Kilwa Kisiwani Gereza

Guest Post by Willis Eschenbach

I love African names. I mean, could there be a more euphonious name than “Dikembe Mutumbo”? That’s just poetry. In any case, this post is about a place charmingly yclept “Kilwa Kisiwani Gereza”. It seems it’s a new poster child for the dire effects of “climate change”. This alleged victim of evil sea level rise is the ancient African trading center of Kilwa Kisiwani in Tanzania, located at 8.97°S, 39.50°E. The city was originally of Muslim origin. It was taken over briefly by the Portuguese explorer Vasco de Gama in 1502. There’s a World Heritage Historical Site there, crumbling into ruin. The Heritage folks say:

The ancient fortress of Gereza … is slowly collapsing into the Indian Ocean as sea level rises due to climate change.

Figure 1. The city of Kilwa Kisiwani (“Kilwa on the Island), from a Portuguese drawing done some time prior to 1572. Source.

So what is all of the sea level hyperventilation about? For that, we need to turn to the Global Heritage Network. Here’s what they have to say:

Figure 2. Information on the fortress of Gereza from the Global Heritage Network. Date of the lower photograph unknown. Photos from the GHN Briefing Paper (PDF)

Not a pretty picture …

The city has an interesting history. A Portuguese site says:

Currently only the turret of Gereza is of Portuguese origin, with the remaining structure undergoing significant changes after the Portuguese left the island in 1512, giving place to the Omani sultans, which have shared power for centuries. The main wooden gate, decorated with floral motifs mixed with verses from the Koran, is the original and clearly of Arab origin. A sign in front, already a good few decades old, cites an urgent conservation project implemented by the department of antiquities of Tanzania and UNESCO, with Norwegian funding. The state of the structure is pitiful, which well explains the fact that since 2004, this place has been on the prestigious list of World Heritage Sites in Danger. The disassembled, out-of-order spotlights in front of the fort testify to that very well.

Kilwa was an important city in the Muslim commercial empire, which extended from the East African coast to the Moluccas, passing through the Persian Gulf and India, though at the time the Portuguese arrived they were already in decline. In 1502, Vasco da Gama took over the city, making the king a vassal of of the Portuguese King. With the proceeds of the first tribute in gold from the new African possession the famous monarch ordered the making of the famous “Custodia of Bethlehem”, one of the masterpieces of Portuguese art. Simultaneously with Sofala, a fortress in Kilwa was erected in 1506, under the direct supervision of D. Francisco de Almeida, the first structure built of stone and mortar in the region – a typical medieval castle with four corner towers and one tower, not in the central square, but leaning against the main face of the wall. Its main function was to provide shelter to passengers of the boats on the India route. The Portuguese presence, however, was quite short. Due to high maintenance costs and questions of military strategy (there were already forts near the Mombasa and Mozambique), Kilwa was abandoned by the Portuguese in 1512, again assuming the status of one of the city-states of the Swahili world. It would then be occupied and reoccupied by successive sultans that would adapt it to their needs and desires. In 1843, the transformation of nearby Kivinje in seaport led to the abandonment of Kilwa, and the consequent destruction of their buildings.

There’s a detailed history of Kilwa Kisiwani here .

So is “climate change” in the form of sea level rise really a problem for the Heritage site, the fortress Gereza? The Global Heritage Network folks say it is. But there is no mention of that on their main information site.

Well, let’s do what the Global Heritage folks didn’t do … take a look at the observations to see what the sea level is doing in that area. The nearest (and only nearby) tide station with a somewhat long-term record is in Zanzibar, and is available from the web site of the Permanent Service for the Mean Sea Level (PSMSL). You can also download satellite data showing sea level changes for the area just offshore of Kilwa Kisiwani (9°S, 40°E) from the University of Colorado. I have overlaid them below.

Figure 3. Tide gauge (Zanzibar) and satellite (offshore from Kilwa Kisiwani) records of sea level height. Photo of the World Heritage Site (photo source).

As you can see, we have very good agreement between the satellite and tide gauge records, which increases the confidence in both. As you can also see, over the last quarter century the massive recent sea level rise has brought the local sea level about back to where it was 25 years before …

So we can throw out all of the nonsense about sea level rise. Since 1985, sea level dropped about two-four inches (50-100 mm) and rose back up again. Anyone who thinks that was the threat to the ancient fort isn’t following the story.

