The author calls this "ancient" but the reality is the Arctic is no warmer now than at any other warming period in the past and this is not "ancient" carbon trapped form millions of years as they try to suggest.
But the point is most of it is being reabsorbed by the land.
FTA:
By studying sediment cores, the team found that large amounts of carbon from land are preserved in the seafloor. They also discovered that marine microorganisms behave like selective eaters, favoring fresh carbon from the ocean over older carbon released from permafrost. The findings were published in Nature Geoscience.
So microorganisms don't want the stale stuff and let it return to the Earth from which it came.
This research only looked at one island - hardly a statistically significant sampling.
But it suggests that what the Climate Change people have been peddling is twaddle; the sea floor picks up most of the excess carbon, as it always has.
We've had numerous warming periods that are warmer than now and we've not had a problem with spiking CO2, except later (as much as eight hundred years).
Once again nature shows herself to be several steps ahead of the climatologists, who think models represent reality.