ENVIRONMENTAL AND ANIMAL ETHICS

Every ethical theory you have met so far asked a version of the same question: what do we owe, and to whom? This chapter presses on the second half. A patient in front of you plainly counts. Does a beagle in a toxicology lab? A laying hen in a cage the size of a sheet of paper? A river? A child who will be born in 2085 into a city that floods because of decisions made this decade? These are not abstractions. They are settled every day by regulators writing exposure limits, by legislators pricing carbon, by hospitals choosing anesthetic gases, and by shoppers standing in front of a refrigerated case. You will meet the arguments that widened the moral circle, the evidence that forced science and law to take animal sentience seriously, the distinctive puzzles that make climate obligations so slippery, and the hard record of where environmental harm actually lands — disproportionately on poor communities and communities of color. Then you will learn the tools practitioners use to decide, and where those tools quietly fail.

Section 1Who Counts? Drawing the Moral Circle

Moral status, and the question behind the question

To have moral status is to be the kind of thing that can be wronged, not merely damaged. Smashing a stranger’s laptop is wrong, but the wrong is done to the owner, not to the laptop. The laptop has no interests of its own. The whole dispute in environmental and animal ethics is whether anything besides human beings is more like the owner than like the laptop — and if so, on what grounds.

Notice that moral status is not the same as moral agency. A moral agent can deliberate, weigh reasons and be held responsible. A moral patient can be wronged but cannot be blamed. Infants, people in advanced dementia and people with profound cognitive disability are moral patients whose status nobody serious disputes. That asymmetry does real argumentative work later, because any criterion that excludes animals by demanding rationality tends to exclude some humans too.

The Western tradition long answered the question narrowly. Aristotle ranked nature as a hierarchy with plants for animals and animals for humans. Aquinas absorbed that ranking into Christian theology. René Descartes went furthest: in the 1630s he described non-human animals as bêtes-machines, complex automata whose cries were the creaking of machinery rather than the expression of felt pain. That view licensed vivisection without anesthesia for two centuries, and it is worth remembering that it was a philosophical claim, not an empirical finding.

Immanuel Kant offered the most influential compromise, and it is the one still doing quiet work in a lot of everyday thinking. In his Lectures on Ethics Kant held that we have no direct duties to animals, because duties are owed to rational beings capable of legislating moral law. But we have indirect duties regarding them: cruelty to a dog coarsens the character and makes cruelty to humans easier. On this view, kicking a dog is wrong because of what it does to you. Many people find that conclusion gets the verdict right and the reason spectacularly wrong. The Kantian philosopher Christine Korsgaard argued in Fellow Creatures (2018) that Kant’s own framework, properly worked out, supports direct duties — because animals, like us, are beings for whom things can be good or bad, and that is what makes anything matter at all.

Sentience and the case for animals

The modern turn begins with Jeremy Bentham. In a footnote to his Introduction to the Principles of Morals and Legislation (1789), written while the French colonies still held slaves, Bentham argued that the decisive question about animals is not whether they can reason or talk, but whether they can suffer. If suffering is the bad thing, the boundary of moral concern is sentience — the capacity for felt experience — and species membership is beside the point.

Peter Singer built the contemporary movement on that foundation. Animal Liberation (1975) argues from the principle of equal consideration of interests: a given amount of suffering counts equally, whoever suffers it. Equal consideration does not mean identical treatment — a pig has no interest in voting — but it does mean that a pig’s interest in avoiding pain cannot be discounted simply because the pig is a pig. Discounting it is what Richard Ryder in 1970 named speciesism. The term is a charge with a precise structure, not an insult: it alleges that species is being used exactly as race and sex have been used, as a morally irrelevant marker that conveniently favors the group doing the judging.

The sharpest supporting argument is the argument from marginal cases. Name the capacity that supposedly grounds human moral status — abstract reasoning, language, autonomy, reciprocity. Some humans lack it: a newborn, a person in the late stages of Alzheimer disease. We do not conclude that those humans may be used in painful experiments or eaten. So either the capacity is not what grounds status, or we are applying it inconsistently. Carl Cohen replied in the New England Journal of Medicine in 1986 that moral status attaches to the kind of being one is, so that a human who lacks rationality still belongs to a rational kind. Critics answer that appealing to kind membership rather than actual capacities is precisely what the speciesism charge alleges.

Tom Regan took a rights-based rather than utilitarian route. In The Case for Animal Rights (1983) he argued that any being that is a subject-of-a-life — that has beliefs, desires, memory, a sense of the future, and a welfare that matters to it — has inherent value that cannot be traded away for aggregate benefit. Regan was explicit that this rules out animal experimentation even when the research would save many lives, which is where his view and Singer’s come apart. Singer’s utilitarianism can in principle license a painful experiment with enormous benefit; Regan’s rights view cannot.

