The Natural History of the Present, Chapter 13

Chapter 13: The Problem of Economics

It is hard to overestimate the value of natural resources (timber, minerals, fertile farmland) in the development of high civilizations. Abundant resources (natural; or expanded by human ingenuity through technical innovations like metal smelting or irrigation) supported the high human populations. In general, agriculturally based civilisations, which constituted most of the world until 1900, depend on the advantages and resources of their landscapes for their maintenance and growth, while modern economies depend on the application of capital to new products or new markets. (One could argue that the growth of modern trading cities like Singapore and Hong Kong show that a land base is irrelevant to development.) Converting natural resources to human use, that is, to capital (commodifying them) reduces the ecosystem services provided by the landscape. Very generally, such services include the following: regulating climate; maintaining the hydrological cycle, including the rate of rainfall, its distribution throughout the year, and the level of streamflow; filtering out dusts and gases from air and silts from water and turning the nutrients in air and water into biomass; maintaining the gaseous composition of the atmosphere; regulating daily temperatures and windspeeds; forming and maintaining soils; storing and cycling essential nutrients such as calcium, nitrogen, sulfur, carbon; immobilizing or detoxifying pollutants; pollinating crop plants; maintaining large landscapes as functioning wholes. Ecosystem services come down to things like the work of forests in preventing floods; and to the work of bacteria in breaking up the bits of lettuce that go down the drain. The conversion of natural landscapes with their free ecosystem services to man-made landscapes in which those services are eliminated or reduced is a condition of development. During the process of natural succession the physical environment is modified by the biotic community until a more or less stable system is reached. Such a system (a redwood forest, an oakwood, a prairie) reaches its maximum possible biomass partly by exerting substantial biotic control over its environment. So-called primary ecosystems have numerous symbiotic connections among their inhabitants, with many predator-prey relationships (which help maintain population stability), and recycle each molecule of nutrients and water many times. By absorbing and transforming much of what flows through them, such systems provide ecosystem services. Such systems conflict with the human goal of maximizing yield from the soil, a function of younger, more leaky ecosystems (such as tree plantations and wheat fields). Worldwide, about 15% of the land surface not covered by ice has been entirely remade by humans into fields of crops, housing developments, industrial estates and transportation corridors; about 55% of the ice-free landscape has been changed by direct human action, including such uses as grazing and logging. Humans appropriate 30-40% of net primary productivity on land (net growth of land plants); compared to 5% in 1860. (People and their animals directly consume about 4% of this; the rest is recycled or wasted.) We use maybe 35% of the productivity of the oceans; and over half of all rainfall. (Approximately 90% of this is for irrigation.) Fallout of metals, hydrocarbons, and oxides of sulfur and nitrogen affect the whole planet; as do the anthropogenic gases that affect the ozone layer and the global climate. The conversion of natural resources to commodities and the resulting destruction of the natural world has made the modern world possible. Development makes landscapes and their resources saleable; thus landscapes produce income. In the case of the United States, the debt incurred from fighting the Revolution, and for purchasing the present-day Middle West from France (the Louisiana Purchase), was paid off through sales of public land. American railroad companies were granted 10% of the land area of the continental United States in return for the construction of the transcontinental railroads.

Human development of land degrades it by breaking down its nutrient recycling abilities. An ecosystem is defined by its boundaries; a great deal more nutrient exchange occurs within these boundaries than occurs through them. Leakage of nutrients to the great enveloping fluids of air and water is minimized. Climax or primary ecosystems may support great amounts of biomass on rather small inputs (largely that needed for respiration and maintenance). If these systems developed over long periods of time in infertile landscapes, as in parts of Australia, they may not be easily replaceable once removed. Development, by setting back succession’s clock, makes the landscape shed more water, soil and nutrients. Some changes in a developed landscape are obvious, such as the replacement of forests by houses; changes may be less obvious in a landscape’s watercourses. We are used to modern single-channel rivers, which are largely a man-made creation. Long Island Sound looks beautiful in the moonlight today, despite the fact it is slowly dying from too much man-made nitrogen. This sometimes becomes obvious, such as in July 1987 when lobsters began to crawl up on shore, to avoid suffocation in water with essentially no oxygen. On some summer nights the sound gives off a whiff of hydrogen sulfide, from decaying fish that were trapped by the low oxygen levels (the recurrent summer anoxia). Soil and nutrient runoff from agriculture, nutrients from sewage treatment plants, from pet droppings, from suburban development, all flow into the sound. Its rivers, all dammed, no longer support healthy spawning populations of forage fish. (Alewife populations in the Sound have fallen to 3% of historical numbers.) So populations of birds and fish that depend on forage fish have fallen.

