[–] realneil 1 point -1 points 0 points (+0|-1) ago (edited ago)
Because it could trigger a runaway greenhouse effect. Systems tend to find a equilibrium and we are not sure where it may settle if we cause a shift. It isn't that 2 degrees is bad it is because it may lead to something like Venus.
As the modelling has shown, we just don't know.
[–] SJWs_R_FAAAGS ago
Why you ask?
Fear.porn