Thursday, May 03, 2018

Low islands and climate change, revisited

Early in the life of this blog, I used to criticise the reporting of politicians and environmentalists claims about sea level rise being about to cause the more-or-less immediate demise of low lying Pacific islands.   The situation, when you looked at the details, was more complex, and this was hardly ever reported.

Move forward, and there was a recent report which climate ignoramus Andrew Bolt seized upon with glee - 
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 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.
I meant to comment on it at the time, because, I thought, a mere small growth in the area of a low lying island (caused by currents pushing around sand and ground up coral, I believe) tells us nothing about the habitability of the island.   The immediate problem with sea levels that I had seen on some documentary shows was the ground water becoming replaced with salt water.  

An article at Carbon Brief explains this well, and supports my hunch from earlier this year.  A new paper suggests that many low lying atolls will be uninhabitable due to the groundwater issue earlier than expected - perhaps by mid 21st century.

Not everyone agrees - it would seem that New Zealand (which was the source of the "Tuvalu is growing" study) has some scientists who are busy downplaying the issue.   (Given New Zealand's reputation as a lifeboat island for South Pacific islanders, one wonders if there is a bit of a motivation for such studies.)

So, I still think my early criticisms of media gullibility on the issue were valid;  just as my criticism of climate change denialist's complete dismissal of the very same issue is valid now. 

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