Actually I believe that it is a derivative natural right. 

To anybody who has read John Locke's 2nd Treatise the following passage should sound familiar,

"Nor was this appropriation of any parcel of land, by improving it, any prejudice to any other man, since there was still enough and as good left, and more than the yet unprovided could use. So that, in effect, there was never the less left for others because of his enclosure for himself. For he that leaves as much as another can make use of, does as good as take nothing at all." 

It is commonly referred to as the Lockean proviso and it applies to all natural resources not just land.

Any thinking person knows right off that this is the only truly just way to deal with natural resources.

As to when there is not "enough and as good" to allow any/all other/s to do likewise, a debt is immediately incurred to the commons. That is precisely why the PFD is a natural debt derived from taking more than enough and as good from the commons.