Science and law have moved toward the sentientist position, though unevenly. The Cambridge Declaration on Consciousness, signed in July 2012 by a group of neuroscientists, stated that the neural substrates of conscious experience are not unique to humans and are present in mammals, birds and octopuses. The New York Declaration on Animal Consciousness (April 2024) went further, asserting strong scientific support for consciousness in mammals and birds and a realistic possibility of it in reptiles, fish, cephalopods and even some insects. In law, Article 13 of the Treaty on the Functioning of the European Union, in force since December 2009, obliges the Union and its member states to pay full regard to animal welfare when framing key policies, because animals are sentient beings. The United Kingdom’s Animal Welfare (Sentience) Act 2022 went further still, extending legal recognition of sentience to cephalopod molluscs and decapod crustaceans after a systematic review led by Jonathan Birch at the London School of Economics found substantial evidence of pain in octopuses, crabs and lobsters.

Beyond sentience: living things, land and systems

Sentientism has an awkward implication for environmentalism: it cannot directly value a redwood, a wetland, or a species. Trees do not suffer. A species has no nervous system. Yet most people think destroying the last population of a beetle is a genuine wrong and not merely an aesthetic loss. Two families of theory try to capture that.

Biocentrism extends status to all living things. Paul Taylor’s Respect for Nature (1986) argues that every organism is a teleological center of life — it has a good of its own, a direction of flourishing, whether or not it is aware of it. Watering a plant benefits it in a non-metaphorical sense. Taylor’s version is famously egalitarian, denying that human interests automatically outrank a fern’s, which most readers find impossible to live by. Less radical biocentrists allow that the richness of a being’s good affects how much weight it gets.

Ecocentrism shifts the unit of concern from individuals to wholes: populations, species, ecosystems, the land itself. Aldo Leopold’s A Sand County Almanac, published in 1949 shortly after his death, proposed a land ethic in which the community deserving of moral consideration includes soils, waters, plants and animals, and in which rightness is measured by whether an action preserves the integrity, stability and beauty of that biotic community. Arne Naess extended the theme in 1973 into deep ecology, contrasting a shallow environmentalism concerned with pollution and resources for wealthy humans with a deep view that grants intrinsic value to non-human life and calls for a smaller human footprint.

Holism has a real cost, and honest ecocentrists concede it. If the good of the ecosystem is what counts, then culling deer, poisoning invasive rats on an island, or even — on the most aggressive reading — reducing human numbers becomes permissible or required. Regan called this environmental fascism, arguing that individual lives cannot be sacrificed to systemic tidiness. J. Baird Callicott, Leopold’s most careful defender, has spent decades arguing that the land ethic layers onto rather than replaces our duties to individuals. Whether holistic entities can genuinely have interests remains one of the live, unsettled disputes in the field, not a question with a settled classroom answer.

A fourth tradition reframes the whole map. Ecofeminists such as Karen Warren and Val Plumwood argue that the domination of nature and the domination of women share a conceptual structure: a set of dualisms — reason over emotion, culture over nature, mind over body, male over female — in which one side is defined as superior and the other as available for use. Plumwood wrote from unusual experience. In February 1985, while paddling in Kakadu National Park in Australia, she was seized by a saltwater crocodile and survived three death rolls. She described the event as shattering the illusion of being outside the food chain, and it shaped her insistence in Feminism and the Mastery of Nature (1993) that humans are both ecological beings and moral ones.

Section 2Animals in Laboratories, Farms and Fisheries

The laboratory: the Three Rs and the gaps in the law

In 1959 the zoologist William Russell and the microbiologist Rex Burch published The Principles of Humane Experimental Technique and gave the field its organizing framework: the Three Rs. Replacement means substituting non-animal methods wherever possible. Reduction means using the fewest animals consistent with a statistically meaningful result. Refinement means minimizing pain and distress in the animals still used. The framework is now written into law on both sides of the Atlantic, and it is genuinely useful. It is also, by design, a framework for doing animal research better rather than for asking whether a given experiment should happen at all.

The United States Animal Welfare Act, passed in 1966 after Life magazine ran a photo essay on stolen dogs sold to laboratories, sets housing, veterinary care and record-keeping standards. Two scandals forced it wider. In 1981 Alex Pacheco documented conditions in Edward Taub’s deafferentation experiments on macaques at the Institute for Behavioral Research in Silver Spring, Maryland. In 1984 the Animal Liberation Front took videotapes from the University of Pennsylvania Head Injury Clinic showing baboons subjected to whiplash injury while researchers joked on camera, and the laboratory was suspended in July 1985. Congress responded with the Improved Standards for Laboratory Animals Act of 1985, which created the Institutional Animal Care and Use Committee — a local review board, structurally similar to a human-subjects IRB, that must include a veterinarian and at least one member unaffiliated with the institution.