So if sea level rise is not the cause of the fort crumbling into the sea, what is? From an examination of the site, it seems obvious that the answer is plain old garden variety erosion. Here’s what the area looks like:

Figure 4. Overview of Kilwa Kisiwani.

This is a tidal laguna with surrounding marshlands. There are large areas of mangroves, and extensive sedimentation. Given the area of the laguna and the size of the outlets, with the local ~ four foot tides it gets fairly strong tidal currents. In other words, as a seaman I can assure you that we have no reason to expect that any of the islands, sandbars, and channels will have great permanence. In Figure 5 there is a closer look, this time an aerial view looking southeast along the coast to duplicate Figure 1, reveals more about the underwater geography.

Figure 5. Kilwa Kisiwani Island. Note the underwater shoal where the island has been eroded, offshore from the historical remains of the ancient fort at the lower right. 

This type of sedimentary, marshy land is never stable. Year after year the islands and the channels shift and change. Rather than being surprised that the 500-year-old fort is falling in the ocean, we should be surprised that it has lasted this long.

This kind of sedimentation and buildup is very sensitive to the immediate conditions. Consider the sand and sediment in the lower picture in Figure 2. You may not have noticed that the sand has built up on the left side of the ancient fortress. Contrast that to the way the sand has eaten away, leaving only stone, on the right side of the fortress. The cause of this is the mere presence of the stones in the foreground. You can see how they have changed the circulation, and are causing even further erosion at the base of the fort … and the Global Heritage folks want us to believe the culprit is the (non-existent) sea level rise?

This is another example of why I say that the problem in climate science is not communication. The problem is not that the scientists have not figured out how to get their message across.

The problem is bogus science and, as in this case and far too often, exaggerated or false claims. Once again, a serious climate claim from an internationally respected organization (this time the Global Heritage Network) has been shown to be a complete fantasy … and there’s no amount of better spin or framing or communication that will solve that.

w.

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73 thoughts on “Kilwa Kisiwani Gereza

  1. Fantasy? maybe you are being too kind here, I think it is another example of the huge FRAUD which is being spun worldwide.

  2. Wrong units in:
    “So we can throw out all of the nonsense about sea level rise. Since 1985, sea level dropped about two-four inches (50-100 cm)”
    [Fixed, thanx. ~dbs]

  3. The chief problem is that many of these so called ‘scientists’ have been so brainwashed that the only explanation of ANYTHING is global warming.
    They have lost the ability to think rationally, and to look at other possibilities.
    Global Warming, CO2, and/or Sea Level Rise have become the “go-to” explanation for nearly every problem that occurs, anywhere.
    Forbid, that they actually SHOW that any of this is actually happening in the area concerned before actually laying the blame , let alone that it is the cause.
    In other cases, even a very vague correlation is now proof enough, for cause.
    What has happened to the science of PROOF ???????????

  4. So sea levels change. So what. The sediment record shows sea levels have changed throughout geological history. We will never alter this natural change.
    During the Cretaceous central USA was a vast inland sea. This was the cause of the formation of the Book Cliffs in Utah and Colorado together with the vast clean coal reserves in those two states.

  5. The problem is that this local “problem” needed to pull the heart strings of a more global audience. Just saying: “erosion is destroying this …” isn’t going to bring in the funding. But saying: “your lifestyle is having a direct effect on this thing, and if you want to salve your conscience for your life of luxury, you known what you have to do”.
    What they don’t realise is that most people see any mention of “global warming” as an immediate indicator of a scam. Or to put it in a way they will understand it’s a bit like saying: “Genuine heritage (as purchased on Ebay)”.

  6. Willis, you may want to correct your metric values! 2-4 inches is 50-100 mm (5-10 cm), not 50-100 cm.
    L.
    [Fixed, thanks. ~dbs, mod.]

  7. Great article. You have one glitch:
    “two-four inches (50-100 cm) ” should read 50-100 mm.
    Keep on the good work – it gives me a lot of ammo in my arguments with the alarmists.
    Slowly we will win the battle.

  8. Kilwa Kisiwani in Tanzania, located at 8.97°S, 39.50°N.
    Willis, from your first paragraph…..Need to change 39.50 to E longitude not North.
    Another great find. Keep up the good work.

