Even the case you cite here, with 1.6 degrees of warming, looks very dangerous to my eyes.

Yes, 1.6 is getting dangerously close to the 2 degree 'tipping point' touted by many in the Climate Science field. A key component of the Feedbacks is just how the Tundra reacts to warming conditions ie does it thaw dry or wet.

Note that the 2 degree tipping point is measured from 1900, not from the higher 1990 reading.

You are refering to which page of the report?

I was referring to the previous comment.