That article doesn't say anything about how much methane is being released. The fact that it's happening isn't being disputed. The prediction that it will be catastrophic is.

Oh, it will absolutely be catastrophic if the Siberian tundra thaws. Have you seen the estimates for how much carbon is locked in the permafrost? It's more carbon than is in the atmosphere today. [1]

[1] https://nsidc.org/cryosphere/frozenground/methane.html

17 million tons of methane in 2013 and rapidly increasing. Source: https://en.m.wikipedia.org/wiki/Arctic_methane_emissions

So, is that a lot or a little? How much do cows produce? How much does human activity release? (Honest question; I don't know.)

It's estimated there's 1300G tons of methane stored in tundra.

1300 * 10^9 is about 100 years of 2020 CO2 activity.

13 * 10^6 is 100/1000 years of 2020 CO2 activity, I guess.