replying to myself because I can't react to the dead poster anymore:

I don't have high hopes that data will reverse any of your prejudices, but here you go:

Most recent study of methane flux/storage in the ESAS:

http://rsta.royalsocietypublishing.org/content/373/2052/2014...

Arctic temperatures are estimated to rise 1.9x compared to global average:

http://onlinelibrary.wiley.com/doi/10.1029/2005GL025244/full

During HCO the arctic is estimated to have been 4-6C warmer than baseline (yearly average):

https://epic.awi.de/38441/1/Beierlein_2015_Holocene_page1.pd...

That's not all that much. We're now already at 400ppm CO2, and recent unmitigated projections to 2100 (538ppm) simulate an arctic yearly average of ~ plus 8C:

http://climatenewsnetwork.net/arctic-is-set-to-reach-13c-by-...

And that most probably doesn't take a positive methane feedback loop into account.

So, are you willing to play the russian roulette game with the arctic methane? The PETM boundary showed a global average warming of 5C, mostly from arctic methane at a time where there wasn't even a large ice shelf, so with significantly lower capacity:

https://en.wikipedia.org/wiki/Paleocene–Eocene_Thermal_Maxim...

That would be in addition to the CO2 induced warming, mind you.