European law goes further on paper. Directive 2010/63/EU requires a formal harm-benefit analysis for every project, classifies procedures by severity, and prohibits procedures involving severe pain that is likely to be long-lasting and cannot be alleviated. The European Union also banned animal testing for cosmetics ingredients in 2009 and the marketing of animal-tested cosmetics in 2013, a prohibition that pushed the global cosmetics industry toward validated alternatives faster than decades of argument had. The Draize eye irritation test, introduced by the FDA scientist John Draize in 1944 and long the emblem of the movement, has largely been displaced in that sector by reconstructed human cornea models and computational screens.

Momentum now sits with new approach methodologies: organ-on-a-chip systems, human induced pluripotent stem cell models, high-throughput in vitro screens, and computational structure-activity modeling. In December 2022 the United States enacted the FDA Modernization Act 2.0, which removed the statutory requirement that a drug be tested in animals before entering human trials and explicitly permits validated alternatives. Be precise about what that law did and did not do: it permits, it does not prohibit, and animals remain the default across most preclinical pipelines. The scientific case for change is not only ethical. Roughly nine out of ten drugs that clear animal testing and enter human trials still fail, most often for lack of efficacy or for unforeseen toxicity, which is a poor record for a predictive model.

The farm: scale, confinement and the welfare argument

Scale is the first thing to get straight, because intuitions calibrated on a family farm are useless here. Roughly 80 billion land animals are slaughtered for food worldwide each year, the overwhelming majority of them chickens; estimates for fish and other aquatic animals run into the hundreds of billions or higher and are far less certain. In the United States alone the figure approaches 10 billion land animals annually, more than nine in ten of them broiler chickens. No other human practice touches sentient creatures on anything close to this order of magnitude.

Confinement is the second. A conventional battery cage gives a laying hen less usable floor area than a sheet of letter paper and no room to spread her wings, nest, perch or dust-bathe. A gestation crate holds a breeding sow in a stall roughly her own body length for most of a four-month pregnancy, so that she cannot turn around. The European Union banned conventional battery cages from January 2012 under Directive 1999/74/EC and restricted gestation crates to the first four weeks after service from 2013. In the United States change has come state by state through ballot measures: California’s Proposition 2 in 2008, Massachusetts Question 3 in 2016, and California’s Proposition 12 in 2018, which uniquely regulated the sale of pork, veal and eggs from confined animals regardless of where they were raised. Pork producers challenged Proposition 12 as an unconstitutional burden on interstate commerce and lost: the Supreme Court upheld it in National Pork Producers Council v. Ross, decided in May 2023.

Genetics has done as much damage as housing. The modern broiler chicken reaches a slaughter weight near 2.5 kilograms in about six weeks; in 1957 the same species took roughly three months to reach a market weight little more than half that. Comparative work by Martin Zuidhof and colleagues in 2014, raising 1957, 1978 and 2005 strains under identical conditions, found the modern bird grew more than four times as large by day 56. That selection carries predictable costs: lameness and skeletal disease, because leg bone cannot keep pace with breast muscle; ascites from cardiovascular strain; and contact dermatitis in birds that sit because standing hurts. The animal-science reformer Temple Grandin, whose curved chutes and center-track restrainers became industry standard and whose audits reshaped slaughter practice for major buyers from 1999 onward, has been blunt that you cannot audit your way out of a genetics problem.

Two further consequences bear directly on health care. First, roughly two-thirds of medically important antibiotics sold in the United States go to food animals; the FDA’s Veterinary Feed Directive, effective January 2017, ended their use purely for growth promotion, but the selection pressure that remains is an argument about human medicine, not only animal welfare. Second, dense confinement of genetically uniform animals in close contact with people is an efficient incubator for zoonoses — the Nipah virus outbreak on Malaysian pig farms in 1998 and 1999 and the continuing evolution of highly pathogenic avian influenza are the standard examples. The Humane Methods of Slaughter Act of 1958, strengthened in 1978, requires that livestock be rendered insensible before shackling, but the USDA has long interpreted it as not covering poultry — which is to say, as not covering the great majority of animals killed.

Welfare, abolition, and what a defensible position looks like

Within animal ethics the deepest split is not between advocates and industry but between welfarists and abolitionists. Welfarists, following Singer’s consequentialism, hold that the wrong lies in suffering, so reforms that remove cages, improve stunning or reduce numbers are genuine moral progress. Abolitionists, following Gary Francione, hold that the wrong lies in property status itself: while animals are legally things, welfare standards will settle wherever they are cheap, and by reassuring consumers those standards may prolong the institution they soften. This is a real disagreement about both strategy and principle, and it has not been settled by argument.

