The harms of climate change are now well documented, from rising sea levels to destructive wildfires, severe flooding, and now the strongest El Niño on record. Yet classical liberals have often criticized proposals addressing this threat as impractical, costly, and/or beyond the legitimate scope of government power. We engage the latter critique by turning to John Locke’s writings. Locke is both a proponent of limited government and profoundly influential on liberal democracies. He argued that government exists solely to enforce natural law, and in doing so, it protects life, liberty, and property. While Locke presented the earth’s resources as existing to be exploited, he crucially limited property acquisition, arguing that natural law prohibits spoilage and requires we leave “enough and as good for others.” We argue that because these caveats are part of the natural law, governments are obligated to take comprehensive action addressing climate change.
In recently published research we demonstrate that comprehensive government action to combat climate change is compatible with John Locke’s conception of limited government. We argue that Locke’s theory not only permits but requires governments to act to address the climate crisis.
Many previous interpreters of Locke have taken the position that his theory prohibits much in the way of government action to combat climate change. For example, Luc Bovens has argued that efforts to rapidly equalize emissions limits across all countries violate the rights of the industrialized world. He concluded that heavy-emitting economically developed countries must be allowed to temporarily maintain higher levels of greenhouse gas emissions to preserve the property and prosperity their labor and investment have earned. Eric Mack proposed a “self-ownership proviso” that he argues is environmentally friendly but is compatible only with very minimal government regulation of human activity. Edwin Dolan similarly argued that Locke’s theory requires market-based solutions to climate change, not governmental ones. In short, the scope of legitimate government action to combat climate change is questionable on Lockean grounds. Nonetheless, a Lockean justification is available for a government approach to addressing the existential threat of climate change, and it begins with Locke’s proviso that “enough and as good” be left for others (hereafter “EAG”).
Enough and As Good
For Locke’s principle that one leave enough and as good for others to hold, natural resources must be commonly owned prior to initial acquisition by individuals. Locke built his argument from an initial situation of common ownership, and thus both acquisition and its limits are explicitly built on that premise. Humans can take for their own use because “The Earth, and all inferior Creatures be common to all men,” and each may say that, once they have mixed their labor with a part of the commons, they may claim an ownership right “to what that is once joined to, at least where there is enough, and as good, left in common for others (§27).” This grants each individual a use-right to the commons “without which the Common is of no use (§28).”
The limits of acquisition work because of the commons—anything one tries to take beyond what one can use is “more than his share, and belongs to others (§31, emphasis added).” Others are harmed precisely because of their ownership stake in the commons, which allows them to acquire through their labor things that they need for their preservation. Locke tied this directly to the natural law and its requirement that we help to preserve humanity, which includes not wasting resources that could preserve life (§31). Locke’s EAG is therefore built directly from the earth and its status as a commons.
In the absence of common ownership, Locke’s limits on acquisition would lose their force. When I take more than I can use—violating Locke’s “spoilage” proviso—or fail to leave sufficient quality and/or quantity for others, I harm them because they had an ownership stake in what I acquired. In wasting what was also theirs and leaving them with not enough and not as good, I deprive them of these resources and, consequently, I threaten their preservation—violating natural law. Without common ownership, no violation can be claimed. They cannot be said to be worse off than they were before because I have not taken anything that belonged to them. They would be better off if they had acquired before me, but as they did not have an ownership stake in what I took, I would not have violated their rights or made them worse off than they were before I acted.
While earth’s status as a commons is essential to the EAG, Locke’s justification has become less tenable over time. He took his proof of common ownership from the Old Testament account of creation; he repeatedly stated that the Earth is God’s gift, and that acquisition works through God’s rules. God is present at all stages of Locke’s argument, from the Earth as a commons, to the initial acquisition, to the limits on acquisition (§31).
Locke’s argument is deeply rooted in Christianity, but an expressly Christian account fails to provide the broad base for consensus in the secular twenty-first century and in societies marked by religious pluralism. For global problems like climate change, broad-based consensus requires bringing together countries from a host of religious traditions. To bring the EAG out of Locke’s world and into ours, we need a justification for the EAG that will find broad support in today’s political and intellectual milieu. Accordingly, while some existing scholarship argues that secularizing Locke results in the privatization of the commons because of the loss of the divine sanction, we argue for the Earth as a commons within a secularized but still Lockean framework.
In a chapter dedicated to property, Locke explained rivers exist as a commonly held property, and “no body 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 (§33).” The point is well taken, as we can see that one drink—even a “good draught”—does not deprive others nor ruin its usefulness. We can also entertain an alternative, however: imagine that someone, rather than taking a drink, instead dumps poison into the river. In this case, all who would have made use of the river are now injured by it. The available water is no longer “as good” for future water drinkers.
