Because there are vast quantities of methane under the permafrost and if they escape to the atmosphere the temperature will rise by a lot.

By how much? Any serious analyses online about this?

What would a runaway greenhouse effect realistically look like? Venus?

You can find a lot of information in threads that have been discussed here:

https://hn.algolia.com/?query=permafrost&sort=byPopularity&p...

Sorry, not browsing through hundreds of articles about all sorts of things being found in permafrost. Any direct links to your particular doomsday scenario?

Doesn't Methane burn? Maybe another energy source for the future...

Thanks - interesting read. But it is still just one of many doomsday scenarios. I've already survived several of them (for example the hole in the Ozone layer and global nuclear war), so I am vary of getting depressed over yet another gloomy projection.

Of course bad stuff can happen, no question.

From the article it sounds to me as if there is a lot of Methane to go around. Maybe we should use it up, and use the energy to power air conditioning and growing food in mines and wherever. That would already solve two of the scenarios in the article - unworkable climates and food shortages.

Diseases also seem treatable, and the article mentioning bubonic plague is rather reassuring. We have antibiotics now to treat that, and vaccines against many old scourges.

I thought CO2 is mainly an issue high up n the atmosphere. Presumably on the ground, it would also help plants grow, which would in turn use it up.

I'm just saying, things might turn out different than expected.

Maybe in general, it simply is impossible to prevent change in the world. A large fraction of the doomsday scenario addiction of mankind might simply be fear of change.