A third position, sometimes called conscientious omnivorism, accepts that killing animals for food can be permissible if they live good lives and die without terror, and aims its energy at how animals are raised rather than whether they are eaten. Critics point out how little of the supply chain that position actually reaches: “natural” and “farm fresh” are unregulated marketing, “cage-free” permits crowded barn housing, and audited certification schemes differ enormously from one another. Defenders reply that a movement demanding total abstention loses the many people who will change most of their diet but not all of it, and that reductions at population scale matter more than purity at individual scale.

Technology may reroute the argument. Singapore approved the sale of cultured chicken in December 2020, the first country to do so; in the United States the FDA issued no-questions letters to UPSIDE Foods in November 2022 and GOOD Meat in March 2023, and the USDA granted label approvals in June 2023. Whether cultivated meat can scale to price parity is a genuinely open engineering and economic question, and several states, Florida among them in 2024, moved to ban its sale outright — a reminder that technological solutions to ethical problems arrive inside politics. Plant-based substitution has meanwhile grown large enough to move agricultural markets, and its environmental case is independent of the welfare case: animal products supply roughly 18 percent of global calories while accounting for well over half of food-system greenhouse emissions and occupying the large majority of agricultural land.

Section 3Climate Change: Harm Across Distance and Time

What we know, and how we came to know it

The physics is old and unglamorous. In 1856 the American scientist Eunice Newton Foote reported that a cylinder of carbon dioxide warmed more in sunlight than one of ordinary air. John Tyndall measured the infrared absorption of atmospheric gases in 1859. In 1896 the Swedish chemist Svante Arrhenius calculated by hand what doubling atmospheric carbon dioxide would do to surface temperature and got 5 to 6 degrees Celsius — higher than the modern best estimate near 3, but the right order of magnitude for arithmetic done with pen and paper. None of this was controversial when it was done; it became controversial only when its implications acquired a price tag.

The measurement that made abstraction concrete began in March 1958, when Charles David Keeling started continuous sampling at the Mauna Loa Observatory in Hawaii. His first readings were near 315 parts per million. The Keeling curve has risen every year since, sawtoothing with the northern hemisphere growing season, and has now passed 420 parts per million against a pre-industrial baseline near 280. The Intergovernmental Panel on Climate Change concluded in its Sixth Assessment cycle, completed with the Synthesis Report in March 2023, that human influence has unequivocally warmed the planet, by about 1.1 degrees Celsius in the 2011 to 2020 decade relative to 1850 to 1900. Copernicus and the World Meteorological Organization reported 2024 as the first calendar year to average more than 1.5 degrees above that baseline — not yet a breach of the Paris goal, which is defined over decades, but a marker nobody expected this soon.

For clinicians the consequences are not projections but caseload. The European heat wave of August 2003 was associated with roughly 70,000 excess deaths, concentrated in elderly people living alone in cities. Heat-related mortality among people over 65 has risen sharply over the past three decades. Warming extends the range and season of Aedes mosquitoes and of Ixodes ticks, alters pollen seasons and asthma burden, degrades air quality through ozone formation and wildfire smoke, and drives displacement, which is itself a health exposure. Attribution science has matured enough that specific events can now be quantified: teams routinely estimate how much more likely a given heat wave or rainfall extreme was made by warming already in the system.

Who owes what, and on what principle

The 1992 UN Framework Convention on Climate Change committed parties to act on the basis of common but differentiated responsibilities and respective capabilities — language that acknowledges a shared problem with unequal authorship and unequal means. Everything contentious about climate diplomacy is contained in how you cash that phrase out, and the arithmetic you choose changes the answer entirely. By cumulative fossil carbon dioxide emitted since the industrial revolution, the United States is responsible for roughly a quarter of the total and the European Union for something near a sixth. By current annual emissions, China is the largest emitter at roughly 30 percent of the global total. By emissions per person, the ranking flips again: an average American emits several times what an average Indian does.

The Paris Agreement, adopted on 12 December 2015 and in force from November 2016, abandoned the attempt to assign binding shares. It set a collective goal — holding warming well below 2 degrees while pursuing efforts to limit it to 1.5 — and left each country to declare its own nationally determined contribution, subject to a five-year ratchet and transparency review. Critics call this an agreement to be graded on effort. Defenders point out that the binding-target approach produced the Kyoto Protocol, which the United States never ratified and Canada left.

Two more recent developments matter. At COP27 in Sharm el-Sheikh in November 2022, parties agreed in principle to a loss and damage fund for countries suffering climate impacts they did little to cause; it was operationalized at COP28 in Dubai the following year with initial pledges of a few hundred million dollars — a sum orders of magnitude below credible estimates of need, but a change in the moral framing from charity to responsibility. And in 2025 the International Court of Justice issued an advisory opinion holding that states’ climate obligations arise from existing treaty and customary international law, and that breaching them can constitute an internationally wrongful act. Advisory opinions do not enforce themselves, but they change what national courts and negotiators can cite.