  9. Well done, another lie exposed. It stagers me that these people can keep on coming out with this kind of utter garbage. Have they no shame?

  10. Willis Eschenbach says: “As you can see, we have very good agreement between the satellite and tide gauge records, which increases the confidence in both. ”
    Well since the satellite data is “calibrated” off the tidal gauges with a short term variable correction made to satellite data it’s not too surprising they agree. I would not put too much weight on that argument.
    Good post though, wins you a place in the Global (Climate) Heresy Network.

  11. ” The disassembled, out-of-order spotlights in front of the fort testify to that very well.”
    Sea level rise has disassembled my spotlights too!

  12. The standout sentence in your article:
    “Let’s do what the Global Heritage folks didn’t do.”
    I am not getting immune to these revelations. It still shocks me every time I see that people in high places are down-right lying.
    Thank you once again, Willis, for the very important work you are doing to at least keep the truth in the race.

  13. Kilwa is semitic (Arabic) for kidney. I had a look at the shape of the island and it does have the shape of a kidney. Just thinking. And it will retain that shape for a very long time………………………..

  14. Unlike the warmists, you can’t have it both ways, Willis:
    …located at 8.97°S, 39.50°N.

  15. Is it possible that the Global Heritage Network would be in line for even more ‘aid money’ from the UN if they can claim (perhaps they don’t have to prove) sea level rise because of AGW?
    Seems to me that this fort is a money pit and an awful lot of ‘heritage aid’ has already been ‘lost’ on it. Something you would no doubt call a ‘boon-doggle’, Willis.

  16. Well posted, Willis. Is it me, or is there an actual declining trend in sea-level using that data & the dates shown?
    This is so typical of the lousey reporting & distortion & down right lies that masquarade as science these days. Never let the facts get in the way of a good story!

  17. Is the rising “…in the pipeline”?
    And does this depend on what is in the pipe you’re smoking?

  18. Climate change, aka manmade climate change, has become the modern-day equivalent of “God” or “the gods” in explaining the forces of nature. Now, as in olden times, it is because of something we did (burned too many fossil fuels) or didn’t do (switch to non-“carbon-emitting” or “green” energy), thus making the god or gods of climate change angry. When the whole CAGW/CC/etc. fraud and greed-driven hysteria has finally been laid to rest, figuring out how and why it all happened will take decades. It will be a puzzle for future sociologists and psychologists. Never again will the word of scientists, and especially scientific organizations be taken as the truth. Perhaps that is a good thing.

  19. So, essentially, they’re ever so worried the pesky castle will disappear because they’ve spent so much time, money, and resources on restoring it and protecting it from (weird) erosion, (acid) rain, (unnatural, most likely, manmade) storms, natural (national) climate, natural (regional) weather, and of course the degradation of crappy building materials as time moves on.
    Oh, right, they didn’t, so, essentially, they just want more funding without actually having to spend it on conservation.

  20. Another great post Willis !!
    “Rather than being surprised that the 500-year-old fort is falling in the ocean, we should be surprised that it has lasted this long.”

  21. Thanks Willis.
    This is another example of why I say that the problem in climate science is not communication. The problem is not that the scientists have not figured out how to get their message across.
    The problem is bogus science and, as in this case and far too often, exaggerated or false claims.

    I spent a recent evening at a dinner party next to a ‘social engineer’ who is devoting his life to improving the communication of “climate change” (he would not utter ‘global warming’), and how to mitigate it, on small islands in the south Pacific. Unable to come to some point of cogent conversation wrt climate, I turned to paleo-anthropology. I was fascinated how the science around climate isn’t even questioned, or viewed with any scepticism. It is indeed all about how to package this three-day old fish to conceal the odor.

  22. And gee, Kilwa Kisiwani Gereza’s location on the rifted portion of the African Tectonic Plate would mean that it’s underpinnings would never EVER be prone to vertical tectonic movements! /sarc

  23. Willis shines the bright light of good science, research and good sense on another bogus problem.
    I am waiting for your book, Willis!

  24. There’s an Error in 2nd para after the sea level gauge chart “about two-four inches (50-100 cm)” Should be mm not cm. Otherwise great work Willis.
    [Thanx, fixed. ~dbs, mod.]

