Tuvalu

On with the boring. Disclaimer: this is nit-picking, for the question “is Gore accurate?”. On the wider issue, I’m with the judge and with RC: Gore is basically correct. First off, its not really Tuvalua, its vaguer: “that’s why the citizens of these Pacific nations have all had to evacuate to New Zealand” is what the judge has him saying (p 26). Which also fits a transcript NJ kindly pointed me to. Just in case we’re in any doubt as to the tense Gore is using, the book rather helpfully has a double page spread with large letters for the hard-of-reading (p186-7) saying “Many residents of low-lying Pacific islands have already had to evacuate their homes because of rising seas”. The picture under the words, though, is captioned high-tide at Tuvalu, so we’re back to pinning this on Tuvalu. I’ll come back to the context at the end, but just for now note that this is in the context of sea level rise – you’re not allowed to let Gore cop out by blaming it on storminess.

But “have already had to evacuate” is b*ll*cks. We all know that sea level has risen at about 2 mm/yr over the 20th century, which equates to about 20 cm. Thats a global average. The rise at Tuvalu is, if anything, somewhat less.

How then do we reconcile this with all the nice people who support Gore on this? Lets pick out Inel (because she is nice) and Tim Lambert (because he is an evil psycho-killer; don’t worry folks, thats a compliment).

Also, please read NJs nice comment.

Tim uses http://www.loe.org/shows/segments.htm?programID=06-P13-00013&segmentID=6. And his quote (cut) is “Seeing themselves as climate refuges some Tuvalans are already leaving their islands, moving their communities to higher ground in a new land… New Zealand did agree to take 75 Tuvaluans a year as part of its Pacific Access Category, an agreement made in 2001.” This is, of course, only news reporting, and we should all by now know not to trust anything the media tells us unless its corroborated; *especially* if its heart-breaking and newsworthy tales of climate refugees. What other possible explanations could there be? Well, they may fancy a one-way trip to a first world country? Not entirely impossible.

In fact that story tells us that the changes have occurred over the past 20 years. Thats about 4 cm. It will take a lot to convince me that 4 cm of sea level rise will force evacuation. Storm surges and tides are obviously much larger than that. But the story also says “Gauges in Tuvalu indicate the sea has risen an average of five and a half millimeters per year in recent years. That’s consistent with average worldwide sea level rise.” No, it isn’t. Worldwide is more like half that. “Over 1950 to 2001, the relative rate of sea-level rise at Funafuti[, Tuvalu] estimated from the reconstruction is 1.6 ± 0.5 mm yr− 1.” say Church et al. (with a sideswipe at “dowsing” Morner), so that 5.5 mm/yr is distinctly dubious (a short-term fluctuation, perhaps?).

It would be interesting to see quite what NZ agreed, but from this its unclear that the 75 are related to SLR anyway.

What about Inel? Well… sorry, but this is one of those moments when one says, yet again: “repeat after me: I must not believe everything I read in the newspapers”. Even nice one like the grauniad. Sometimes they simply lie to you, other times they will happily embroider, particularly when reporting science they don’t understand (I somewhat apologise to Inel for speaking to my elders and betters like that, especially since Inel knows it already, but I’m really talking to the rest of you :-).

Her first, headed “TUVALU: Going down”, ostensibly about “a victim of global warming”, includes “Fifty hectares of Tuvalu disappeared into the sea during the 1997 storms”. Well du-ooh, *yes*. Its the storms. Its not the rising sea level. There follow some rather unconvincing predictions. Their far-future is probably iffy, but there is nothing there about their present-day problems. The second is even worse: “FAREWELL TUVALU… A group of nine islands, home to 11,000 people, is the first nation to pay the ultimate price for global warming.” Predictably enough, nothing in the story justifies that start. The third (3 ==4?) is much the same: “This year alone in 1997, Tuvalu was devastated by three tropical cyclones; the firs two in March – Gavin and Hina – and more recently Keli.” – its the storms again.

Conclusion: I can see no evidence that Tuvalu is suffering because of past to present sea level rise. The evidence of the rate of SLR is strong evidence that there has been little effect; the few newspapers stories to the contrary are vague and anecdotal and clearly cannot be relied on. I can see some evidence for storm damage (but no evidence that this has increased due to GW; and anyway, as noted at the start, Gore isn’t talking about storms). Worrying about future rises probably makes sense.