In general, under human settlement, water quality deteriorates. Surface waters become undrinkable. Ground water levels fall as landscapes are cleared and as aquifers are pumped for drinking water and irrigation. On farmland, productivity declines over time, as the nutrients stored in the soils by the former vegetation are used up by crops, by the increased microbial activity on ground warmed by the sun, are lost with eroding soils, are leached out by rain. Modern agriculture, even organic or regenerative agriculture, is hard on soils and some soils support it better than others. Rates of erosion of less than a ton of soil per acre per year are considered good (they are good, as they approach replacement levels that are, on average, half that, or about an inch every 250 years); 10 tons per acre is more usual, or a ton of soil for a ton of grain. Some of this soil ends up in roadside ditches, some in the atmosphere, some in waterways. Logging, mining, and grading for construction result in large surges of soil, nutrients, water, toxic metals and sulfates into streams. (Mining waste amounted to 10 tons per person—almost 40 tons per family—in the United States in the 1980s.) Grading destroys the soil’s profile and its nutrient structure, and thus changes its relationship with plants and with surface waters; under natural conditions the profile takes 1000 years to redevelop. (The process can be speeded up by planting deep-rooted grasses and shrubs.) Land development also affects the atmosphere; but the atmosphere lacks the discreetness of surface waters; mixing is more rapid, complete and global, so changes are harder to see; and effects may be remote from causes. In general, terrestrial changes must be large to have a measureable effect. Convective rainfall is said to be reduced by deforestation when it reaches 100,000 square miles (an area a little more than 300 miles on a side). Plumes of dust from the Sahara, or from spring plowing in China, measureable in Hawaii several days after it begins (the aluminum in the dust was the clue), affect both terrestrial and oceanic environments and the earth’s heat balance. Dust from the Sahara has increased 5 times since the 1970s because of drought and population growth in the Sahel; and from increased traffic over the desert, which breaks its surface crust of lichens or wind-swept gravel and exposes the sand below. The dust carries fungal spores and bacteria and may be a factor in the decline of some coral reefs. Rich in iron, the dust raises ocean productivity and the productivity of tropical forests. Enough dust in summer cools the surface of the tropical Atlantic sufficiently to reduce the frequency of Atlantic hurricanes. Some scientists claim that changes in land use in the Northern Hemisphere over the last 300 years, such as replacing forests with farmland, and building urban areas that act as heat traps, have raised the midwinter temperature of Europe by 3º C. and speeded up jet stream flow in the Northern Hemisphere by 6 meters per second. If true, such changes would rival those claimed for global warming. Forests in temperate regions tend to cool the atmosphere in summer, as water evaporating from their leaves absorbs heat. Turning forests into urban areas or farmland thus warms the atmosphere in summer. In winter, in snowy areas, forests tend to warm the atmosphere, since they absorb more sunlight than snow-covered ground. Boreal forests are thought to warm the atmosphere by about 1º C. in winter and summer. Locally, this warming is thought to be greater than the cooling caused by their absorption of carbon. Irrigation over a large area, as in the Central Valley of California, makes the atmosphere more humid, and thus changes the microclimate of both winter and summer, making summer more oppressive, and hiding the view of the Sierra from the coastal mountains, on which John Muir remarked. Most landscapes that we see as natural are in fact severely altered.

