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So there are two ways that the rise in sea level can affect people on the ground.
One is in low lying areas where you have the surface is very close to sea level.
There's a gradient in the water in the soil between fresh water that
comes from rainfall that can be used to feed the crops versus salty water,
that's sort of encroaching from the ocean.
And if you raise the sea level and
you bring the salty water too close to the surface, you can poison the agriculture.
So there are islands in the Pacific low lying islands that are making
plans to evacuate in the coming years,
because their agriculture is no longer possible, because of salt encroachment.
But a more dramatic impact of sea level rise comes during storms,
which tend to pull the sea level up.
It's called a storm surge.
It's like a really high tide that sort of follows a hurricane.
And so Hurricane Sandy, for example,
in New York was at a sea level higher than it would've been if
the sea level hadn't been rising over the last few decades.
And what's important is when the sea level crosses some critical height where
suddenly, it can spill over a levee or flood the subways or something like that.
So the rise in the background sea level coupled with storms that
seem to be increasing in their severity, which we'll talk about next can
sort of multiply each other to exacerbate this impact of rising sea level.
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