It is very loose science. The creator, Joe Slayton, has dealt with this very question umpteen times. The basic science calculations are all there, but it should always be considered a suggestion. It does not take things like wind and water currents into consideration since it can't calculate those, and a vast amount of climate conditions are based of wind and water currents. Instead it uses, temperature, altitude and rainfall to calculate the climates which is only half of the calculations for a true biosphere.