The effects of development on the ecological functioning of a landscape can be reduced. Belts of trees along streams, if wide enough and located properly, will convert much of the overland run-off of water into subsurface flow, catch topsoil, and reduce the nutrient levels in the run-off water. The suggested widths of such belts vary from 50 feet to 300 feet on each bank. Small trout streams, whose ideal water temperature is 55º F., need 200 foot buffers. (At 55º F. brook trout eat half their weight weekly, mostly in aquatic insect larvae; they eat less at higher or lower temperatures.) Such areas are most effective if they include any adjacent wet habitat, such as ponds, wet grassland, swamps, or wet woodland, that is connected with the river. The larger numbers usually involve larger streams (the natural floodplain of the Mississippi ranged to more than 100 miles in places); and the creation of a corridor through which larger animals (mountain lions, elk, wolves) can move, and in which shyer birds and animals (fisher, eagles, owls, some neotropical migrant songbirds, red-shouldered hawks) can breed. California coho salmon are at 1% of historic levels, and recent California regulations to protect coho salmon and steelhead trout call for a 150 foot buffer on each side of fish-bearing streams. Loggers must leave 85% of the canopy within 75 feet of the stream, 65% of the canopy in the remaining 75 feet. This lets them cut the largest trees, which may be useful genetically because they are fast-growing; and physically as nesting sites for raptors. All such regulations are compromises; and no protection was given for streams now without fish, or for dry gullies that carry water during the rainy season, and feed silt into streams. There was no provision for leaving some downed logs on the forest floor, where they act as dams, collecting soil behind them. (Generally, neat park-like forests are not natural.) Belts of undisturbed grasses also reduce the flow of nutrients and soil into streams, and may be a better choice than forest in some areas. If large enough, they provide habitat for grassland birds. Studies in Tenessee have shown that 6% of a watershed under contoured forest strips will cut the run-off from agricultural land in half; 30% to 40% of the land area in forest will transfer all the surface runoff to the subsoil and stop erosion from the area as a whole. One could conclude (in a compromise) that 20% of formerly forested agricultural landscapes should be in forest. Some of that forest must be downslope of the fields, which usually means it takes up farmland. In more developed areas, if drainage water is left in unmowed ditches rather than confined to pipes, the cattails and sedges that grow in the ditches will slow the flow of the water and capture the nutrients and silt; the microbes associated with the stems and roots of the plants will remove much of the metals, nutrients, and hydrocarbons in the water. Some of the water will sink into the ground, recharging local aquifers. Flashy runoff into the receiving streams, which excavates them and reduces their populations of invertebrates and fish, will be reduced, slowed, and cleaned. If necessary, the ditches can be periodically dug out and the contaminants removed with the soil. Such ditches function as settling basins, which otherwise (to be effective) must take up 1-5% of a developed watershed.
Strips of forest or grassland that intercept run-off water take up land of potential economic value. Wide strips change land use on large areas of lowland soil. Much of the de-nitrifying activity in soil water flow, which returns soluble nitrogen in the soil water to the atmosphere as nitrous oxide or nitrogen gas, occurs in wet, oxygen-poor environments near wetlands or streams. Sometimes these anoxic bands are wide, sometimes narrow. If not too much nitrogen is running off the landscape (from fertiliser, septic tanks, pet manure, car exhaust) sufficient streamside habitat can reduce it to reasonable levels before the run-off reaches the river. Phosphorus, which is usually carried by soil particles, is greatly reduced by a band of streamside vegetation, though less so in winter when the ground is frozen and the roughness of the silt-trapping surface litter reduced. (Heavy rains, which let the runoff form channels through the woods, also tend to overwhelm the ability of filter strips to capture phosphorus.) Most rivers in developed countries are supersaturated with nitrogen. Studies of the Platte River in Nebraska, whose watershed is lightly settled but heavily agricultural, indicate that it leaks nitrous oxide to the atmosphere along most of its lower course. The nitrous oxide is produced by microorganisms that live in the water from soluble nitrogen coming into the stream from cattle feedlots, fertiliser and human sewage. Nitrous oxide is a greenhouse gas that currently produces 5-6% of the man-made greenhouse gas effect (40% that of global transport), and which also contributes to ozone depletion in the stratosphere. Leaving wetlands alongside rivers keeps nitrogen out of waterways in more than one way: water flowing downstream moves in and out of riverside wetlands, where it is also cleaned of nitrogen. But the bacteria that chemically transform it can’t eliminate it; they must return it to the atmosphere as nitrous oxide or nitrogen gas. If it returns as nitrous oxide, it adds to global warming. With a growing human population most of whom depend on crops raised with excessive amounts of nitrogen fertiliser, ways of reducing nitrogen use become more and more important. (Agriculture in 2000 contributed 14.9% of anthropogenic greenhouse gas emissions, transportation 13.5%.) A more benign agriculture is possible, but may imply, among other things, a different diet.

