The radon release from that up there is not a big deal at all in comparison to other things. Radon is everywhere and there isn't a vast amount of dangerouly high stores of it trapped in the ice. This won't effect peoples homes like radon normally does, because it's going straight to the atmosphere from the ice and not coming up through the soil like how radon normally gets into homes where it can cause risk.
Big FYI for this: Radon is heavier than air, but very readily stirs and mixes/drifts around, so it very quickly dilutes itself. Furthermore of why this article is complete hyperbole: Radon only has a half life of 3.8 days. So there's no vast stores of it on the verge of being released, anywhere. 100 cubic meters of the gas (which breaks down inside the ice as well) would only amount to having like 7 cubic feet left after a couple weeks time. Literally a non issue. Doubly so considering the other things being released from the ice.
-Former Haz Mat Tech.