  25. Of course, the real problem is that, if you were the conservationist in charge of this fort, and you had just been told that there was no money in the standard architecture budget due to cuts, but there was a lot of money available if you put a grant request in to the UN Climate Change fund, what would you do?
    In fact, there’s a good chance that the standard architecture budget has been cut because they have been forced to buy a windmill and solar panels for the conservationist’s head office. So if you put in a claim to save your fort from ‘Global Warming’, you’d just be getting some of your original money back…

  26. “Rather than being surprised that the 500-year-old fort is falling in the ocean, we should be surprised that it has lasted this long.”
    A testament to 500-year-old construction techniques. 😉

  27. Depending on the type of construction, mortar mixed with sea water tends to “melt” over time.

  28. Further reading would seem to indicate that the erosion has more to do with the cutting down of the local mangrove forests that anything else. But hey, why blame the locals when you can blame nasty westerners and their evil ways? Guilt is also a big money spinner.

  29. Give it up, Willis. All these facts just make folks’ heads hurt. As everyone KNOWS, we’re all going to drown if we don’t burn up and die first. You probably don’t even believe in “The Goracle”.

  30. I love African names. I mean, could there be a more euphonious name than “Dikembe Mutumbo”? That’s just poetry.

    Dikembe Mutombo
    From Wikipedia, the free encyclopedia
    (Redirected from Dikembe Mutumbo)
    Dikembe Mutombo Mpolondo Mukamba Jean-Jacques Wamutombo[1] (born June 25, 1966), commonly referred to as Dikembe Mutombo, is a retired Congolese American professional basketball player, who last played for the Houston Rockets of the NBA. He was the oldest player in the NBA at the time of his most recent season.[2]

    The euphonious-ness is greatly enhanced by the selective shortening of his full name, of which the attempted pronunciation could conceivably be used as a roadside sobriety test.
    Who knew Willis paid so much attention to basketball?

  31. The moment I saw the overhead image, it was obvious this was a case of plain jane erosion.
    Rivers move. Curvy rivers become curvier, create islands, then destroy them. The faster the water flow, the faster the erosion.
    If anything, higher sea levels in the region would slow the flow of water, which would increase sedimentation, slow erosion and help preserve the fort.

  32. Thirty or forty years ago my now deceased mother-in-law worked for National Geographic as a picture editor. She loved her job. She had a cadre of fussy old academics that questioned the historical accuracy of the minutest detail in every picture they published. If the slightest hair was misplaced she was soon overwhelmed with letters of complaint, sometimes even direct telephone calls a day or two after publication. That attention to accuracy seems to have now been lost by both the published media and academia. It now seems to be totally acceptable to bend the rules if that is what is necessary to obtain/retain your funding, or to maybe just ‘make your point’.
    My guess is that when you mix together the right brained ‘true believers’ that now seem to have infiltrated both the media and at least certain area of academia with the quest for ever increasing profits by the published media and ever increasing budgets in academia you wind up completely bastardizing both systems.

  33. Willis
    Thanks. Always like your gems.
    In case you missed this:
    http://www.lethbridgeherald.com/national-news/study-finds-canada-s-arctic-coastline-eroding-faster-than-anywhere-else.html
    Good example of spin doctoring, eh? Headline says:
    Study finds Canada’s Arctic coastline eroding faster than anywhere else ANYWHERE ELSE ?? Got that? Oops. It goes on to say, “…in the circumpolar world.” Anything for a headline.
    Then they slip in a sneaky sentence that states:
    While they can’t yet prove it, scientists suspect that gradual washing-away along thousands of kilometres of gravelly northern shoreline is speeding up.
    So in reality it is non article, but it makes the front page. Should I be surprised? My local rag is called the Lethbridge Herald. I’ve renamed it, The Left Bridge Herald.
    Regards
    Clive

  34. Kadaka, the word you were looking for is not euphonious-ness, but euphony.
    Hate to be picky, but when I was a kid my dad insisted that I had at least one of his dictionaries to hand to aid both reading and writing. Early training is inescapable.

  35. “The problem is bogus science and, as in this case and far too often, exaggerated or false claims. Once again, a serious climate claim from an internationally respected organization (this time the Global Heritage Network) has been shown to be a complete fantasy … and there’s no amount of better spin or framing or communication that will solve that.”
    Accurate and to the point!
    A child’s song summarizes it:
    “The foolish man built his house upon the sand…. and the walls came atumblin’ down!”

