Andrew Revkin

What became known about Antarctica and Greenland more is that its ocean temperature...

The seawater in and around and under these ice sheets, because it kind of gets under parts of Antarctica, is what's driving the dynamics that could lead to more abrupt change, more than air temperature.

Glaciers, these big ice sheets live or die based on how much snow falls and how much ice leaves every year.

And I was up on the Greenland ice sheet in 2004.

I've written about it forever since then.

It's the same amount of water that's in the Gulf of Mexico as if God or some great force came down and flash flows the Gulf of Mexico and plunked it up on land.

That's the ice sheet.

It's a lot of water.

That's 23 feet of sea level rise.

But you were not going to melt at all.

And the pace at which that erosion begins and becomes sort of a runaway train

is still not well understood.

That change from a manageable level of sea level rise from these ice sheets to something that becomes truly unstoppable or that has these discontinuities where you get a lot more all of a sudden, to me, it's in the realm of...

what I've taken to calling known unknowables.

Don't count on another IPCC report magically including science that says, aha, now we know it's going to be five feet by 2100.

Because learning, there's a lot of negative learning in science.

This may be true in your body of science too.

There's a guy named Jeremy Bassis, B-A-S-S-I-S, who wrote a paper about this West Antarctic, the idea that you could get this sudden cliff

breakdown of these ice shelves around Antarctica leading to rapid sea level rise.

He did more modeling in physics and it turns out that you end up with, it's a much more progressive and self-limiting phenomenon.