Guest post by Andi Cockroft
I certainly am standing on the shoulders of Giants here, citing our very own Willis Eschenbach’s excellent essay on Pacific Island Nations and their “shrinking” coral reefs. Published in these hallowed pages just over two years ago as “Floating Islands”.
As background, I would thoroughly recommend a re-read – however I will borrow bits and pieces from Willis’ work – heck, you may as well assume that (towards the end) I have plagiarised much from Willis’ excellent post.
But now for today’s story.
Sitting eating breakfast under the golden arches, a very rare event for me, I was drawn to something in the local newspaper here, the Dominion Post – and as I’ve seen in comments in other posts of mine, the owners of the Dom, Fairfax Media, are so unmitigatedly biased it’s unbelievable. I say this is a rare event for I rarely eat under the arches, and never ever read the rubbish in the Dom – but hey there’s an exception to every rule.
As reported in print at the Dom, online at the Beeb here and the Telegraph here; the Kiribati Government (pronounced kirr-i-bas or kir-ee-bahs – the local affectation of “Gilberts” from Colonial days) is looking to purchase around 23 Sq km (9 Sq ml) on nearby Fiji’s Vanua Levu as a staging post for relocation of the Kiribati’s 100,000 people.
Autonomous Mind picks up with a repost here – more later
According to the Kiribati Government Website here, Kiribati is composed of 32 atolls and one raised coral island, dispersed over 3,500,000 square kilometres, (1,351,000 square miles) straddling the equator, and bordering the International Date Line to the east. Total land area is 811 Sq km; this includes three island groups – Gilbert Islands, Line Islands, Phoenix Islands. 21 of the 33 islands are inhabited. The population is [was] 112,850 (July 2009 est.).
So whilst we have here what looks to me to be a resurrection of the “Give us more cash” doctrine, I can’t actually blame them – no more than I can blame the beggar who can make more money from his trade than getting a real job (I once knew a guy who earned twice what I did just by begging part-time on London’s Oxford Street – but that’s another story)
If just by creating these stories, the West gives them heaps of dosh – why would they not come back for more – stands to reason.
But is this a valid call or not – well I suppose it depends on your point of view.
Way back in September 2011, Kiribati’s President Anote Tong and the UN Secretary General Ban Ki-moon issued a joint statement [emphasis mine]:-
“[they]….. today stressed that climate change posed the most serious threat to the livelihoods, security and survival of the island nation’s residents and the inhabitants of the wider Pacific region, saying the phenomenon was undermining efforts to achieve sustainable development.
Both leaders reaffirmed the need for urgent international action to reduce emissions of the harmful greenhouse gases and underlined the need [to] make climate change adaptation funding available to finance the implementation of critical programmes to tackle the impact of climate change on communities there….”
Full text here.
Yep, sounds just like “give us the cash” to me – but again is there a clear and present danger?
If you have read Willis’ essay by now, you probably already know the answer, but I’ll just quote a bit of what others have to say:
Just as Mannian climatology would use proxies, so I regret I will have to do – there just is insufficient data (or I am too inept to find/mine it), that reference has to be made to nearby Island Nations who do have readily accessible tide-gauges (if you can help me out here please do so in comments below)
http://www.john-daly.com/ has this neat figure:
The graph below was so faint, I’ve had to Photoshop it – but this originally for the Maldives from British Oceanic Data Centre (BODC) here:-
Apart from the obvious disconnect in the early 90’s, which may be a location problem, certainly from 1995 to 2004 shows no real trend using my eye-ometer.
And don’t take my word for it, a paper in New Scientist by Paul Kench and Arthur Webb entitled Shape-shifting islands defy sea-level rise (behind paywall here) actually found that far from being inundated, the majority of coral islands are actually growing not shrinking – they can adapt to sea-level
Reported by Australia’s ABC here
Climate scientists have expressed surprise at findings that many low-lying Pacific islands are growing, not sinking.
Islands in Tuvalu, Kiribati and the Federated States of Micronesia are among those which have grown, largely due to coral debris, land reclamation and sediment.
The findings, published in the magazine New Scientist, were gathered by comparing changes to 27 Pacific islands over the last 20 to 60 years using historical aerial photos and satellite images.
Auckland University’s Associate Professor Paul Kench, a member of the team of scientists, says the results challenge the view that Pacific islands are sinking due to rising sea levels associated with climate change.
“Eighty per cent of the islands we’ve looked at have either remained about the same or, in fact, gotten larger,” he said.
