This TED Talk features geophysicist Dustin Schroeder recorded live at TEDx Stanford 2017.

So I'm a radio glaciologist, and that means that I use radar to study glaciers and ice sheets.

And like most glaciologists right now, I'm working on the problem of estimating how much the

ice is going to contribute to sea level rise in the future. So today I want to talk to you about

why it's so hard to put good numbers on sea level rise and why I believe that by changing the

way we think about radar technology and Earth science education, we can get much

better at it. So when most scientists talk about sea level rise, they show a plot like this.

This is produced using ice sheet and climate models. On the right, you can see the range of

sea level predicted by these models over the next hundred years. For context, this is current sea level, and this is

the sea level above which more than 4 million people could be vulnerable to displacement.

So in terms of planning, the uncertainty in this plot is already large. However, beyond that,

this plot comes with the asterix and the caveat, unless the West-Anarduk

ice sheet collapses. And in that case, we would be talking about dramatically higher numbers.

They'd literally be off the chart. And the reason we should take that possibility seriously

is that we know from the geologic history of the Earth that there were periods in its history

when sea level

rose much more quickly than today, and right now we cannot rule out the possibility of that

happening in the future. So why can't we say with confidence whether or not a significant portion

of a continent scale ice sheet will or will not collapse.

Well, in order to do that, we need models that we know include all of the processes,

conditions, and physics that would be involved in a collapse like that.

And that's hard to know because those processes and conditions are taking place

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