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And if you're waiting for Pacific islands to go underwater...

13 Nov 2019 | Science Notes

You'll be waiting a long time, again. It was reported last year that, despite the much-hyped alarm about small Pacific island states being submerged due to global warming-induced sea level increases, Pacific atolls had not lost any surface area in recent decades and in fact the vast majority had grown. Now the mechanism for this change is becoming clearer. According to a new study, the rising sea itself builds the islands up.

The scientists combined field work with lab-based simulations and showed that as waves overwash the gravel-and-sand land forms, whether due to tides, storms, tsunamis or anything else, they leave behind deposits that have built up to a meter of new land height on the studied islands in recent decades (which is quite a lot considering the islands are only a few meters above sea level to begin with). But wait, don't these authors know rising sea levels will wash the islands away? Well, yes they know that everyone thinks that, and they don't mind pointing out that it's not true (emphasis added):

"Low-lying coral reef islands are considered extremely vulnerable to the impacts of climate change.... Assertions of island vulnerability are based on outputs from flood risk models that simulate sea level rise on present day island topography despite evidence that many reef islands are highly dynamic landforms. Utilizing a physical modelling methodology, three experiment programs were undertaken to model gravel island morphodynamics in response to increasing sea level and changing wave conditions. Modelling outputs present new insights into the modes and styles of island change, primarily the first experimental evidence that reef islands can keep pace with sea level rise through island building driven by washover processes. Results suggest that many islands are less vulnerable to inundation than currently perceived and may endure on reef platforms despite sea level rise."

Once the scientists stopped assuming that the islands will just quietly get submerged under the seas, and looked at how nature actually builds these atolls, they realized that as the seas rise, the islands rise with them.

It's getting harder and harder to figure out where the climate emergency is hiding.

2 comments on “And if you're waiting for Pacific islands to go underwater...”

  1. I wouldn't mind 2 or 3 degrees of warming. Every summer my wife & I go to Nova Scotia. With a few degrees of warming I could fulfill my dream of spending summers on a tropical island. The only time one needs to worry about climate change is when there is 2 miles of ice in your back yard. Move south.

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