It is worth holding onto one clear success. The Montreal Protocol, agreed in 1987 to phase out chlorofluorocarbons after Mario Molina and Sherwood Rowland identified the ozone-destruction mechanism, achieved universal ratification, worked, and is projected to return the ozone layer to 1980 conditions around the middle of this century. Its 2016 Kigali Amendment extended it to hydrofluorocarbons, which are potent greenhouse gases. The differences from climate are instructive — fewer substances, fewer producers, cheap substitutes — but the case refutes the claim that collective action on an atmospheric commons is impossible.

Four puzzles that make climate ethics genuinely hard

The first is the non-identity problem, set out by Derek Parfit in Reasons and Persons (1984). Large policy choices change who is conceived: different jobs, different migrations, different meetings, different children. A person born in 2085 into a badly damaged world would not have existed had we chosen differently. So it seems we have not made that person worse off than they would otherwise have been, and if harm requires making someone worse off, we have not harmed them. Almost nobody accepts the conclusion, and responses vary: some adopt impersonal principles under which a worse world is worse full stop, some argue that being brought into a life below a decent threshold is itself a harm, some deny that harm requires comparison to a person’s own alternative. The puzzle is not a loophole. It is a demonstration that our ordinary harm concept was built for identifiable victims and breaks under policy scale.

The second is the discount rate. To compare costs today with benefits in 2120, economists discount future values. The choice is enormously consequential: at a 5 percent annual rate, a million dollars of damage a century out is worth under eight thousand today; at 1.4 percent it is worth roughly a quarter of a million. The Stern Review, published in October 2006 for the UK Treasury, used a low rate on the ethical ground that a person’s wellbeing should not count less simply because they are born later, and concluded that strong immediate action pays. William Nordhaus, who won the Nobel in economics in 2018, used a higher market-derived rate and concluded that a more gradual ramp was optimal. They were not disagreeing about physics.

The third is the structure of a commons. Garrett Hardin’s 1968 essay in Science described herders each rationally adding one more animal to shared pasture until it collapses, and the image has dominated policy talk ever since. Two corrections are required. The essay also argued for coercive limits on reproduction, and Hardin’s wider writing ran to openly eugenic and anti-immigrant positions — context rarely supplied when the piece is assigned. More importantly, Elinor Ostrom’s Governing the Commons (1990), which brought her the Nobel in economics in 2009, documented Swiss alpine pastures, Japanese village forests and Spanish irrigation systems that users governed sustainably for centuries. Her design principles — clear boundaries, participatory rule-making, monitoring by users, graduated sanctions, accessible conflict resolution, nested governance — describe what makes shared resources work. The atmosphere lacks most of them, which is diagnostic rather than fatalistic.

The fourth is the problem of the individual. Walter Sinnott-Armstrong argued in 2005 that a single unnecessary Sunday drive causes no detectable harm and so is not itself wrong, though we do have strong obligations to press governments to act. John Broome replies in Climate Matters (2012) that each of us does emit, that emissions do harm, and that a duty of justice not to harm others is not waived by the smallness of one’s share. Shelly Kagan and others argue that even imperceptible contributions matter in expectation, because thresholds exist somewhere and each act carries some probability of triggering one. Courts, meanwhile, have moved: the Dutch Supreme Court upheld the Urgenda ruling in December 2019 ordering a 25 percent cut; the German Federal Constitutional Court held in March 2021 in Neubauer that postponing cuts unconstitutionally burdened the freedom of the young; a Montana court ruled for youth plaintiffs in Held v. Montana in August 2023, affirmed by that state’s supreme court in December 2024; and in April 2024 the European Court of Human Rights, in a case brought by a group of older Swiss women with average age in their seventies who argued heat waves endangered them, found for the first time that inadequate climate policy violated the right to private and family life.

Section 4Environmental Justice: Where the Harm Lands

A movement born beside a landfill

In 1978 a trucking contractor working for the Ward Transformer Company sprayed roughly 30,000 gallons of oil laced with polychlorinated biphenyls along some 240 miles of North Carolina roadside to avoid disposal costs. The state decided to bury the contaminated soil in a new landfill at Afton, in Warren County — the county with the highest proportion of Black residents in the state, and among its poorest. In September 1982 residents lay down in the road in front of the dump trucks. More than 500 people were arrested over six weeks. They did not stop the landfill, but they created a vocabulary.

Evidence followed the protest. A 1983 General Accounting Office study of hazardous waste landfills in eight southeastern states found three of the four were in communities that were majority Black. In 1987 the United Church of Christ Commission for Racial Justice, under Benjamin Chavis, published Toxic Wastes and Race in the United States, the first national statistical study of the question; it reported that race was the strongest single predictor of where commercial hazardous waste facilities were sited, stronger than income. A twenty-year follow-up in 2007 found the disparities had not narrowed. Robert Bullard, who had begun mapping Houston’s waste sites for a 1979 lawsuit brought by his wife, published Dumping in Dixie in 1990 and gave the field its founding sociology. In February 1994 President Clinton signed Executive Order 12898, directing federal agencies to identify and address disproportionately high environmental and health effects on minority and low-income populations.

