Well, I still got the same results, but then, thinking about it, I get the same result with any planet that doesn't revolve around a sun.... I guess it's logical, but that means realistic climate changes can only be simulated in a solar system, never with only a planet... Am I right? Edit: all continents are covered in ice within a year's time.
Edit2: I misread the OP. This happens to me when I pump more co2 in, like 3x 2010 levels.