The obvious reason why ecologically appropriate land development schemes aren’t more popular is that they are seen as limiting income to the landowner. This is often true, and will probably remain true until ecological resources are given a value in capitalist economies. Unless the water that runs off his land has a value, no benefit accrues to the landowner from reducing the downstream impact of his land use. He may however benefit from land-use changes upstream. (Australian farmers help subsidize the planting of trees to lower the level of salty groundwater on lands upstream of their fields; their payments are based on the transpiration rates of the trees; lowering the level of salty ground water keeps the river water, used for irrigation, less salty.) And using vegetated drainage ditches rather than pipes for runoff water saves a developer money (perhaps $800 a house) as well as improving the quality of the runoff water (an environmental benefit). Since more water sinks into the ground, less irrigation is necessary for trees. Narrower side roads, less expensive to build, slow traffic and allow the tree canopy to close over the road, cooling the street and its houses, and saving the homeowners money on air conditioning. The additional cost of grading so roof and driveway runoff is captured in depressions, where it sinks into the ground, is insignificant. Building better insulated houses, with more efficient appliances, more efficient lighting, and properly sized, efficient heating and cooling systems, together with installing solar panels for generating electricity, increases the initial cost of the building, but lowers the buyer’s monthly payments for electricity, heat, hot water, air conditioning; thus the buyer can afford the more expensive house, which has a lower impact on the landscape as a whole. The builder’s profit and that of the bank, which depend on total cost, are greater. (In general, energy-efficient houses, warehouses, buildings with low energy intensity manufacturing, and one-storey offices and institutional buildings receive enough solar energy on their roofs to power them if the energy could be captured and converted.) Undeveloped areas along streams take up buildable land, especially if they are wide enough so a variety of birds and animals can survive, and if parts of them are left without paths, so their purpose is to remain a bit of wilderness as well as to protect the stream. Such lands also flood and are often wet, expensive to develop, and unsafe or unpleasant to inhabit. Developers can be compensated by letting them increase the density of buildings away from streams. And the presence of the natural area is likely to raise property values. For farmers, land taken out of production probably constitutes a loss. The unfarmed land may allow them to farm more successfully, by providing habitat for native insect predators and pollinators and for birds and mammals that control rodents. The trees or grasses the land produces may be useful on the farm. (In the South, pine straw collected under mature pine forests, is marketable at garden centers.) Undisturbed prairie or forest is worth $20 to $100 an acre a year in sequestering carbon. Natural land also has a public value in cleaning and storing water. (Farmers could bid for contracts to provide these services.)

The esthetic of landscapes has a moral aspect. Ecologically preferable landscapes, often not very picked up, tend to conflict with ideas of what is right: the messy and dangerous wilderness versus the settled landscape. Drainage ditches with cattails and frogs are considered unsightly (they may also have mosquitoes). Neighbors sue each other over lawns of unmowed prairie grasses and stuff fliers from chemical companies into the mailboxes of homeowners whose lawns are bright with spring dandelions. Hanging out laundry to dry, or raising chickens, is illegal in many neighborhoods. Subdivisions in the southwestern United States have by-laws that forbid the use of solar panels on roofs; like laundry, the collectors are thought to depress property values. The appearance of the human landscape is as much a moral as an esthetic matter, perhaps more so: one’s landscape, like the interior of one’s house, is a reflection of one’s self. A certain evolution of the landscape took place in the United States, which was considered the right one: the primary forest was cut and became farmland and pasture. In nineteenth-century prints the dark forest surrounding the stumpy field steadily recedes to sunlit pasture and meadow, and the rough log cabin becomes a two-story Greek-revival farmhouse, sometimes with a seedling elm at the corner. Empty prairies became grainfields. The emptier plains, the North American steppe, now grows irrigated grain if water is available; or is used for dryland farming and cattle pasture if it is not. Cattle, wetland animals, hang out near water and exert their own ecological pressure on the landscape, destroying streamside vegetation, eroding streambanks, polluting streams and altering the plant cover of the uplands. The regrowing forest is cut when profitable, generally without interim stand improvement. Such management may more or less work ecologically and economically in some forests, such as the sprout hardwood forests of northern Pennsylvania, which were never farmed, and are now cut at relatively short intervals for hardwood flooring and furniture. Hardwoods that sprout from stumps, such as oak, cherry and maple, have replaced the primary mixed forest of northern hardwood, hemlock and white pine that Audubon visited. The forest is not allowed to mature biologically. This is regarded as a good thing, as many old trees are partly rotten, so letting trees mature beyond the point of maximum economic return is wasteful. The lack of mature forest changes nutrient relations among parts of the ecosystem, but the landscape is still more or less covered with trees (invasion with grasses and ferns, probably because of the heavy cutting and of browsing of tree seedlings by deer, is a problem), and depending on how heavily and often it is cut, the forest may still have a reasonable hydrological relation with its watercourses and a reasonably tight internal nutrient dynamics. The economic value of the forest remains high, though not as high as it would be if let mature further. (Over half the commercial forests in the United States are under 55 years old; 6% are over 175 years old: that is, they approach the age of old growth for eastern trees.) In all the young, cutover forests of the Northeast, the South, the upper Mid-West, and the Appalachian highlands, the development of new logging machinery, along with products like chipboard and finger-jointed lumber, has made possible the exploitation of wood of lower and lower value. The new harvesting machinery and end products compensate for the lower value of the logs and their lower density in the forest. That is to say, the return to the logger has risen, and manufacturers continue to profit, but the profit for the landowner, measured per acre of land per year, has fallen; and the landscape is much more heavily used. In woods clear-cut at short intervals, such as Midwestern aspen, Southern pine, and Maine spruce-fir forests, no mature forests, nor the plants, birds, lichens, mosses or amphibians associated with mature forests, survive, and the streams in small, frequently logged drainages are ruined by siltation. Nutrients that would be returned to the soil in fallen logs or leaves are removed as whole trees. How sustainable such practices are in the long term is hard to say. Long enough, if studies of a light sandy loam in Montana are correct: the soil contains sufficient mineral nutrients to sustain current logging practices for 100,000 years: that is, until long after the climate has changed and the trees disappeared. Soil nutrients are not the whole story, and how fast the trees grow after a few rotations, the cumulative effect of successive clear-cuts on soil fungi, insectivorous birds, insect grazers, and on the waterways that flow out of the forest, are less clear. The effects on streams are disastrous. Clearcut, west-facing slopes in sunny, dry western forests can be almost impossible to reforest, once the mycorrhizal fungi that support the trees’ growth are gone.

