Well that is easy. The UN must pass a treaty declaring that no one can own Martian land or mineral rights. The entire planet must be preserved as an international sanctuary to prevent it from being exploited for profit.
It would be wrong to disturb the pristine environment of Mars and disrupt the natural evolution of that planet.
Gene Hunt will be needed to keep all the exploiters of space honest or sort of anyway.
http://www.youtube.com/watch?v=9unL2Jfj__U