Wanted: A REALLY big "twisty-tie"

From this article:

University of Calgary professor David Keith's idea involves making a gigantic, inflatable, sausage-like bag up to 100 yards wide and several miles long. The bag would be able to store more than 175 million tons of carbon dioxide –- the equivalent of about two days of current global emissions.

The giant bag would rest on the seabed about two miles below the ocean’s surface.

I hope the narwhals don't foil this plan.