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'Sinking' Pacific Nation Tuvalu Is Actually Getting Bigger (phys.org)

Posted by BeauHD on from the defying-all-odds dept.

mi shares a report from Phys.Org: The Pacific nation of Tuvalu -- long seen as a prime candidate to disappear as climate change forces up sea levels -- is actually growing in size, new research shows. A University of Auckland study examined changes in the geography of Tuvalu's nine atolls and 101 reef islands between 1971 and 2014, using aerial photographs and satellite imagery. It found eight of the atolls and almost three-quarters of the islands grew during the study period, lifting Tuvalu's total land area by 2.9 percent, even though sea levels in the country rose at twice the global average. Co-author Paul Kench said the research, published Friday in the journal Nature Communications, challenged the assumption that low-lying island nations would be swamped as the sea rose. It found factors such as wave patterns and sediment dumped by storms could offset the erosion caused by rising water levels.

9 of 152 comments (clear)

  1. Re: An interesting prospect, but also an edge case by Anonymous Coward · · Score: 2, Informative

    Sea levels that have been rising at the same slow consistent rate since the end of the last ice age....

  2. Re:An interesting prospect, but also an edge case by pots · · Score: 4, Informative

    Did you look at your link? A linear regression on the annual mean sea level gives an increase of 3.35mm/year. That's huge. Consider that the average elevation in Tuvalu, the whole country, is 2 meters.

    You're right about the peaks being worse than the mean, but the mean is bad enough.

  3. Size doesn't matter by neonfrog · · Score: 5, Informative

    If the ring is growing in thickness because coral is being dredged from outside the ring and then deposited on the inside of the ring by more frequent king tides that wash right over the ring, then perhaps those living right on the ring don't care about the size so much. They may care more about their thin soil being lost, salinated, and replaced by coral beach. Yes, having more surface area allows for more mitigation measures to be tried, but it is still a hard battle being fought because of sea level rise.

    --

    I'm thinking about it, therefore I might be.

  4. Coral reefs are alive by Hentes · · Score: 4, Informative

    These islands don't happen to be just above the water by pure chance, but because coral reefs grow until they hit the surface and then stop. When the sea level rises, the reefs will grow to match it.

    1. Re:Coral reefs are alive by swillden · · Score: 5, Informative

      These islands don't happen to be just above the water by pure chance, but because coral reefs grow until they hit the surface and then stop. When the sea level rises, the reefs will grow to match it.

      Eventually. But coral reefs grow very slowly, so it could be that rising sea levels will outpace reef growth and the island will sink for a few thousand years, then reappear. Also, it may take time for corals to adapt to rising temperatures and declining pH levels, further delaying reef growth.

      --
      Note to ACs: I usually delete AC replies without reading them. If you want to talk to me, log in.
    2. Re:Coral reefs are alive by Anonymous Coward · · Score: 2, Informative

      Yes, but it depends on the rates. Reefs also drown in such settings if they can't keep up with the pace of sea level rise or subsidence. There are many examples of seamounts (peaks below sea level) with coral reef deposits on top of them that are hundreds of metres below where the reefs can actually grow anymore. These are examples of situations where the seamount used to be an ocean island but sank beneath the waves faster than the corals could grow upwards.

      An additional factor is coral bleaching events and ocean acidification, both of which might discourage coral reef growth rates.

    3. Re:Coral reefs are alive by jhecht · · Score: 3, Informative

      What's going on is complex. Sand is being moved around a lot, as usually happens. Look at the smaller islands in Figure 3 of the (open-access) paper and you can see the above-surface part of small islands actually moves around. The sand-only islands are shrinking on average, but those with gravel are growing, probably because they catch sand being washed around. The living reefs are growing. Overall, it's encouraging for the near term, but the authors say it is not clear if the islands can continue to maintain their sizes with the faster sea level rise of 7.4 mm/year expected in some future scenarios.

  5. Re: An interesting prospect, but also an edge case by riverat1 · · Score: 5, Informative

    No they haven't. In the last couple of thousand years there's been a slight drop in sea levels. Until about 1900 that is when sea level rise has been consistent and accelerating. Here's an interesting article on SLR over the past several thousand years.

    Sea level isn't level-Ocean siphoning, levered continents and the Holocene sea level highstand

  6. Correction for You by ytene · · Score: 3, Informative

    I'm not a US citizen, so US party politics is not something that matters a great deal to me. I wasn't sure if there were documented facts concerning debt levels and US Presidents, so I went digging and came up with this:-

    https://www.thebalance.com/us-...

    It's a single source, so of course could be complete hogwash, but it's a start. According to the records there, every single US president all the way back to Herbert Hoover [directly before Franklin D. Roosevelt] added to the US Debt.

    Unfortunately, even these figures don't tell the whole story, because we have to consider both debt and deficit, in which the former is the amount the US owes, and the latter is the rate with which the former is changing.

    I make this distinction because, in recent memory, Bill Clinton has been the only US president who has actually decelerated the increase in US national debt. When he left office [IIRC] he did so leaving his successor, George W. Bush, with a tiny budgetary surplus. It's also instructive to look at the scale of the change in the debt position between Presidents. For example, George H.W. Bush left office with a national debt 54% greater than the one he inherited. Bill Clinton had trimmed that to a 32% increase. George W. Bush doubled-down on his Father's spending policies and managed a 101% increase in national debt. In the case of the two Bush Presidents, the increases were likely driven mainly by military spending to support the wars that they started.

    Now, I'd absolutely have to agree with you if we look at Obama's record. He added $7.917 trillion to the US national debt, a 68% increase, which puts him somewhere between Bush Father and Bush Son and way beyond Clinton's record. However, it has to be remembered that Obama won office in late 2008 and became President in Januaru 2009. In other words, less than 6 months after the 2008 financial crash had really hit home.

    What Obama did during his 8 years in office was, in economic terms, kick the can down the road. These are unarguable facts - the record speaks for itself. The reason *why* this is the case is obviously going to be highly partisan and subject to fierce debate. But the fact remains that the chief reason that Obama's record on the economy stands where it does is simply because he inherited one of the worst financial crises in living memory from his predecessor. The damage was done during the 8 years that George W. Bush spent in office [with increased military spending and tax cuts]. Obama just papered over the cracks and kicked the can down the road.

    But the record is pretty clear - with the exception of Coolidge and Warren Harding [who served immediately before him] every US President from the First World War to the present day has added to the US debt.