There are some lessons from the past that make this particularly worrisome.
one is a trace of sea level through time
through the last deglaciation.
Sea level was 120 meters lower during the last ice age.
And when it rose to form the interglacial world that we live
in today, it didn't just rise in a smooth way, but it seemed
to go in pulses.
And in particular, there was this one interval called Meltwater Pulse 1A.
Which was a huge amount of water, a very large change in sea level
in a very short time, and glaciologists
aren't even sure where this water came from.
Another class of events from the paleo record is called Heinrich events.
What's left behind today are
layers of pebbles in the sediments of the Atlantic Ocean.
They're much too big to have
been blown there by wind.
They must have been carried in ice.
They are called ice-rafted debris. At various specific times
during the glacial time, the Laurentide ice
sheet, in North America, seemed to just collapse and dump
vast armadas of icebergs, carrying
these little pebbles into the Atlantic ocean.
They made layers of ice-rafted debris, that we find today.
The trouble is that models of ice sheets
Can't generate this much ice-rafted debris.
It's clear that ice sheets know a trick
or two about melting that we're only now figuring out.
And if anything, the models that we have for the
ice sheets and their response to climate are probably too sluggish.