Runaway Ice Sheet

I have to present an article, “Recharge of a subglacial lake by surface meltwater in northeast Greenland,” to all the geology professors and majors and minors this Friday. Friday the 13th. Just my luck.

It’s been one of those weeks where everything just sort of falls apart. Our heater broke in the house, the laundry machine is leaking water all over the basement, the heater broke again, and then today the garbage disposal decided to fall apart and spray food everywhere.

But back to ice sheets and other catastrophes.

Ice sheets are weird. They are miles and miles of compact ice that flow and move, super, super slowly. It’s hard to wrap my head around. Ice moves and crawls and can fucking swallow mountains! It’s crazy. When I try to picture ice crawling, I visualize myself peaking under the ice and seeing millions of little feet taking tiny steps.

Glaciologists don’t fully know the intricacies of how ice sheets and glaciers move, their dynamics, especially when other factors, like a warming atmosphere, are messing with those known dynamics.

The paper talks about the discovery of a mitten-shaped basin on the surface of the Greenland ice sheet, and after the scientists did some data gathering for two years, they found out that climate change is making the Greenland ice sheet melt faster. Not good.

When the ice on the surface melts, it collects in lakes like the ones in the study. Ice sheets have a bunch of cracks and crevasses, and sometimes the surface meltwater, whoosh, rapidly evacuates into these cracks, now collecting at the bottom of the ice sheet.

We have lakes at the bottom of ice sheets (subglacial lakes), which is mind boggling, but so what?

When these subglacial lakes overfill, they catastrophically burst and flood the bottom of the ice sheet, flowing towards the ocean in circuits of subglacial channels. It’s kind of like a water slide. If you don’t have any water to rocket you down, you don’t move very fast–skin sticks to plastic and it’s an uncomfortable situation. But if there’s water on that slide, you’re going to rocket down.

The same thing happens with ice sheets. The water allows the ice to flow, almost glide, way faster that geologists thought before. And all that ice is flowing towards and into the oceans.

More warming in the atmosphere means more surface meltwater, which means more subglacial lakes, which means ice sheets will shrink and disappear rapidly. All those little feet at the bottom of the ice sheet are in a full-on sprint.

Shit.

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One thought on “Runaway Ice Sheet

  1. Good article, it’s so interesting (and scary) to think about! Who knew ice crawled?
    Thanks for sharing your thoughts. Geology rocks, and good luck on your presentation!

    Like

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