alt Hacker NewsI've never been able to decide whether it is or not. I'm still vaguely scared of the clathrate gun, permafrost releasing extra CO2, and phytoplankton shrinking under ocean acidification so we can't have as much oxygen as we're accustomed to.
Edit: one of those crossfire situations where the downvotes could be coming from either direction. I'm going to assume they mean "don't be scared".
I don't know who downvoted you, people treat this topic with religious zeal. Yes, basically all the arguments trying to claim that the influence of CO2 has positive feedbacks relies on cascades of things amplifying warming.
And that's certainly something to discuss, whether there exists a type of rube goldberg machine where higher levels of CO2 cause the permafrost to melt which cause even higher levels of CO2 which cause something else to release even more CO2, etc.
I certainly wont deny that such a sequence of events is possible, and it's worth studying. But on the other side of that you have basic physics, which shows that the warming effects go with the log of CO2. That really slows things down by quite a bit. It turns a doubling into an additive factor.
Now, could it be that the cascade of events is such that it overcomes the logarithm? E.g. that it is an exponential or super-exponential chain of events that would release exponentially more CO2. Uhh, maybe, but this is not something to try to terrify the population with. And it sounds extremely unlikely. So you need an extremely precarious set of assumptions -- or just deny physics outright -- to overcome Arrhenius' Greenhouse rule. Logarithms cover a multitude of growth sins.