Just as rivers are subject to EAG, so too is the climate commons. Pollution and improper waste disposal make rivers dangerous to drink, reducing the quality of water left for others. Similarly, the climate commons can be readily damaged, or even ruined, at a cost to human health and wellbeing. The pollution of a commons has been known since well before climate change was a common part of political discourse. For example, Beijing and Los Angeles are both notorious for their smog. As a result of human action, emissions, the air quality is damaged, and unhealthy air days have been common in both cities for years. This situation can be understood as a classic tragedy of the commons, further demonstrating the applicability of Locke’s statements regarding rivers. Since the actions of emitters are harmful to others, the natural law’s requirements have been violated.
The Climate as a Commons
While greenhouse gases are generally less directly observable by individuals in their daily lives than smog, they remain a negative externality, one that damages the global climate commons. By raising global temperatures, greenhouse gas emissions imperil numerous common stocks. Rising sea levels due to melting ice caps on a warming planet threaten much of the world’s population, with 30% of the U.S. population and eight of the world’s ten largest cities close enough to the coast to be threatened by flooding. Rising sea levels are thus a threat to both life and property, two of the three things Locke says we create government to secure, and they could reduce the livable surface of the earth if low-lying cities such as Amsterdam, Miami, and New Orleans—which is below sea level—are lost.
It might be suggested that climate change damages property, and therefore a shorter route to addressing climate change would be to simply focus on property damage rather than the question of whether the climate is a commons. If property is destroyed, surely government can act. However, because the effects are indirect, via climate, we cannot ignore the property status of the climate itself. If the climate is not a commons, then each individual action that contributes to climate change is not self-evidently a harm to others. Therefore governments might not be able to limit an individual’s liberty of choice or impose costs on their actions. Instead, governments could only mitigate the effects of climate change after the damage is done rather than addressing the root causes that result in property damage. Our establishment of the global climate as a commons is essential for showing that governments are obliged to act regarding both the causes and effects of climate change.
Locke’s understanding of natural law was that humans are required to preserve themselves and others to ensure the survival, and ideally flourishing, of the human species. He accordingly elaborated limits on acquisition, including the EAG, in the context of foodstuffs. Failure to leave enough and as good harms others by threatening their ability to secure sustenance. Leaving behind less and lower quality food supplies is thus a quintessential violation of natural law that strikes directly at the survival of other humans, and therefore requires rectification. The threat of climate change to fisheries alone threatens nearly a fifth of global animal-protein supplies and a core foodstuff for billions of people. On land, imperiling the crops of farmers the world over threatens food shortages that have the potential to increase famine, decrease survival and quality of life, and increase mortality, especially among the world’s poorest. Global climate change is therefore a fundamental threat to life, liberty, and estate, in which governments have clear authority to act in a Lockean system.
Beyond merely allowing governments to act on climate change, we argue that the natural law and EAG require them to act. For a Lockean government to enforce a positive moral obligation to act may seem controversial at first glance. However, here, we will show that it logically follows from the structure of the natural law and Locke’s understanding of why governments exist. We begin where Locke begins: with the definition and function of natural law in the state of nature.
In chapter two of the Second Treatise, Locke wrote that the law of nature “teaches all mankind” that “no one ought to harm another in his life, health, liberty, or possessions” and that we ought, as much as we can, “to preserve the rest of mankind (§5).” Individuals in the state of nature therefore have a positive obligation to act to preserve others. Of course, in the natural state, the execution of the natural law is in the hands of every individual, and therefore highly uncertain and partial. This point brings us to the next step: the departure from the state of nature.
In leaving the state of nature, Locke tells us that we create governments for the purpose of executing natural law, whose execution is otherwise defective (§§124–126). Government is therefore empowered not simply to prevent violence, just as individuals in the state of nature are not obligated to merely avoid injuring others. Instead, government must act to advance human preservation. Locke states this most explicitly in chapter seven of the Second Treatise, when he writes that the creation of government “authorizes the Society, or which is all one, the Legislative thereof to make laws for him as the publick good of society shall require (§89).” He echoed this idea later in chapter nine, writing that the full apparatus of government is “to be directed to no other end, but the peace, safety, and public good of the people (§131, emphases in original).”
