Sea levels are on the rise pretty much everywhere, but not
at the same rate.
There is new information coming out of the University of
Hawaii that suggests that in areas where the rise has been smallest, it can
accelerate quickly.
An example: In the 1990s, the North Indian Ocean didn’t rise
much at all. But since 2003 it is catching up—rising at twice the global rate.
That’s from a paper in the Journal of Geophysical Research,
written by a team including Philip Thompson, of the University of Hawai`i Sea
Level Center in the School of Ocean and Earth Science and Technology, and Mark
Merrifield, Eric Firing, Christopher Piecuch and Julian McCreary.
The changes are due to a combination of winds and water
temperatures.
“Wind blowing over the ocean caused changes in the movement
of heat across the equator in the Indian Ocean. This led to suppression of sea
level rise during the 1990s and early 2000s, but now we are seeing the winds
amplify sea level rise by increasing the amount of ocean heat brought into the
region,” Thompson said.
Hawai`i has similarly experienced less sea level rise than
the global average. And that could also come to an end with
faster-than-expected rising following the slow period. We reported on that last year in RaisingIslands.
Thompson called this a staircase effect.
“What we are learning is that the interaction between the
ocean and atmosphere causes sea level to rise like a staircase instead of a
straight line – starting and stopping for many years at a time. What we’ve done
here is described one stair, which will help us better understand and plan for
the future,” he said.
© Jan TenBruggencate 2016
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