[arcticPeril]

Maybe I'm missing an important detail about the lifecycle of arctic ice, but...

If the arctic ice contains plastic particles...

And the particles are man made...

And man has only been making small plastic particles for roughly 100 years...

That would mean that the arctic ice was, at some point in the recent 100 years, ordinary sea water polluted with small plastic particles.

If this ice... was sea water in the recent past, then it must be superficial ice.

If superficial arctic ice is young enough to contain plastics, and is now melting, then this marks the return of sea water from as recent as 50-100 years ago...

If melting polar ice, polluted with plastics, is a new and disturbing event, then...

Does this mean that this is the first time polar ice of that age is melting?

If 50-100-year-old polar ice is only melting just now, for the first time, then, in terms of rising sea levels, does this mean that sea levels have, thus far, only risen to their state as they existed at the end of the 19th century?

Or, is it that the arctic polar ice cap completely melts every summer and refreezes every winter?

If so, then won't a similar amount of plastic be recaptured when the arctic polar ice cap refreezes? Or are we now fretting at the idea that the arctic polar ice cap will fail to refreeze?

And doesn't that mean that 2 years ago, and 10 years ago, the polar ice cap was capturing just as many plastic particles when it refroze?

And if this plastic-bound ice has also melted during the past few summers, didn't it redistibute its captured plastics back into the ocean?

If the arctic ice cap is (or was) trapping large quantities of man-made plastics, then the sea ice doesn't seem to be the real story here.

The real story seems to be the horrendous amount of plastics in the ocean. The arctic polar ice cap, on the other, hand seems to be an unfortunate additional detail.

[flavor8]

Yes it melts, yes it refreezes. But more is melting each summer, and less is refreezing each winter. That's why there's excitement about opening of the northwest passage - shipping and oil drilling in the arctic that wasn't previously possible.

http://nsidc.org/arcticseaicenews/files/2014/05/Figure3.png

http://nsidc.org/arcticseaicenews/

http://www.motherjones.com/environment/2013/08/climate-chang...

http://www.scientificamerican.com/article/opening-of-northwe...

[omilu]

"That's why there's excitement about opening of the northwest passage - shipping and oil drilling in the arctic that wasn't previously possible."

That's a glass is half full way of looking at it!

[flavor8]

I was leaving the obvious unsaid; the shipping/resource-exploitation aspect isn't as well known. I guess we'll be finding out what happens when an oil spill gets caught up in arctic ice in the next decade or so.

[jmpe]

Yes, you're missing an important detail about the lifecycle of arctic ice.

Multi-year ice is about 6 years old. There's no 100 year old ice there. Every year it gets slushed, reaches a minimum around September and builds up again. The minima are dropping, btw. Both in extent as in volume.

[refurb]

There is no 100 year old ice out there"

Where are we getting the air samples to determine what CO2 levels from? I thought it was from bubbles trapped in ice that is 100+ years old.

[jimworm]

The Antarctic, Greenland, other glaciers.

[001sky]

Great point. Glaciers on land are diffrent. There are also some ancient/long-lived ice formations in the south pole (also land/locked). I believe these are more like frozen freshwater lakes than glaciers (mobile, compacted snow etc).

[jmpe]

You misquoted me, please re-read it.

[anonymfus]

Amount of old ice in Arctic, 1987-2013:

http://www.youtube.com/watch?v=H-BbPBg3vj8

[marcosdumay]

Even when it had permanent areas, floating ice exists in equilibrium. If you add ice on the top, the bottom melts due to pressure.