“Some of those islands have gotten dramatically larger, by 20 or 30 per cent.
“We’ve now got evidence the physical foundations of these islands will still be there in 100 years.”
But, the article continues [bold mine]:-
Dr Kench says the growth of the islands can keep pace with rising sea levels.
“The reason for this is these islands are so low lying that in extreme events waves crash straight over the top of them,” he said.
“In doing that they transport sediment from the beach or adjacent reef platform and they throw it onto the top of the island.”
But Dr Kench says this does not mean climate change does not pose dangers.
“The land may still be there but will they still be able to support human habitation?” he asked.
Adelaide University climate scientist Professor Barry Brook says he is surprised by the findings.
So just why are the Kiribatians looking to relocate? Is it a real problem? Is it just “give us the cash”, or is it some other problem?
Many of these smaller Island Nations are doing a fantastic trade in tourism, indeed the Maldives is building airstrips right, left and centre. Kiribati has two international airports (Godzone only has three or perhaps four).
As Willis points out, water appears to be a big issue, as is coral mining and fishing (yes fish can upset the coral atoll growth). Others point to rubbish – simply put they are running out of places to dig holes and bury the stuff.
But I do want to bring Willis’ essay in here regarding the dynamics of fresh ground water in the coral environment – this bit I really like:-
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 [Willis] drew up.
Note that the sea water 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 fresh water pushes down the surface of the sea water underneath it, forming the bottom of the “lens” shape. The lens is wider 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 is floating on a sea water table in a porous coral rubble and sand substructure. If there is no rain, the fresh water 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 sea water.
So the claim, that a sea level rise can cause the sea water to intrude into the fresh water lens, is not true either. The fresh water lens floats on the sea water below. A rise in the sea level merely moves the lens upwards. It does not cause salt water to intrude into the lens.
I find Willis’ explanation of why such islands will not be inundated by sea-level variations equally fascination – this time Willis relies upon none-other than one Charles Darwin:-
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, 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 metres tall, hey have survived a sea level rise of up to three hundred plus feet (call it a hundred metres) within the last twenty thousand years. Historically they have floated up higher than the peaks of drowned mountains.
So the [this] claim is not true either. Atolls are created by sea level rise, not destroyed by sea level rise.
More on Darwin’s Atoll theory from our friends at Wikipedia here
And, as Willis sums up, there are significant stress factors affecting relative sea-level and fresh water salinity.
- A limited supply of fresh water – no rain (or rain runs off to sea) – wells run dry or saline
- Wind erosion is ongoing, and as long as deposition keeps pace then no issues.
- Coral-grazing fish provide coral sand for storms to deposit – kill the fish and lose the supply of sand
- Coral health is vital for production of coral sand – mine the coral or sell specimens and kill the supply of sand
- Use of coral and coral sand for building will serve to exhaust the supply.
And one final quote from Willis:-
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, digesting the food, and excreting the ground coral.
Does it make sense then for Kiribati to buy (via grant no doubt) 23 Sq Km of Fiji – especially given Fiji’s tumultuous political regime – and would it have a hope of supporting 100,000+ people there? Indeed, would the Kiribati Government have a hope in hell of getting its population to sell-up and move to a foreign environment and culture?
With tourism to such places as Kiribati in such high demand, just who is going to stay behind to service the trade? Perhaps a few hardy souls, or will Kiribati simply sell off its islands to the super-rich to enable it to buy its way into other Nations?
From a quote in Autonomous Mind here by Dr Nils-Axel Mörner, former president of the International Association of Quaternary Research’s Commission on Sea Level Changes and Coastal Evolution. [emphasis mine]
With respect to the article on March 7 by Paul Chapman [Telegraph, Wellington, NZ] on the future of Kiribati, I have to protest and urge all readers to consult the only “hard facts” there are, viz. the tide gauge record of the changes in sea level.
The graph reveals that there, in fact, is no ongoing sea level rise that threatens the habitation of the islands. This is the hard observational fact, which we should all face before starting to talk about future flooding and the need for evacuation.
If the president of Kiribati, Anote Tong, claims that the islands will soon be flooded and that there is an urgent need to buy new land for possible future refugees, it is the president’s own tactical idea in order to raise money from abroad. Let us respect the observational facts and stay away from invented disasters.
No matter which way you look at it, the small (if any) sea level variations we are experiencing would have no notable effect. There are other far more serious anthropogenic factors at work here – but CAGW and/or Sea-Level are not included.
PS Again, I would really urge reading Willis’ original article.