accurate and more frequent sea level measurements in specific locations where reliable tide predictions and real time monitoring of extreme sea levels is of prime importance.”
The Sea Frame project shows there is no accelerating sea level rise although there is a short term trend of 5mm/year at Tuvalu. This is seized upon and extrapolated to claim there is a major problem when in fact most of this is a return to normality from the 97/98 El Nino.
“Tuvaluans are accustomed to the annual peaks, which bring well-documented flooding throughout the low-lying atoll nation. In the past decade or so, as our understanding of El Niño has improved, they also have come to expect lower sea levels during such events.”
“Although sea levels in the Tuvalu region normally fall in response to El Niño, the decrease that occurred during 1997/1998 El Niño can be considered extraordinary. Sea levels were lowered by 35 cm in March and April of 1998. By November 1998, sea level had completely recovered. Following the El Niño, the sea level resumed its normal seasonal cycle.”
“Sea levels reached 3.33m in March 1997 as a result of Tropical Cyclone Gavin, but the maximum sea level recorded over the duration of the record is 3.44 m on 28th of February 2006. This was not caused by a tropical cyclone, but was due to the highest predicted astronomical tide for several decades (3.24m) combined with a sea level anomaly of 0.2m due to the regional climate activity.”
This “King Tide” event brought journalists from all over the world to film Tuvaluans wading through waste deep water and recounting their tales of “highest in living memory”. No doubt the islanders did quite well out of these foolish doom seekers attending a natural event.
However,
“Sea level in the Pacific Forum region undergoes large inter-annual and decadal variations due to dynamic oceanographic and climatic effects such as El Niño. Such variability or ‘noise’ affects estimates of the underlying long-term trend. In general, more precise sea level trend estimates are obtained from longer sea level records as is shown in Figure 6. Sea level records of less than 25 years are thought to be too short for obtaining reliable sea level trend estimates. A confidence interval or precision of 1 mm/year should be obtainable at most stations with 50-60 years of data on average, providing there is no acceleration in sea level change, vertical motion of the tide gauge, or abrupt shifts in trend due to tectonic events.”
The mean trend for datasets that span more than 25 years is 1.3 mm/yr.
Data from JASL as at June 2009
It is interesting to go through the National Adaptation Plans of Action (NAPAs), Nationally Appropriate Mitigation Actions (MAMAs) and various other Strategies for Resilience produced by low-lying island states and Bangladesh because the governments involved are not signalling large scale population displacement or the need for relocation as a result of sea level rise or salinisation. And yet the Western donor governments, who are signing MoUs with these governments to fund adaptation and mitigation, continue to say that one of the most pressing threats is the inundation of islands making them uninhabitable and creating “climate refugees”. Who is right? And what time scale are we talking about? Willis tells us not to worry about a one-third metre rise in sea levels this century. Others say this will be catastrophic. Willis argues that a 30cm rise is unexceptional, but is he also saying that such a rise will make islands uninhabitable, that gradually populations will drift away (humans have always used migration to cope with a changing environment and governments mostly get in the way of this process) and we must simply live with this Pacific island depopulation? Or is he saying something different – that islands will adapt to rising seas, adding more coral sand, and human populations will aid this by using fresh water more sensibly, they will learn to better protect the corals, fish less, import food etc and populations will essentially remain as they are?
I undertook geological research on Tuvalu in the eighties. At the time I was heavily into guano! I have published on some effects of WWII on Amatuku.
There are a couple of other ironies that can be added to that of Willis. Arthur Webb and Paul Kench have to a great extent rediscovered the wheel. Back in 1973 a major hurricane, Bebe, swept Fongafale, the main islet of Funafuti, the principal atoll of Tuvalu. In one night the area of that islet increased by 15% as a vast hurricane bank of debris was piled up on the windward side by the storm. This is part of the normal aggradation process whereby atolls grow. It has been documented for many years. On the landward side of the new bank on Fongafale are fossil debris banks from previous savage storms. One cemented by natural means now protects the airstrip from modern storms. The 1973 bank and the growth process on Fongafale were studied in depth by Professor Roger McClean, at the time researcher at the University of Auckland – from whence comes the new study. Roger had extensive funding from, of all places, the UN.
And, if any of researchers of the 21st century were to get from the shelves of their libraries a book published in the nineteenth century entitled “Coral Reefs” by one C. Darwin, they would find the processes of atoll origins and growth described therein. Oddly enough Darwin’s ideas precipitated as savage and as unpleasant a debate as the present AGW debacle.
What goeth around cometh around.
The story has got a mention in one of the UK newspapers:
http://www.dailymail.co.uk/sciencetech/article-1283669/Low-lying-Pacific-islands-growing-sinking-sea-levels-rise.html
And the Daily Telegraph also has it:
http://www.telegraph.co.uk/news/worldnews/australiaandthepacific/tuvalu/7799503/Pacific-islands-growing-not-shrinking-due-to-climate-change.html
Daily Telegraph even! Mod: please edit!
[I’m not a mod, but I fixed it – w]
It is interesting to note that the BBC is claiming that although the islands are becoming bigger, climate change may make them uninhabitable. It is not clear where they sourced this statement or on what basis it was made.