Civil laws must be in accordance with the natural law because “the law of nature stands as an eternal rule to all men, legislators as well as others. The rules that they make for other men’s actions, must, as well as their own and other men’s actions, be conformable to the law of nature (§135).” “The obligations of the law of nature cease not in society”; they are simply clarified by the civil laws, which exist so that “the people may know their duty (§137).” This obligation includes their duties to preserve the lives of others. It would be unfair to expect the individual to be aware of every externality of their actions, especially on a subject as scientifically complex as global climate change. Accordingly, the government will act to deal with the negative externalities of individual choices. The natural law requiring that the government act in response to threats such as global climate change is a result of the EAG and is little more than a core function of all governments.
A possible objection here is that Locke states “government has no other end than the preservation of property (§94),” and that what we propose oversteps this scope. However, Locke does not have a narrow definition of property as simply land and goods; rather property includes “lives, liberties and estates, which I call by the general name, property (§94, emphasis in original).” Two of these types of property—life and estate—are threatened with increasing frequency because of climate change. As noted above, fires, storms, and rising sea levels all threaten to destroy both life and estate. Moreover, the level of property damage (estate damage in Locke’s terms) is rising by the year, with incidents of weather disasters that cause a billion dollars of damage now standing at all-time highs, and the five years with the greatest number of billion-dollar disasters having all occurred since 2011. If the government fails to act on climate change, the destruction of our estates will continue its current rapid increase.
We have not taken a position on what climate policies governments should pursue. Policy formation should be driven by the climate scientists in many fields who have devoted their research to the threatened global ecosystems, the causes and effects of climate change, as well as effective solutions, and can therefore provide evidence-based policy proposals to government actors.
But political theory’s contribution is more than just showing that governments may act without having to worry about overstepping the boundaries of Lockean theory. Even with a moral obligation to act, a government could still overstep other requirements of natural law in attempting to fulfill this one. After all, banning beef, prohibiting air travel, and seizing all private jets would massively decrease greenhouse gas emissions at a stroke, but such policies would be flagrant violations of individual liberty and property rights under any reading of Locke. Less invasive means exist and should be preferred. For instance, a carbon tax would be a reasonable measure tied directly to activities that produce climate-changing emissions. Such a tax would comport with Locke’s acknowledgment that taxation is needed to support government’s protective activities (§140).
As fires burn, oceans rise, and crops are damaged, it is not far-fetched to imagine people in the hardest-hit areas leaving their homes in search of refuge in less hard-hit areas. In fact, this eventuality has been anticipated by leaders of low-lying island nations in the South Pacific, and their plans for migration examined by scholars. Receiving states will not necessarily be overjoyed to welcome these refugees in large numbers, as controversies over the reception of Syrian, Afghan, and other refugees in the United States and the European Union make clear. To what extent are Locke, and the Lockean framework we develop, useful for understanding these refugees’ rights?
People in some countries, like Tuvalu and the Cook Islands, are extremely vulnerable to climate change, but their governments cannot significantly mitigate it, even with the most aggressive policies. The Lockean law of nature would require a right of exit for survival in the face of rising sea levels, making the question of the status of climate refugees especially pressing. Locke deeply understood the utility and, at times, the necessity of such a choice. He lived through the English Civil War and spent five years in exile in the Netherlands after he was accused of conspiring against Charles II in the Rye House Plot of 1683. He only chose to return to England with the overthrow of James II in 1688. A Lockean right of exit in the face of danger has solid textual and historical foundations.
Conclusion
Locke and his philosophy of limited government remain central to American political thought, and to the liberal political tradition more generally, in both academic discourse and public political rhetoric. He has also long been seen as a problematic thinker for constructing an environmental political theory due to his emphasis on individual acquisition and the human mastery of nature. We have sought to go beyond recent arguments that Locke and environmentalism are compatible. We show how Locke’s understanding of natural law and the government’s role in enforcing it to safeguard the survival and welfare of the human species gives Lockean theory the tools necessary to confront an existential threat like global climate change.
More broadly, we argue that government is obligated by the natural law to pursue climate policies. Because it exists solely to enforce the natural law, this is part of its raison d'être. Failure to do so can end the subjects’ political obligation when it becomes “a long train of abuses” that deprives the subjects of their life and property. Climate refugees are an especially salient application of this principle. We suggest the Lockean rationale we have outlined may justify a rebellion against governments who fail to act against climate change. But more practically, we demonstrate that climate refugees are not only justified in migrating to more hospitable areas, but also that receiving states are obligated by the natural law to admit these refugees and aid in their resettlement.
Our close examination of the EAG has significant consequences for political theory. In providing a secular, contractarian basis for treating the earth and its natural resources as a commons, we demonstrate the applicability of the EAG to the problems of modern environmentalism. The Locke we have uncovered would advocate, rather than prohibit, government action to protect a commons that we cannot help but share.