Three distinct claims travel under the single label, and separating them sharpens any analysis. Distributive justice asks how burdens and benefits are allocated: who breathes the emissions, who uses the product. Procedural justice asks who was in the room: whether hearings were held at times working people could attend, in languages they read, with technical assistance to interpret a permit application. Recognition justice asks whose knowledge and whose way of life is treated as legitimate at all — a question that dominates disputes over Indigenous land, as at Standing Rock in 2016, where the Dakota Access Pipeline was rerouted away from Bismarck, a majority-white city, to a crossing immediately upstream of the Standing Rock Sioux Tribe’s water intake.

Three case files

Bhopal, 2 to 3 December 1984. At the Union Carbide India Limited pesticide plant, water entered a storage tank holding roughly 40 tonnes of methyl isocyanate. The runaway exothermic reaction vented a heavier-than-air toxic cloud over sleeping shantytowns built up against the plant wall. The refrigeration unit that should have kept the tank cold had been shut down to save money; the flare tower and scrubber were inadequate or offline; the alarm was of the same type used for routine drills. The official confirmed toll is about 3,800; credible estimates of deaths over the following weeks and years run to 15,000 or more, with hundreds of thousands injured. Union Carbide settled with the Indian government in 1989 for 470 million dollars — on average a few hundred dollars per claimant. The chief executive, Warren Anderson, was arrested and released on the day he arrived in India in 1984, returned to the United States, and was never tried. The site was never fully remediated and groundwater contamination persists.

Flint, Michigan, 2014 to 2016. On 25 April 2014, a city under state-appointed emergency management switched its water source to the Flint River to save money. Michigan’s Department of Environmental Quality did not require corrosion control treatment, so the corrosive river water stripped protective scale from aging lead service lines. Residents complained for eighteen months about color, smell and rashes and were told the water met standards. Marc Edwards of Virginia Tech independently sampled homes in August 2015 and found lead at levels that meet the definition of hazardous waste in some samples. On 24 September 2015 Dr. Mona Hanna-Attisha, a pediatrician at Hurley Medical Center, presented blood lead data showing the proportion of Flint children with elevated levels had roughly doubled citywide and tripled in the highest-exposure neighborhoods. A concurrent Legionnaires disease outbreak killed at least twelve people. Flint’s population was about 54 percent Black with around 40 percent living in poverty. The Michigan Civil Rights Commission concluded in February 2017 that systemic racism was a root cause. Criminal prosecutions of senior officials collapsed after the Michigan Supreme Court invalidated the one-judge grand jury procedure used to charge them.

The Louisiana chemical corridor. Along the 85 miles of the Mississippi River between Baton Rouge and New Orleans sit roughly 200 petrochemical facilities, many on former plantation land where the descendants of the enslaved still live. In St. John the Baptist Parish, the National Air Toxics Assessment the EPA released in 2015 identified census tracts with the highest estimated cancer risk from air toxics in the country, driven by chloroprene emitted by a neoprene plant. The EPA finalized a rule in April 2024 tightening chloroprene and ethylene oxide controls; an earlier civil rights investigation was dropped in 2023 after the state attorney general sued. The corridor illustrates the pattern precisely: the products are national, the tax base is modest, and the exposure is measured in the length of a driveway.

The clinical face of environmental injustice

Air pollution is not a background nuisance; it is one of the largest risk factors for death on earth. The Health Effects Institute’s State of Global Air analysis attributed roughly 8.1 million deaths worldwide in 2021 to air pollution, ranking it second among all risk factors for death worldwide, behind high blood pressure, and second among risk factors for death in children under five, behind malnutrition. Fine particulate matter under 2.5 micrometers penetrates to the alveoli and enters the bloodstream; the Harvard Six Cities Study published in the New England Journal of Medicine in 1993 established the mortality gradient across American cities and underpins modern standards. Within any city the gradient repeats along highways, ports and rail yards, which are not randomly located.

Lead is the cleanest illustration of exposure without a threshold. There is no known safe blood lead level in children; the CDC lowered its reference value to 3.5 micrograms per deciliter in 2021 precisely because the old cutoff implied a safety that does not exist. Effects on IQ, attention and behavior are permanent, they are strongest at the lowest concentrations, and they map onto old housing stock and old service lines, which map onto historic redlining. Heat does the same thing spatially: work by Jeremy Hoffman and colleagues in 2020 found that formerly redlined neighborhoods run several degrees hotter than affluent parts of the same city on a summer afternoon, because they have less canopy and more pavement. A heat wave is therefore not one exposure but many, sorted by the map drawn in the 1930s.