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After the Second World War, settlement along the Atlantic beaches of the United States grew. Houses were also built along the beaches and atop the bluffs of the Pacific coast. Neither of these areas is stable in the long term, the long term here being several decades to several centuries. Atlantic beaches move inland at several feet a year, 6 to 8 feet on the Outer Banks of North Carolina, that is 60 to 80 feet in 10 years, something lighthouse builders knew; the average for east coast beaches is 2 to 3 feet a year. While moving inland, the beaches retain their approximate slope and width. Bluffs on the Atlantic side of Cape Cod retreat about 2 feet a year; again the shape of the bluff and of the beach below remains similar. So the path Thoreau took on his walk along the Cape in the mid-1800s is now some hundreds of feet offshore. The cause of this movement is wave action. Waves are created by winds. Winds are powered by the sun and the earth’s rotation. Breaking waves transfer their energy to the beach, moving it around. Since waves rarely hit the beach at an angle of exactly 90º, their impact creates an alongshore current that carries sand with it, generally south along the East Coast. This alongshore movement of sand drives the beaches inland. On any given beach, sand also tends to move back and forth between offshore sandbars, formed in storms, and the beach, replenished in calmer weather. Such movement, together with the particular sea-floor characteristics, geology, tidal action, and weather of a given site, help the beach keep its characteristic shape. Despite the alongshore movement that brings in more sand, there is a continual net loss of sand to the deep sea. Some is lost in inlets, where the sand is caught up in tidal flows and deposited inside or outside the beaches; some simply flows down by gravity into submarine canyons. In the modern world, inlets are dredged and the sand is dumped offshore. New sand comes from rivers and eroding headlands. On the East Coast, most of the riverine sand is deposited in estuaries behind the barrier islands and only slowly, if at all, makes it to the beach. The estuarine marshlands that receive the sand help hold the barrier islands in place. Most east coast rivers are now dammed so their load of sand is greatly reduced. (Sand being heavier than silt, it settles out preferentially behind dams.) Along the East Coast most new sand is supplied by eroding bluffs and cliffs. Armoring cliffs to protect clifftop homes prevents the generation of new sand. Armoring beaches with jetties and groins prevents the alongshore movement of sand, starving beaches downstream, which then shrink and recede. Armoring beaches with seawalls to prevent the loss of buildings that were built too near the sea, results in the total loss of the beach outside the wall. In California, the rivers that flow through the steep, erodable hills of the California coast ranges match headlands as sources of sand. Damming those rivers traps much of the sand behind the dams. Dams and channelization along the Santa Clara River reduced its estimated input of sand to the beaches of Ventura County from 600,000 cubic yards of sandy sediment a year to 150,000 cubic yards. It is thought that dams on California rivers now hold back something like 100 million cubic yards of sand annually. Beaches are also changed by catastrophic events; the 1938 floods along the Santa Clara brought down an estimated 8 million cubic yards of sediment, building up beaches downstream. Armoring California’s sea cliffs to protect houses or roads also prevents the creation of new sand. So beaches shrink; and eventually change their profile. (In general, they become more steep.)