The issue that is raised here is the question of land area vs. sea level rise. Many of the studies make preposterous claims for the accuracy of sea level rise that are simply not valid in terms of the instruments being used to make the measurement and their original intended purpose. However, it seems to me that a far better approach would be to take the approach used here – i.e. measuring the extent of the land in coastal areas. Since beaches are gently shelving, any sea level rise is greatly amplfied by the slope of the beach.
The measurement I would propose would simply require aerial photographs used for mapping purposes of all the worlds coastlines from today and from 50 years ago. We then simply compare the two to see if any changes are occurring which really matter. Of course this will, at any particular point, include techtonic movement and weather erosion products but so what? What is useful to us is to know the impact of all these factors taken together. We can also get an idea of net sea level rise by adding together the changes to coastal extent across the entire globe.
Even if it were impossible to obtain original photographs then the maps prepared at the time of WWII would allow an analysis of coastal extent accurate to about 50metres. By focussing purely on coastal areas this would certainly permit the actual loss of land area to be calculated to small fractions of a percentage of the total land area.
If the islands are growing with the rising sea levels then they are displacing more water and so contributing to the increase of sea level with respect to the continents. So, in fact, places like Kiribati and Tuvalu should be paying “sea level reparations” to countries like America and Australia. Now that would be irony.
The Daily Telegraph is also carrying the story today. However, despite the scientific results the two scientists are reported, in the last two paragraphs, to have said:
….. islanders still faced serious challenges from climate change, particularly if the pace of sea level rises were to overtake that of the sediment build-up. The fresh groundwater that sustained villagers and their crops could be destroyed.
Prof Kench was also quoted as saying: “The land may be there but will they still be able to support human habitation?”
So after a good piece of scientific research they revert to conjecture.
The trouble with the warmists is while they’re pointing and screaming about the wolf over there, the wolf could already be in the hen house destroying everything.
Imagine spending your career on something that will eventually be proven as a money spinner for rich people and that you’d been hood-winked into pushing their agenda. Should we start building log cabins out in the woods now so they have somewhere to go and hang their heads in shame?
The only problem I have is when Mr Watts, Mr Eschenbach and Mr hill and all the other common sense people are proven right, will they be hoisted into the back of a car and driven down the main streets of New York to a ticker tape parade or simply be ignored and never given the recognition they deserve?
It’s all about controlling the zeitgeist. Facts don’t matter, people can be manipulated, the world “how-it-is” is defined by those who “matter”.
Reality be damned, they’ll re-create reality to further their goals.
Willis Eschenbach says:
June 3, 2010 at 4:29 pm
Actually, I hadn’t thought of that interpretation at all. Instead, despite being a Shamanist and not a Christian of any type, I was riffing off of:
3 Hearken; Behold, there went out a sower to sow:
4 And it came to pass, as he sowed, some fell by the way side, and the fowls of the air came and devoured it up.
I thought you were riffing off the “implausible acts of sexual auto-congress”, hence I leapt straight back to Onan, without stopping to think about any of that new-fangled Jesus literature. Just goes to show, two-thirds of the world don’t know what the other half is thinking.
In today’s Australian newspaper (4/6) by Rowan Callick, Asia Pacific Editor, p 9, Pacific Islands ‘growing not sinking’, with coloured photograhs (in the newspaper, not the link) from the Kench & Webb paper.
http://www.theaustralian.com.au/news/pacific-islands-growing-not-sinking-say-researchers/story-e6frg6xf-1225875237545
And on page 15 an editorial on the same subject.
“Islands defy doomsday scenarios
Coral-based islands have grown in response to rising seas
CLIMATE change advocates anticipating that Pacific islands will be submerged by surging seas have reckoned without nature’s powerful resilience. Research by academics in New Zealand and Fiji published in New Scientist has found that over the past 60 years, all but four of 27 Pacific islands studied have retained their size or grown, some by 20 to 30 per cent.
The researchers do not deny that climate change is having an impact. Sea levels vary, but have been rising by an average 2 millimetres per year in the area studied, far short of the doomsday predictions that islands will be swamped. The researchers detected that coral-based islands have responded by expanding. Climate change is an inexact science. But the findings could ease concerns of Sydney Morning Herald readers who were told last year by medico John Collee that today’s teenagers will see “living coral reefs become curiosities of history”. Nature might dictate otherwise”.
http://www.theaustralian.com.au/news/opinion/islands-defy-doomsday-scenarios/story-e6frg71x-1225875239058
Do coral islands/atolls grow by active coral growth? I thought the island and immediate surroundings were not living coral reefs so couldn’t grow?
costs of adaptation says:
June 4, 2010 at 1:16 am
“It is interesting to go through the National Adaptation Plans of Action (NAPAs), Nationally Appropriate Mitigation Actions (MAMAs) and various other Strategies for Resilience produced by low-lying island states and Bangladesh…”
Why do you ask so many questions when the answer is in front of you?
Don’t you think it should have been called Population Adaptation Plans of Action (PAPAs)…?