This is where an environmental chapter becomes a clinical one. If you work in a clinic, environmental exposure is part of the history and usually goes unasked: occupation and second jobs, distance from a highway or facility, housing age, well versus municipal water, heat and air conditioning at home, food and pharmacy access. Documenting exposure in the chart is not paperwork; aggregated, it is the evidence base that makes a community’s claim legible to regulators. The precautionary principle — articulated as Principle 15 of the 1992 Rio Declaration and sharpened in the 1998 Wingspread Statement to say that when an activity threatens harm, precautionary measures should be taken even if some cause-and-effect relationships are not fully established scientifically — is the formal statement of a stance clinicians already take when they act on a worrying sign before the confirmatory test returns. Its critics are right that a strong reading can paralyze, since every intervention carries some risk; the useful version shifts the burden of proof toward the party creating the exposure rather than forbidding action.

One legal movement deserves mention because students encounter it and it is easy to caricature. Rights of nature statutes give ecosystems standing to be represented in court, an idea Christopher Stone proposed in his 1972 article “Should Trees Have Standing?” and that Justice William O. Douglas took up in dissent that same year. Ecuador wrote rights of nature into its 2008 constitution, and its Constitutional Court applied them in 2021 to block mining in the Los Cedros cloud forest. New Zealand’s Te Awa Tupua Act 2017 recognized the Whanganui River as a legal person with two appointed guardians, giving effect to a Māori understanding that the river and the people are indivisible. Spain granted legal personhood to the Mar Menor lagoon in 2022 after a citizens’ initiative followed mass fish die-offs. Whether these instruments change outcomes or mainly change who may sue is still being worked out, but they are a serious answer to a real problem: ecosystems previously had no one whose injury the law would count.

Section 5From Values to Decisions: Tools, Trade-offs and Practice

The tools regulators actually use, and where each fails

Cost-benefit analysis converts consequences into money so that they can be compared. Since Executive Order 12291 in 1981 it has been mandatory for major United States regulations, which means that in practice a great deal of environmental ethics happens inside a spreadsheet. Two numbers carry most of the weight. The social cost of carbon estimates the damage done by emitting one additional tonne of carbon dioxide; the United States used an interim figure near 51 dollars per tonne from 2021, while the EPA’s 2023 update, using a lower near-term discount rate and updated damage functions, put it closer to 190 dollars. The value of a statistical life converts small mortality risks into money using observed wage premiums for dangerous work; federal agencies use figures in the range of 11 to 13 million dollars. Neither number prices a person. Both price a change in risk across a population, which is a different thing and is routinely misreported.

Cost-benefit analysis has three characteristic failures. It handles distribution badly, because a benefit of a hundred dollars counts the same whether it goes to a hedge fund or a household on dialysis. It handles the unpriced badly: after the Exxon Valdez ran aground in Prince William Sound on 24 March 1989 and spilled about 11 million gallons, valuing the loss of a coastline nobody visits required contingent valuation — asking people what they would pay — and the NOAA panel chaired by Kenneth Arrow and Robert Solow in 1993 concluded such surveys can be informative but are easily distorted by how the question is framed. And it handles catastrophic tails badly, because expected-value reasoning is least reliable exactly where the outcome is irreversible.

That last gap is what the precautionary principle and the planetary boundaries framework try to fill. Johan Rockström and colleagues proposed in 2009 that nine Earth-system processes have safe operating ranges beyond which nonlinear change becomes likely; the 2023 update led by Katherine Richardson assessed six of the nine as already transgressed, including climate change, biosphere integrity, land-system change, freshwater change, biogeochemical flows of nitrogen and phosphorus, and novel entities such as synthetic chemicals and plastics. The framework is contested at the level of exact thresholds and is best read as a claim about the shape of risk rather than a set of precise dials. Its ethical contribution is real: it reintroduces the idea of a limit into a discourse otherwise built entirely on trade-offs.

Life-cycle assessment is the most useful tool for everyday institutional decisions and the most frequently misused. It tallies energy, water, emissions and waste across a product’s whole existence, from raw material to disposal, and it regularly overturns intuitions. A cotton tote bag must be reused dozens or hundreds of times before it beats a thin plastic bag on climate, because growing and processing cotton is resource intensive. Whether a reusable surgical gown or laryngoscope blade beats a disposable one depends heavily on how the laundering or reprocessing energy is generated. That context-dependence is the point: LCA gives you an answer for a specified system, not a universal verdict, and any claim that skips the boundary conditions should be treated with suspicion.

