Unfortunately, net positive feedback loops for climate are clearly evident in the geological record. A great presentation of the evidence is in Hansen's Storms of My Grandchildren.
He also says it's basically impossible for the Earth to reach a Venus-like state. But we could easily get runaway warming sufficient to add several extra degrees.
He also says it's basically impossible for the Earth to reach a Venus-like state. But we could easily get runaway warming sufficient to add several extra degrees.