Willis:
Again, I have to congratulate you on another great post, anyone who ever took an introductory geology course should have known atolls were unlikely to be inundated any time soon. I don’t know why there ever was any fuss.
I watched the video of your talk at the ICCC, and noticed the similarity of your observations to the cloud patterns you can see on the map linked below. The tropical band of cloud that floats above the ocean moves north and south with the seasons, we are just 3 weeks away from the northern extreme, which is my favorite time of year. I try to stay up until the dawn every midsummer eve.
World Sunlight Map
http://www.die.net/earth/
@Ryan Spear says: June 4, 2010 at 2:45 am
“It is interesting to note that the BBC is claiming that although the islands are becoming bigger, climate change may make them uninhabitable. It is not clear where they sourced this statement or on what basis it was made.”
Obvious! They don’t NEED a source! When things get hotter they expand! That global warming is so bad in the Pacific that these islands will soon be ready to pop!
Vindicated at last – congratulations.
Has anyone named this episode “island-gate” yet? If not, can I propose that as a moniker?
People are a curious lot. They are really impressed when 1 of 500 monkies with typewriters eventually types anything intelligable. Sorry you had to wait so long Willis.
The map shows clearly what you were referring to, and to me it looks very much like a two-dimensional standing wave pattern in those bands, but I cannot think of any physical process that could cause such a pattern to be a static feature for 17 years. The Southern band, in particular, could easily be described as “up, down, up, down, up, down, …” by a centimeter or less, all the way around the planet, giving an overall average that would tend towards zero.
I did note that all of the changes they are dealing with are very small (a few millimeters per year), but these are the outcome of a lot of averaging, detrending, and other numerical steps involving the differences between very large values that fluctuate enormously (by meters and 10’s of meters) from moment to moment and day to day, and are being measured by satellites that don’t have a resolution any better than several centimeters at best.
If I had a gun to my head and had to make a good guess or die, I’d say that it all means nothing, and is simply a spurious artifact of too much data processing, and paying too much attention to tiny bits of residual noise, much like our ‘catastrophic’ temperature trend of 0.007°C per year.
/dr.bill
Regardless of what variations there are in sea levels around the world the fact is that if the seas were rising they would be rising by the same amount world wide. Yes as in the sloshing in a bucket there is sloshing of the sea by gravity, air pressure, currents and so on but there is more water in the bucket if it is being filled.
Our bucket is not filling just because a tide gauge here or there says so, it would require every tide gauge everywhere to say so and I have not seen any paper, anywhere, that has said that.
As an aside I note that all of these studies seem to come from far away exotic places that very few of us ever get to visit. What’s wrong with looking on the coast close to home, or are white sandy beaches, blue sea and sunshine a priori requisites for this kind of research?
Climate bedwetters everywhere must be crying in their milk on this one. Because, while this certainly sounds like good news to any rational person, for them it means they have to move on to some other “proof” of CAGW/CC, like the “death spiral” in the arctic. Oops.
As ever, Willis, excellent work.
The pre-European history of Pacifc Island peoples is filled with sagas of growing island populations being forced to send off their excess people in tiny and primitive craft to become explorers and settlers around that great ocean. The New Zealand Maori regard themselves as tangata whenua, people of their current land, but treasure their oral histories of the various waka, canoes that made the voyage from the crowded islands of the Hawaiian Archipeligo generations ago carrying the founding members of the various tribes of modern Aotearoa-New Zealand.
So why don’t the Tuvaluans follow the same proud tradition? Or is it easier for them to join the ridiculous culture of blame, in which someone else must pay for their overpopulation of tiny atols. I find it strange that Western ecologists are usually very ready to blame overpopulation for anything they stumble across, but when cases of very obvious overpopulation, which is the basis of Tuvalu’s problems, it’s much more fashionable to wheel out all the ridiculous AGW canards instead of stating the blatantly obvious.
OT, I know, but while I’m on the subject of canards, I find it sickening that Obama is whipping up anti-British sentiment in the USA by his constant use of the title ‘British Petroleum’ for an oil company which is very largely an American conglomerate, in which BP is only a set of initials and has not stood for British Petroleum for a decade. Very nasty use of the xenophobia card. Still, for a man who is so poorly educated that he believes he exhales a dangerous and piosonous greenhouse gas, quite unsurprising.
Paul Clark: June 4, 2010 at 2:57 am
Paul, I visited your website Planetary Vision and read your analysis of the Keeling Curve and the effects of the precise siting of the Mauna Loa station. I’ll read it all again in detail, but that’s quite a remarkable job you’ve done.
/dr.bill
I believe it was here at WUWT, in the last year, that I learned that some Pacific Islands are subsiding in relationship to sea level because of aquifer depletion. Add that to the expected response of living coral and continued sedimentation, and the study in this thread, and the Alarmists really do not have much left to whine about.
Pytlozvejk says:
June 4, 2010 at 3:28 am
Oh, very good, sire, I confess myself bested.
Puts me in mind of the sign I saw at the Snoopy Ice Arena in Santa Rosa, California:
“For safety reasons, please do not skate faster than the average speed of the other skaters”.