  36. Looks like the “deliberate errors” gave much satisfaction to the discoverers. 🙂
    I enjoyed my 20 years in SA and to show I’m not bothered by future sea level
    rises I named my house “Inanda”.

  37. By accepting the AGW bull, the heritage conservationists have convinced themselves that there is nothing they can do to protect this historic site. If instead, they treated it as any other area experiencing coastal erosion, they could employ any of a multitude of techniques many of which can be quite cheap.

  38. Regarding Dikembe Mutombo, he studied at and played for Georgetown U, and gave the commencement address there last May. He is a class act, having devoted his energies and fortune to healthcare foundation serving his native Congo. He sounds like a 100-ton excavator in a gravel pit, which along with his great height makes him very imposing.

  39. I guess the old advice from Matthew still applies,
    Matthew 7:24-27 (New International Version, ©2011)
    The Wise and Foolish Builders
    24 “Therefore everyone who hears these words of mine and puts them into practice is like a wise man who built his house on the rock. 25 The rain came down, the streams rose, and the winds blew and beat against that house; yet it did not fall, because it had its foundation on the rock. 26 But everyone who hears these words of mine and does not put them into practice is like a foolish man who built his house on sand. 27 The rain came down, the streams rose, and the winds blew and beat against that house, and it fell with a great crash.”

    Difference in the old painting and new satellite image, shows the shifting sandbars.

  40. DD Moore, you read my mind with the Matthew reference! I was about to go on the snark-attack and say something along the lines of “Maybe if they’d put Scripture on the front door instead of the Koran…”

  41. PaulH says:
    “Rather than being surprised that the 500-year-old fort is falling in the ocean, we should be surprised that it has lasted this long.”
    A testament to 500-year-old construction techniques. 😉

    I would guess that Stonehenge and the pyramids will remain standing long after our modern cities have crumbled.

  42. And so long as we’re here, might I ask why every structure +100 years old must have some sort of Historical / Preservation / Restoration Society attached to it? Certain structures of cultural significance, I can certainly understand. This castle, however…I’m not seeing it. Based on the post, it seems like even the Portuguese who originally built it had second thoughts within the first decade.
    Maybe it’s an American mindset, but sometimes it’s just an old building. Let Earth reclaim the materials. I shudder to think that someday, 150 years from now, there will be some sort of WUWT Poster Historical Society wasting money to keep my current house safe from the tolls of Anthropogenic Termite Hunger.

  43. Great article, Willis. You know more about beaches and such than all the Warmista combined. As for the Heritage folks, I know a little about them and it seems to me that their staff is tiny. I think they are just passing on the buzz that is popular among academics.

  44. Willis,
    Talking of poetry have you heard the tale of the ‘Omumbo – rombonga’ tree which grew bananas, dates, coconuts, melons, millet, yams, cassava, maize, pineapples and oranges?
    Almost as good as ‘Dikembe Mutumbo’ methinks

  45. TonyG says:
    April 21, 2011 at 1:15 pm
    “I would guess that Stonehenge and the pyramids will remain standing long after our modern cities have crumbled.”
    And German Hochbunkers. With a Braunschweiger Bewehrung for the roof. (5m thick concrete-steel mesh)

  46. reason says:
    April 21, 2011 at 2:14 pm

    And so long as we’re here, might I ask why every structure +100 years old must have some sort of Historical / Preservation / Restoration Society attached to it? Certain structures of cultural significance, I can certainly understand. This castle, however…I’m not seeing it. Based on the post, it seems like even the Portuguese who originally built it had second thoughts within the first decade.
    Maybe it’s an American mindset, but sometimes it’s just an old building. Let Earth reclaim the materials. I shudder to think that someday, 150 years from now, there will be some sort of WUWT Poster Historical Society wasting money to keep my current house safe from the tolls of Anthropogenic Termite Hunger.

