In this essay, I ask what conception of property rights best reconciles the often conflicting claims of liberal freedoms and ecological sustainability. I argue that environmental concerns demand a reformulation of property rights in land, but that other spheres of property rights can be left more or less intact. Using ideas derived from John Stuart Mill, I develop a landed property regime which combines public wilderness zones with good private stewards to preserve ecosystem stability over time. The argument proceeds in three parts. In the first, I contend that sustainability requires treading carefully with landed property, because nothing impacts the environment more acutely than the human use of land. While most proprietary rights are in transformed natural resources derived from the earth, only land rights apply to the planet itself. But greens are not alone in focusing on land rights; liberal political thinkers as diverse as Locke and Mill have recognized a qualitative difference between property and land and property in other goods. It thus seems we can poke at land rights without undercutting the whole institution of private property. The second part of the paper musters Millian ideas concerning landed property to help arbitrate the frequent conflicts between private property and the public good. In Principles of Political Economy, Mill argued that it would be 'the height of injustice' for private individuals to usurp land where the productive power came primarily from nature (as opposed to human labor). Considering the value of ecosystem services to human flourishing, 'injustice' pervades modern property rights. Mill argues for a public goods conception of property instead; land rights are 'instrumental'rather than natural rights. From Mill's arguments I draw three principles which together constitute the basis for a sustainable land regime that is still permissive of private property. From these principles I sketch an outline of what this regime might look like on the ground; a sustainable mix of private stewards and public wilderness that avoids state coercion for environmental ends to the furthest degree possible. I argue this regime adapts well to changing ecological conditions, minimizing the need for continual political tinkering. I conclude by demonstrating the fairly wide agreement this regime should command, from Hayek-style liberals on one end to radical greens on the other
