Thursday, September 25, 2014

Nikumaroro is Washing Away

I’m grateful to Ric Gillespie for sending me the image shown above.  He prepared it in 2006 by overlaying historical airphotos on satellite imagery of Nikumaroro, where we hypothesize that Amelia Earhart and Fred Noonan landed and died.

The portion of Niku that’s shown is the land unit called Ritiati and the adjacent Tatiman Passage.  Ritiati is the site of the colonial (1939-63) government station and village.  The areas marked in red represent land eroded away since the earliest good aerial imagery in the late 1930s.  The yellow areas are those that as of 2006 had experienced substantial overwash by storm surges. 

The succession of aerial images actually shows that the shoreline was relatively stable until the late 1980s, at which point overwash and resultant land loss seems to have taken off.  In the years since Ric prepared the image shown here, it’s continued.

The bottom line is that Niku is washing away.  This is what sea level rise looks like – not a gradual rise in water level as in a bathtub, but the removal of land in a series of minor catastrophic events.  The rising sea levels send salt water into the porous coral island; it displaces the freshwater lens that makes plant life possible.  The plants die and their roots stop holding the coral soil together.  Storms send waves farther and farther inland, eroding the land and further destroying the freshwater lens. The cycle continues and is amplified through time.

Soon or late – probably rather soon – we’ll lose Niku.  That will be tragic, at least for those of us who love the place and are fascinated with its history, archaeology, and ecology, and for its resident crabs, rats, and birds -- and corals and fish.  But what’s far more immediately tragic in human terms is the loss of similar atolls on which people live, and have lived for thousands of years – Tarawa, Majuro, and the rest.  Kathy Jetnil-Kijiner said it best, in her speech to the UN Climate Change summit in New York --

I only wish I could share her fierce optimism.

I've had arguments with my fellow TIGHAR Board member Skeet Gifford about the extent to which climate change is the result of human activity; I'll confess to being unsure, as I am about most things.  But whether we're much to blame for it or not, it's happening, and driving sea level higher.  We are going to have to do something about it -- at least to adapt to it.

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