And lastly, the context. From the transcript: “The Second Canary: Antarctic Peninsula Sea Ice… break up of ice shelves along the Antarctic Peninsula… When the floating sea-based ice cracked up, it no longer held back the ice on the land. The land-based ice then started falling into the ocean… That’s why the citizens of these pacific nations had all had to evacuate to New Zealand.” This piles error on assertion on uncertainty. Firstly, SLR from the Antarctic peninsula is at most a small fraction of the global total. Second, the “holding back” stuff is uncertain. Third, I don’t think we could confidently assert that the overall contribution of the peninsula is to raise sea level.

Comments

  1. #1 cce
    2007/10/13

    To avoid controversial scientific and political jargon, we will say that people “left” the island because their homes were being “flooded” on a daily basis.

    Tuvalu is also featured in Tom Brokaw’s “Global Warming: What You Need To Know,” which is a pretty good documentary. The islands’ meteorologist says (through Brokaw’s narration) that high tides usually came in January or February but now they come for “almost half a year,” and they’re more “severe, sustained, and widespread.”

    Whether it is sea level rise, unusual weather, erosion, or all of the above, the result is that the islands are swamped. People left. Expect this to be more common in the future.

    Veoh.com has the Brokaw documentary, BTW.

    ****
    Critique my presentation on climate change skepticism here:
    http://cce.000webhost.org

  2. #2 Brian Schmidt
    2007/10/13

    I think you’re jumping ahead of the evidence, William. Gore may be guilty of the same thing, but jumping ahead of the evidence isn’t the same thing as proving you’re right or he’s wrong.

    1. The LOE segment doesn’t say the changes have only happened in the last 20 years; it says that one particular family noticed changes in the last 20 years.

    2. NJ’s link says likely 8 cm rise from 1950-2001, maybe another .5 cm since then. If we extrapolate back 50 years, you get a rise of 16 cm over the last century. I suggest that on an island with a max elevation of approx. 100 cm, it’s reasonable to conclude the rise plays an important role in the evacuation of a small percentage of the population, <10%.

    3. Even if you accept that the only part of the 16 cm rise that we’re allowed to think about is the last 4 cm, I think you can’t dismiss it as causing evacuation of a small percent of the population. I don’t know what effect it would have on salt water intrusion to what must be very limited groundwater – is it more than 4 cm in some areas? What did it do to surface vegetation that helps hold the island together?

    4. You can’t fully split storm damage from sea level rise. SLR makes storm damage worse.

    5. “no evidence that this [storms] has increased due to GW.” I don’t understand this – I know on the global level there’s evidence of increased storm intensity, but not enough to have created a consensus on the issue.

    6. I don’t this this statement, “I can see no evidence that Tuvalu is suffering because of past to present sea level rise,” is defensible against a 16 cm rise on an 100 cm high island.

  3. #3 barry
    2007/10/14

    Monthly comparisons of sea levels are available here.

    http://www.bom.gov.au/ntc/IDO60101/IDO60101.200708.pdf

    Tuvalu’s sea level has risen at an average rate of 5.8mm per year for the last 13 years. Perhaps the end effects are still significant, and during that time there was a period of significant drop in sea level. No matter how you look at it however, it is a significant change for such a low lying island. Not only are they having to put up with higher tidal and storm surges, but water supplies become increasingly brackish.

    As with all these things, you can’t say that it is all caused by AGW, nor is sea level rise the sole reason that people want to leave. Does it justify Gore’s statements? Probably not completely, but nor can you call them wrong.

    [Interesting to see that table of SLR. Note the caution on it: "Please exercise caution in interpreting the short-term trends in the table below" -W]

  4. #4 Douglas Coker
    2007/10/14

    In my summary of the Tuvalu issue I said. “So maybe it is difficult, or indeed impossible, to find examples of small islands which have been evacuated completely. But evacuation – seen as a process as opposed to a single event – is clearly under way.”

    You could nitpick over the definition of “evacuation” but I think that will be my party piece on this – for the moment.

    The link to the whole thing is below.

    Douglas Coker

  5. #5 Lassi Hippeläinen
    2007/10/14

    IMHO Tuvalu shouldn’t be paraded as an example of the problems created by global warming, because there are several reasons for the current situation. The AGW denialists will be happy to point out the other reasons, just to divert attention from AGW.

    First: the relative sea level changes locally. Mareographs on remote islands aren’t reliable, because the islands are… vertically challenged. The sea bottom is very thin, and the islands move up and down continuously. I won’t go into the details, but the trend is to go down, because the magma under the island gives way, and the mareographs report it as rising sea. OTOH some Pacific islands rise, because the weight of a nearby volcano forces the surrounding sea bottom to bulge up. And then there are some plate tectonics going on… (Maybe you could recruit your resident geologist at Highly Allocthonous to elaborate.)

