Below the thunders of the upper deep;
Far, far beneath in the abysmal sea,
His ancient, dreamless, uninvaded sleep
The Kraken sleepeth: faintest sunlights flee
About his shadowy sides: above him swell
Huge sponges of millennial growth and height;
And far away into the sickly light,
From many a wondrous grot and secret cell
Unnumbered and enormous polypi
Winnow with giant arms the slumbering green.
There hath he lain for ages and will lie
Battening upon huge sea-worms in his sleep,
Until the latter fire shall heat the deep;
Then once by man and angels to be seen,
In roaring he shall rise and on the surface die.
—Alfred Lord Tennyson
A significant release of methane due to melting of the vast deposits trapped by permafrost and clathrate in the Arctic would result in massive loss of oxygen, particularly in the Arctic ocean but also in the atmosphere. Resulting hypoxic conditions would cause large extinctions, especially of water breathing animals, which is what we find at the PETM.
Is it “alarmism” to yell fire in a crowded theatre if the building is in fact on fire? And you’ve come to realize the basement is full of gasoline tanks?