The notion of sand rights, thought up by a lawyer named Katherine Stone, is based on a provision of the Institutes of Justinian, a summary of Roman law compiled in the sixth century. The Institutes stated that any Roman citizen had a right to use shorelands or riverbanks to fish, tie up a boat, or unload cargo. This provision of Roman law was taken into English common law. Common law was taken by the English colonists to America and became state law when the colonies became states. The notion is now known as the Public Trust Doctrine. Through the doctrine, a state has an interest in protecting shorelands, bottomlands, tidelands, navigable freshwaters, and their plant and animal life, for the use and enjoyment of all the people. Individuals may own such lands, but the interest of the state in them is inalienable, and when the state takes steps to protect or manage these resources it does so with the rights of an owner, not a regulator. Thus in theory no compensation is owed to the landowner. The public interest in such resources can be terminated, but only narrowly, and only in pursuit of a public interest that is judged to be greater. Thus construction for navigation, or for unloading of cargoes has been allowed. (In general, more development has been allowed than is consonant with modern interpretations of the Doctrine.) The Public Trust Doctrine has been expanded through lawsuits to include rights such as strolling, swimming, the esthetics of the shoreline, and environmental health. Out of these rights come the public right of access to the “wet” beach, the intertidal beach, in all coastal states except Massachusetts and Maine, where such rights were extinguished under the charter of the Massachusetts Bay Company. In some states, such as California, the public also has a right to a portion of the dry beach, over which passage is necessary to reach the wet beach.

The Public Trust Doctrine was the basis of the ruling that made the city of Los Angeles reduce the amount of water it was taking from Mono Lake. Mono Lake, in the desert east of the Sierra Nevada, receives run-off from the eastern side of the Sierras. A California state court found that the lake’s wildlife constituted a public trust whose needs must be balanced with the need for water of the citizens of Los Angeles, who had purchased the water rights to Mono Lake. By the same token, if there are to be fish, there must be limits on water use and on water pollution; and if there are to be beaches, there must be sand. If the right to the shore is a common right, then so is the right to the sand that feeds the beach. States have not moved to regulate development so as to protect the rights of beaches to sand, but have left redress to property-owners and municipalities, who file lawsuits to address the matter. Such suits have generally been upheld in state courts, where the expansion of the Public Trust Doctrine has occurred, but have never come before the Supreme Court of the United States. If enforced, sand rights would force people to make a more accurate assessment of the costs of beachfront or clifftop development; of navigation works; and of dams. Dams provide water for irrigation; for commercial and residential use; for hydropower; they provide for river navigation and flood control. They also destroy fisheries, increase the river’s production of methane, change the ecological functioning of rivers and riverside wetlands, and intercept the flow of sand to beaches. Strictly speaking, the beneficiaries of dams, that is, cities, industry, agriculture and river navigation companies, should pay to rectify the damage to beaches, marine lands, and riverine and offshore fisheries. Dams can also be operated so as to reduce such damages; this would benefit everyone.

Sand rights are a powerful idea because they connect uplands with ocean beaches in a working physical system. Such connectivities are common in nature but little recognized in biological theory. Before modern times and the saturation of once nitrogen-limited forests and grasslands with airborn nitrogen (a product, like carbon dioxide, of combustion and of agriculture), ammonia volatilized from seabird droppings is thought to have constituted a major atmospheric input of nitrogen to terrestrial environments; the input was substantial where seabirds nested along coasts, such as in parts of Alaska, the Pacific Northwest, and New Zealand, where it contributed to the growth of grasses and trees. Lightning was another atmospheric source of nitrogen, and helped fertilize the plains. (The main source of terrestrial nitrogen is nitrogen-fixing bacteria in the soil.) Including the natural environment as a whole in the Public Trust Doctrine would give one the regulatory tools to create, or re-create, a world in which people fitted into the working natural environment. To once again paraphrase Locke, the ecosystem services a landscape performs constitute its greatest intrinsic value, and thus justify regulating the economic world that affects them; in other words, this is another example of markets requiring adult supervision. Many degradations of the environment are difficult to sue over, since specific causes are difficult and expensive to establish (the specific source of that chemical, or that fertiliser runoff); and many have been aggravated by government action in the economic interests of owners of riverfront or shoreline property. Should the fisherman of Texas and Louisiana sue Iowa farmers for the condition of the Gulf of Mexico? Should Louisiana trappers and property owners sue oil companies for the disappearing Louisiana wetlands? (Over 10,000 miles of oil exploration canals increase erosion in the Delta.) Should fisherman along the Mississippi sue riverside farmers, or the Army Corps of Engineers, the body responsible for the river, for the loss of overflow wetlands? Is navigation up the Missippi to Minneapolis, up the Missouri to Sioux Falls and up the Ohio to Pittsburgh, a necessary use of those waterways? The annual barge traffic between St. Louis and Sioux Falls is worth $7 million; 93% of the emergent wetlands, backwaters, and sloughs along the Missouri have been converted to agriculture or dredged for channels in constructing the waterway; the shape, chemistry, and temperature regime of the River have been changed; non-point, largely agricultural, contaminants such as chlordane, dieldrin, and PCBs are a hazard to fish and wildlife in the remaining floodplain and the channel; use of the river by ducks is way down and the fish catch along parts of the river has dropped 80%. If people have a right to clean air, should the inhabitants of New York and the New England states sue power plants in Ohio and West Virginia for the condition of their air? (This has happened.) Or the Inuit of Nunavut sue chemical plants in Alabama for the state of theirs? (The source of some of the chemicals in their bodyfat has been traced to chemical plants there.) Ground water moves, air moves, and if one looks far enough most things on the planet are connected. Including the natural environment with its ecosystem services in the Public Trust Doctrine provides a way, in our litigious society, to reach a working natural environment; a sort of public property right that includes the environment as a whole. The idea of rights to natural goods are not new: Egyptian cities had laws regulating the heights and placement of buildings, to preserve other people’s rights to sunlight and air. Under English common law, property owners have a legal obligation to not use their property so as to inflict legally recognized injury on others; does this obligation include such things as lawn chemicals, that flow off with the rain and drift on the air?