    I can see the historical designation but only because of the archaeological significance of the site. With parts of it 500 years old and a host of different occupiers, seems like there’s stuff to be found out by careful excavation of parts of the area. The garbage dump would be particularly interesting.
    Also, the fact that part of it is in the water may not mean everything is lost. I’d go down with scuba and see what’s down there …
    When I was working in Morocco I remember seeing an old building crumbling on a hill. I asked about it and was told it was a Roman fort … dang, I thought, a couple thousand years old. So you are right, sometimes an old building is just really, really old. It did remind me that I wasn’t the first guy from another continent working in Africa …
    w.

  47. Great information, Willis. Thanks! I particularly appreciate you pointing us to the sea level links — those are useful sites that I will keep bookmarked.

  48. Looking at the fortress in the photo that you have provided, I also have to wonder how much of the damage is due to the other great threat to ancient monuments, that of locals mining for building materials. Hadrian’s wall in the north of England is a wonderful example; in most unreconstructed ares, it is only 3 feet high, and many of the stones (some with inscriptions) can now be found in local farmhouses, barns and in other local structures.

  49. Utterly beautiful images. They evoke a strongly seductive sense of nostalgia in me. Old engravings were described by those who made them back in the mid to late 1800s as such that each line carved in the copper printing plate being its own universe, as containing everything the person making that line was capable of, in the minute it was etched. That was back in the day before science, noble science, was corrupted by charlatanism, back when children’s books were about flying fishes and ancient islands rather than a falling sky minus the knowledgeable tale of Chicken Little.
    Old Island: http://oi51.tinypic.com/n1qcsk.jpg
    Flying Fishes: http://oi54.tinypic.com/314uy6c.jpg

  50. Thank you Willis,
    This was a most interesting post, yet again.
    The links in your story were very worthwhile reading.
    As was the Dikembe Mutombo Foundation (which inc partners Annan and Gore) and a resultant 150 bed hospital and research centre. http://www.dmf.org/
    The Aluka link states James Kirkman (1955) apparently excavated a seaside wall on the structure [?Gereza fort].
    The archaeology of Islam in sub-Saharan Africa (1999) Timothy Insoll provides some detail on the use of coral as a building material (p173-google).
    Perhaps the ransacking of the city by the Portuguese in 1505 when they sailed in with 14 Man O’Wars [probably carracks] and 6 caravels provided reuse of [coral] material for the building of the Gereza fort (video on Heritage site viz Basil Davidson referring to the account of Hans Meyer (?sp) Kilwa and its Destruction).
    Anyway, as you state the garbage dump would be very interesting, as would a dive.
    ‘……The problem is bogus science and, as in this case and far too often, exaggerated or false claims.’
    True, but here are some sun, sails and fish of the area. http://www.kilwaruinslodge.com/

    Would you or another WUWT poster please explain the phenomena of Lake Kivu, Nyos and Manoun. Or are the wiki articles reasonable?

  51. Joe Crawford says:
    April 21, 2011 at 8:41 am
    It now seems to be totally acceptable to bend the rules if that is what is necessary to obtain/retain your funding, or to maybe just ‘make your point’.

    That would be “Post Normal Science” for 400, Alex.

  52. Jessie says:
    April 22, 2011 at 3:01 am

    Thank you Willis,
    This was a most interesting post, yet again.
    The links in your story were very worthwhile reading.
    As was the Dikembe Mutombo Foundation (which inc partners Annan and Gore) and a resultant 150 bed hospital and research centre. http://www.dmf.org/

    Near as I can tell he’s one of the good guys.

    The Aluka link states James Kirkman (1955) apparently excavated a seaside wall on the structure [?Gereza fort].

    Yeah, I’m not a member of Aluka so I couldn’t investigate further. I was wondering what is known of the erosion of the underpinnings of the fort. Was it sudden, or did it happen over centuries … and was Kirkman involved? “Excavation” of a “seaside wall” doesn’t sound like the best of long-term plans to me …

    The archaeology of Islam in sub-Saharan Africa (1999) Timothy Insoll provides some detail on the use of coral as a building material (p173-google).

    Having built with it, I can say it’s lousy construction rock and makes even worse construction sand (for concrete) …

    Perhaps the ransacking of the city by the Portuguese in 1505 when they sailed in with 14 Man O’Wars [probably carracks] and 6 caravels provided reuse of [coral] material for the building of the Gereza fort (video on Heritage site viz Basil Davidson referring to the account of Hans Meyer (?sp) Kilwa and its Destruction).