The individual, the institution and the citizen

Personal action gets more attention than it deserves and less credit than it is owed, mostly because people rank actions badly. Seth Wynes and Kimberly Nicholas showed in 2017 that the measures most often recommended in textbooks and government guides — recycling, changing light bulbs, hang-drying laundry — are among the least effective, while living without a car, avoiding a long-haul flight and shifting to a plant-based diet are roughly an order of magnitude larger. Joseph Poore and Thomas Nemecek’s 2018 synthesis in Science, covering nearly 40,000 farms, found food production responsible for about a quarter of global greenhouse emissions and calculated that dropping animal products would cut food-related emissions by roughly half and food-related land use by about three-quarters. That is a genuine lever. It is still not the largest one available to most people, which is their vote, their union, their professional association and their employer.

It is worth being honest about why the individual frame is so heavily promoted. The concept of the personal carbon footprint was popularized by an advertising campaign that BP launched in the early 2000s, complete with a footprint calculator. That does not make the concept useless — measurement is how you find leverage — but it does explain why an industry might prefer a conversation about your commute to one about its extraction plans. The same logic produces greenwashing, a term coined by Jay Westerveld in 1986 after noticing that a hotel’s plea to reuse towels for the reef coexisted with unchecked expansion. The definitive case remains Volkswagen: on 18 September 2015 the EPA issued a notice of violation revealing defeat-device software that detected emissions testing and switched to a clean mode, while on the road the vehicles emitted nitrogen oxides at many multiples of the legal limit. About 11 million vehicles worldwide were affected, costs exceeded 30 billion dollars, the chief executive resigned, and an engineer served prison time. The marketing had been built around clean diesel.

Where does that leave a working adult who cannot personally decarbonize a grid? Three answers are defensible together. First, integrity has value independent of effect: acting consistently with what you believe is part of being a certain kind of person, which is the virtue ethicist’s contribution to a debate otherwise dominated by consequences. Second, individual action is rarely purely individual, because norms are contagious and visible choices change what others treat as normal — the diffusion of rooftop solar clusters street by street for exactly this reason. Third, the highest-leverage action for most people is exercised as a member of something: a licensing board that adopts a standard, a hospital that changes its purchasing contract, an electorate that prices carbon. Judging your ethics by your shopping alone is a category error in both directions — it overstates your guilt and understates your power.

Your own sector: the ethics of a lower-carbon clinic

Health care is not a bystander. Health Care Without Harm estimated in 2019 that the global health sector accounts for about 4.4 percent of net global emissions, which would rank it among the largest emitters if it were a country. Analyses by Matthew Eckelman and Jodi Sherman put United States health care at roughly 8.5 percent of national emissions, the highest share of any national health system. There is an obvious ethical tension in a profession organized around primum non nocere generating pollution that measurably harms health, and the profession has begun to say so: in October 2020 NHS England became the first national health system to commit to net zero, targeting its directly controlled emissions by 2040 and its whole supply-chain footprint by 2045.

The leverage points are not the ones people expect, which is why this is a useful test of everything in this chapter. Inhaled anesthetics are potent greenhouse gases with wildly different potencies: desflurane has a global warming potential roughly twenty times that of sevoflurane over a century, and nitrous oxide is both a greenhouse gas and ozone-depleting, with much of a hospital’s piped supply lost to leaks before it reaches a patient. NHS Scotland stopped using desflurane in 2023 and NHS England moved to decommission it, with no evidence of harm to patients, because equally good alternatives exist. Metered-dose inhalers use hydrofluorocarbon propellants; a single salbutamol canister can carry a footprint comparable to driving a small car a hundred miles or more, while a dry powder inhaler is a small fraction of that. Inhalers alone account for roughly 3 percent of the NHS carbon footprint. Neither switch is automatic — some patients cannot generate the inspiratory flow a dry powder device needs, and pressing a switch on a poorly controlled asthmatic is bad medicine — but the default matters at scale.

The largest lever of all is less visible: avoiding care that should not happen. Every unnecessary CT scan, duplicated laboratory panel, low-value screening test and avoidable readmission carries a full environmental footprint of energy, single-use plastic, reagents, transport and staff travel, on top of its financial cost and its risk to the patient. Estimates of wasteful spending in United States health care commonly run to a quarter of the total. A clinician who practices carefully, follows deprescribing evidence, and declines to order the reflexive extra test is doing environmental work that no recycling program can match. This is a satisfying convergence rather than a trade-off: the environmentally best choice, the fiscally best choice and the clinically best choice point the same way more often than the framing of “green versus safe” suggests.

None of this licenses compromising infection control. Single-use devices exist for good reasons and the answer to a plastic problem is not a sepsis problem. What the evidence supports is more specific: correct waste segregation, because material sent down the regulated medical waste stream is incinerated at many times the cost and carbon of ordinary waste and studies repeatedly find most of it was misclassified; reusable textiles and instruments where life-cycle assessment supports them in your local energy mix; procedure-pack redesign to stop opening items that are routinely discarded unused; and telehealth where it is clinically equivalent, since avoided patient travel is often the single largest component of an ambulatory visit’s footprint.

Words worth knowing