Human use of the landscape runs along a continuum. Industrial civilisation has to convert some of the landscape to human use, but not all of it. The economics of property ownership will make us use all of it. Sand rights tend to pit one form of development against another. Sand rights have the potential to transform some land uses because loss of beaches brings into play financial interests that dwarf those of fishermen or conservationists. In fact, we would be better off if there were no development along beaches, in the floodplains of rivers, or on top of seaside bluffs. A reasonable, long-term, national, land-use plan would phase such developments out through buyouts and the termination of federal guarantees for flood insurance. But any land development affects watercourses. Once impervious surfaces reach more than 10% of a watershed, streams suffer. (Impervious surfaces are usually thought of as roofs, roads and parking lots, but plowland is several times as impervious as grassland or forest, and mowed lawns are also relatively impervious surfaces.) The problem is the rush of water that comes off such surfaces in a rainstorm. The heavy flow causes channelization and sedimentation in the streams that receive it. When impervious surfaces reach 20% of surface area, only the hardiest species in the streams receiving the drainage water survive. In parts of New Jersey, impervious surfaces now approach 60% of the landscape, and flooding is a constant problem. Such problems can be ameliorated by modifying the pattern of human settlements. Settling ponds and artificial wetlands reduce the pulse of water reaching streams and trap silt, debris, and pollutants. If the drainage water flows to these ponds and wetlands in vegetated ditches rather than pipes, the structures work better. Some of the flow can be returned to ground water, which is usually considerably lowered in developed areas, through the use of catch basins. Catch basins require 5% to 10% of the area from which the runoff comes; so a roof of 2000 square feet would require a catch basin of 100 to 200 square feet, say a shallow hollow 6 to 12 inches deep and 12 feet on a side. Catch basins work best in sandy loams with a high organic content. Such basins are planted with vegetation that can stand periodic flooding. Larger areas require approximately one basin per acre for runoff water. An acre requires a basin of 235 to 475 square feet, or a hollow about 20 feet square. Connected drainage areas in the backyards of older, steeper urban developments would take care of roof and lawn run-off; road and sidewalk run-off would require other solutions. Permeable pavements on parking lots and roads let much runoff filter in; parking lots and roads can also devote 10% of their area, such as shoulders and medians, to catch basins, vegetated with cattails, giant reed, or shrubs and trees. Much of what comes off roads and parking lots is relatively toxic and includes motor oil, antifreeze, copper from brake linings, cadmium from automobile greases, and various toxic organic chemicals and particles from automobile exhaust and tire dust. Catch basins and artificial wetlands capture and process some of this before the water reaches streams. Such structures can be added when roads are rebuilt. A common location for recharge structures in new developments is the strip between the sidewalk and the road.

