Kind: captions
Language: en
The ocean’s rising a few millimeters each
year right now.
That you may know, but it turns out that sea
level isn’t rising equally everywhere.
Here are four reasons why.
First, weather.
In particular, fierce storms and hurricanes
will be spinning up in different places on
the planet.
These storms have a major impact on regional
sea level extremes.
So it’s not just the gradual rise of global
sea level.
You have these large storms that give you
your flood times on top of it.
And so if you change the storms—if they
become more intense, if you increase their
frequency­­—these extremes in flooding
will have a larger impact.
Second, the ocean has a natural tilt.
There’s a drop in height while you’re
crossing the Gulf Stream.
It’s over a long distance – you’re not
gonna fall off a cliff as you cross the Gulf
Stream, but it’s on the order of several
feet.
It’s the Gulf Stream itself that causes
the tilt.
Faster currents mean more tilt.
Slower currents mean less tilt.
And if you melt ice in the ocean and add more
freshwater, this could impact the strength
of the Gulf Stream and the angle of that tilt.
So you can get changes in sea level locally
just by redistributing this water.
Third, as ocean water gets warmer due to climate
change, that water is going to expand.
You don’t need to add mass for this to happen—if
you just warm the water, you’ll expand it.
And because the whole ocean won’t warm by
the same amount, sea level will rise differently
depending on where you are on the planet.
And finally, there’s gravity.
The more mass something has, the greater the
gravitational force it exerts.
Right now, the ice caps at the poles are massive,
which means they pull ocean water towards
the Antarctic and the Arctic.
Once you start melting ice either in Antarctica
or in Greenland, you are reducing the gravitational
attraction that these ice sheets exert on
the ocean.
This means that sea level will drop close
to Greenland, the same for Antarctica.
But now this water has to go somewhere – so
it will rise in the tropical regions, in the
equatorial regions.
We still don’t know how all these forces
will play out.
But one thing is clear—some areas will take
a harder hit than others.
Hit!