    Secondly: people aren’t moving away just because of rising sea. Most Pacific islands are overpopulated. Tuvalu’s density is at urban level (almost 500 per km2). There is no higher ground to move to; everything is already occupied. The families are large, and the only option available for younger siblings is to leave the islands.

    And then there is the third issue, the rising sea level. The main danger isn’t drowning. The increase of ground water salinity will make low atolls uninhabitable long before they are inundated.

    It’s a pity, really. I visited the South Seas in 2005, and found out that the Polynesians are the friendliest people anywhere. I wish them no harm. It’s ironic that people in the Bush Administration, who claim to be Good Christians, don’t care about people who are the most honest of Christians on earth.

  6. #6 Tim, Psycho Killer
    2007/10/14

    The LOE show played quotes from a Tuvuluan who said that he had left because of rising sea levels. Maybe he was mistaken, but that’s what he said.

    [People say many things that neither you nor I believe. In this case, they have a clear motive for saying them, and the evidence for what they are saying is weak to non-existent -W]

    The book has a bit more context: “This is one of the reasons sea levels have been rising worldwide, and will continue to go up if global warming is not quickly checked.” So it’s sea level rise in general, not just from Antarctica. And it’s future sea level rise as well.

    Plus, see < http://initforthegold.blogspot.com/2007/10/eight-errors-and-editing-error.html“>Michael Tobis.

  7. #7 Luke
    2007/10/15

    Spectacular effect of king tides on Tuvalu – it’s pretty low.

    http://www.tuvalu.tv/tiki/tiki-browse_gallery.php?galleryId=1

    Lots of traps in measuring sea level tides in these places – BoM adjust for tectonic movements with GPS.

    http://www.bom.gov.au/oceanography/projects/spslcmp/reports.shtml

  8. #8 Hank Roberts
    2007/10/15

    Gore’s mistake seems to have been stating this before those pictures were taken. If he’d had them in the slideshow, the Judge would have had to think twice about the standard of proof. Who ya gonna believe, the climatologists who say it’s not proven, or your lying eyes?

    [Why? Do you think those pix show 20 cm of SLR or a high tide? -W}

  9. #9 outeast
    2007/10/16

    I’m not really planning throwing my weight behind Gore on this, not least because – as WC rightly says – his actual words were demonstrably wrong.

    That said, the Tuvalu national website is pretty emphatic on fears there. A syndicated article there (http://www.tuvaluislands.com/news/archives/2005/2005-02-22_tmta.htm) refers to a number of documented impacts of SLR – primarily corruption of the water table and elevated peak tides. It’s worth a look, I guess.

  10. #10 Adam
    2007/10/16

    Firstly, I’d follow “outeast” on his/her caveat.

    However those pictures of flooding are obviously caused by a high tide…but have high tides caused that amount of flooding periodically over the last 100 years? Or is it a relatively recent phenomenon?

    I assume that Sea level is defined as an average point between high and low tides, or some “normal” state? Either way, one of the factors that influence the tide height will be the “base” sea level, surely? So does the high tide increase in relation, eg the sea level is 20cm higher so the high tide is, or does high tide level increase by a larger or lesser amount?

    If 20cm of seal level is not enough to cause such a change in high tide effects, then what has caused them (assuming they are relatively new)?

    Finally, when the island does eventually get inundated (whether tomorrow or next century), won’t it be during a high tide? Even if the water recedes to leave the island exposed, it will then be uninhabitable (ignoring water quality etc.).

  11. #11 truth machine
    2007/10/26

    Spend your time doing something other than fueling the deniers with such silly nit-picking,

  12. #12 Hank Roberts
    2007/11/11

    Au contraire, nitpicking is the fundamental primate social activity, we might as well get good at it.

    William, do you think there’s anything new in the measures of speed of glacial ice movement above places where the sea ice broke up in Antarctica recently? I gather this is being watched fairly closely and you’d probably know details.

    [I think you mean ice shelves, not sea ice. There is evidence of speed ups along the Peninsula - but this is a narrow region of comparitively steep ice and probably atypical of elsewhere. Other regions... maybe; but hard to separate variations from trends. We know that ice streams have started up and stopped for no apparent reason in the past -W]

  13. #13 Hank Roberts
    2007/11/11

    Here’s one — noting that they don’t have good baseline information:

    http://adsabs.harvard.edu/abs/2007JGRF..11203S29P

    Widespread acceleration of tidewater glaciers on the Antarctic Peninsula
    Pritchard, H. D.; Vaughan, D. G.
    Journal of Geophysical Research, Volume 112, Issue F3, CiteID F03S29 06/2007

    [Ha indeed, I told you it would be the Peninsula. And by our own folk. 0.16 mm/yr is certainly something, but not enough to make people sit up and take notice -W]

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