    I missed that discussion, you have a link?

    Anyway, as you state the garbage dump would be very interesting, as would a dive.
    ‘… Would you or another WUWT poster please explain the phenomena of Lake Kivu, Nyos and Manoun. Or are the wiki articles reasonable?

    Wiki articles agree with what I know. Volcanoes outgas a variety of gasses. In these lakes it seems the pressure of the water “caps” the gas until it suddenly overturns and the gas bubbles out in quantity.
    w.

  53. Willis,
    ‘I missed that discussion, you have a link?’
    Yes, your link: http://ghn.globalheritagefund.org/explore.php?id=1084
    go to LHS and first video narrated by Basil Davidson
    8.35 mins about 3.55 mins into video narrates de Gama’ initial voyage to the area in 1498 (de Gama was 6yrs old) and 7 years later viz larger Portuguese (?) fleet ‘a German eye witness by the name of Hans Meyer(?sp) has left an account of what took place’
    I had thought most archives were lost in the Lisbon earthquake of 1755.
    General interest 🙂
    The only Hans Meyer I found in relation to this area of Africa was the German geographer. ‘In 1911 funded from his own assets a Chair in Colonial Geography University of Berlin.’
    also see: Dunbar GS (2001) Geography: Discipline, Profession and Subject since 1870: An International Survey p24-30 (google books)
    Ascent to the Summit of Kilima-Njaro
    Hans Meyer Proceedings of the Royal Geographical Society and Monthly Record of Geography,New Monthly Series, Vol. 12, No. 6 (Jun., 1890), pp. 331-345
    Hans Meyer Les Barundi: Une etude ethnologique en Afrique orientale 1984 (trans) 276p
    http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=3248160
    also google Mountain Research and Development 2004 V24(4)
    Thank you re response to the lakes question.

  54. Apologies
    de Gama would have been 38 0r 29 yrs of age on first voyage to Kilwa.
    However it appears that Admiral d’Almeida captained the second voyage (1505)resulting in Portuguese succession until the Omanis finally expelled them from Gulf, Pemba, Zanzibar and Mombasa. (1650-1696)

  55. Willis,
    Yeah, I’m not a member of Aluka so I couldn’t investigate further. I was wondering what is known of the erosion of the underpinnings of the fort. Was it sudden, or did it happen over centuries … and was Kirkman involved? “Excavation” of a “seaside wall” doesn’t sound like the best of long-term plans to me …
    Yes I agree. Unless one was interested in maximum gain (artefacts) for minimal outlay.
    Norman King (1917) and GSP Freeman-Grenville & Neville Chittrick have some reasonable publications (1960s-) on the history, building material and architecture of the area, inc to the north of Mafia Island (Kilwa Marine reserve).
    Also this site (Archnet) http://archnet.org/search/results.jsp?search_id=1449479&scope=system&module_title=Digital+Library%3A+Site+Names
    What do do imagine the structure along the island coastline a km or 2 directly east from ‘the ‘fort’ of Kilwa Kisiwana Island to be? A jetty?
    All in all, an odd place to be mapped and shown for a ‘fort’. The island is on a tidal river and the fort inland to the ocean?
    I would think a slave trading depot. Not as Basil Davidson purports of the Portuguese trade in humans. I imagine for the Muslim (or Swahili) slave trade + collection point for the inland mineral trade/commerce to the area perhaps?

  56. Jessie says:
    April 23, 2011 at 5:06 am

    …What do do imagine the structure along the island coastline a km or 2 directly east from ‘the ‘fort’ of Kilwa Kisiwana Island to be? A jetty?

    Looks like a dock, not a solid jetty, or there would be sand buildup on one side or the other.

    All in all, an odd place to be mapped and shown for a ‘fort’. The island is on a tidal river and the fort inland to the ocean?

    In researching this I’ve found the site described as a “fort” or “fortress”, and as a “jail”. “Gereza” means “jail” in Swahili, so I suspect that is the correct description. There’s a discussion of “gereza” here … you go on to say:

    I would think a slave trading depot. Not as Basil Davidson purports of the Portuguese trade in humans. I imagine for the Muslim (or Swahili) slave trade + collection point for the inland mineral trade/commerce to the area perhaps?

    Agreed, and the description of it as a “gereza” supports your hypothesis.
    w.

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