If John Locke were alive today, he would be an environmentalist!

John Locke, a famous libertarian philosopher, is well known for his labor theory of land ownership. This theory, and similar theories, are very popular among people who either think the the government should grant ownership of land in a non-arbitrary fashion (other than by simply selling deeds to the rich), or else that the government should have nothing to do with land ownership at all. The theory basically first starts with the axiom that you own yourself, and then proceeds to conclude that since you own yourself, you also own the fruits of your labor. When you mix your labor with land, e.g. in farming it, then, as an extension of your right of self-ownership, and the rights to the fruits of your labor, you gain ownership of a sort of the land, so that you may, for example, enjoy the harvest from the seeds you sowed. This is also often referred to as homesteading theory.

However, in Locke's theory, there were limitations on this right. For example,

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. Nobody could think himself injured by the drinking of another man, though he took a good draught, who had a whole river of the same water left him to quench his thirst. And the case of land and water, where there is enough of both, is perfectly the same.

—Second Treatise of Government, Chapter V, paragraph 33

 So, in this theory, while the homesteader may take some land for the purpose of a farm and house (or whatever), the homesteader may not be so greedy as to take so much as to deny others the same opportunity.

Now, if you perform hydraulic fracturing and pollute the whole darn watershed, you are not fulfilling the condition of leaving the water in as good condition as nature left it. There is a common right to land, air, and water, and while a simple small organic farm isn't likely to have any effect on the right of others to hunt and gather nomadicly or start their own small organic farms, particularly in a situation where there is plenty of land for everyone, such as a frontier, there is no right of pollution, or if there is, it must be cleaned up before it returns to the commons. (For example, a factory might use water, and dirty it in the process, but if it purified the water to at least as good as it was found in nature before returning it to the watershed, it could be alright. Additionally, small amounts of biodegradable pollution probably aren't a huge deal, since nature would handle cleaning it up, although it could depend on the situation.)

John Locke probably didn't have to worry much about pollution in his era, but I believe that if he were alive today, he would be an ardent opponents of polluters who damage our shared air and water resources. Which is ironic, given how many supposed libertarians cite their act of homesteading as justification for doing whatever they want on their property, including engaging in actions which pollute the whole watershed. And as for libertarians who cite a simple government deed as justification for doing what they want with the land, without considering what gives the government or the seller what gives them the right to sell said land to them, yet still don't want the government or anyone else preventing them from polluting the whole watershed simply because "I bought/inherited it, therefore it is mine", well, really....