An ecological perspective puts us all in the same boat; we are all absolutely dependent on each other no matter who owns what piece of land. And the connections in the modern world are global; through the currents of the seas, the circulation of the atmosphere, the ships and planes of trade. Some landscape-changing organisms have been introduced to new environments deliberately, such as pigs, grasses, rats, bamboo, and mongeese to Hawaii. Some arrive on their own, with aircraft (snakes that hide out in wheel wells, mosquitoes in cabins), in packing material (wood-boring insects), in food (snakes, fungi, insects), in ship ballast water (larvae of many marine fish and invertebrates). Use of private land can be controlled by regulation, or by economic incentives, such as tax reductions or annual payments. Land in developed countries is still relatively cheap compared to national incomes or social costs. In the United States a program to purchase lands essential to ecosystem services, such as floodplains, overflow lands, wetlands, streambanks, large tracts of native wildland, coasts subject to tidal surges, would cost comparatively little. As with shifting to a low carbon, non-toxic economy, a long-term program is needed. A small annual appropriation, say $10 billion a year, for a century, would give the 3000 counties in the United States $3.3 million dollars a year to purchase lands. If land costs $3,300 an acre, a county could purchase 1000 acres a year, if $500 an acre, 6,500 acres. (In New York State, with 60 counties, this would result in perhaps 20 million acres of land being protected, or more than doubling protected landholdings. More importantly, the lands would be spread in low-lying ecosystems throughout the inhabited state, in places where much of the population lives.) Precedents exist for programs with willing sellers. Committees of ecologists, soil scientists and geologists would come up with lists of suitable lands; local environmentalists, land developers, farmers and other stakeholders would decide what lands to buy; an existing federal agency like the Soil Conservation Service would administer the program. One problem will be the loss of property taxes to localities. But any serious look at land use in the United States has to address the question of property taxes, which now are asked to support many more services, including medical care for the poor and schools, than they should. Three quarters or more of county budgets in New York State, supported with monies from property taxes and sales taxes, go for social services. Such costs must be shifted to a larger base, if only because basing social services on such taxes results in tremendous inequality among counties. Conservation Reserve payments to farmers are an expensive way to pay for the maintainance of ecosystem services (after 10 years, payments often amount to the purchase price of the land), but help keep small farmers on the land, and since the landowner continues to pay property taxes, have the advantage of shifting payment for local services to the federal government.

The adoption of agriculture made human use of natural landscapes more exploitative, though the effect on natural environments varied. (I would argue the ‘end of nature’ came with settled agricultural landscapes, as the natural world became commodifiable, and was more useful as fields, or as a source of timber and minerals, than as a landscape that provided food.) Some systems such as Tiahuanacan raised beds, Mayan ditched swamps, the shifting slash and burn agriculture of the tropics or the temperate zones, were sustainable indefinitely, as long as they weren’t overused. While these systems changed their surroundings, they didn’t degrade them. A large part of the sustainability of these systems depended on extensive areas of nearby land remaining more or less undisturbed. The natural vegetation was necessary to sustain water flows, to renew soils for slash and burn farmers, to conserve fisheries, to reduce erosion, and to provide other things of economic value: medicines, foods, building and basketry material, fodder. Upland agriculture that used permanent cleared fields, and large-scale irrigated agriculture, tended to have more serious ecological effects, though as long as populations were small and technologies low, economic destruction of whole landscapes took much longer than at present. “High” civilizations grew continually in population and their demands for raw materials, food, and fuel stressed their agricultural systems and the surrounding uncultivated lands, which were cut over, pastured, or brought under agricultural development, often with disastrous consequences (soil erosion, soil nutrient depletion, flooding, waterlogging, soil salinization, drying up of streams, growth of deserts; grazing animals turning upland forest into rocky scrub). Upland agriculture can work within a larger ecosystem, and not degrade its surface waters or its soils, if its sites are limited and its methods take account of the larger environment. The Amish of Pennsylvania and Ohio, who farm with horses and use no manufactured fertiliser or pesticides, have left their soils more fertile than they found them. Modern no-till agriculture, which keeps the soil surface constantly covered, reduces soil erosion by 75- 90%, and nutrient losses by similar levels. Soils under no-till store atmospheric carbon and slowly rise in fertility. In general, the demands of larger and larger populations have made people force certain patterns of settlement on landscapes; the energy supplied by fossil fuels and the accumulation by societies of enormous reserves of capital has made this process faster, more intensive, and more extensive. Landscapes have not been settled with their own, that is, the landscapes’, interests in mind since the development of large settlements 8000 years ago. But human settlement for the last 6 to 8 millennia has always existed along a continuum of use. Until recently (1860? 1900? 1950?) many parts of the world remained relatively untouched by agriculture or industry. Eugene Odum thought we should leave 40% of any landscape undeveloped, to allow room for nature to work. In many North American landscapes this is no longer possible, though such matters can be (somewhat) reversed. Without intervention, it is the ineluctable fate of every piece of private land in a market economy to be developed. The nature of the economy, together with our current property tax system, force this upon us. Development is the only rational use for land in the modern world.

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What made our world possible was the exploitation of fossil fuels. Fossil fuels freed us from the cycles and limits of natural production, and so the limits on what was possible vanished. The use of fossil fuels made possible a tremendous expansion in the human habitat and population. But the use of fossil fuels did not change our dependence on nature; it simply changed its dimensions. Fossil fuels are thought to have been laid down several hundred million years ago, on a warmer planet, with an atmospheric carbon dioxide level 2 to 5 times ours, and an oxygen level of 1.5 times ours. The rate of photosynthesis may have been several times ours. The carbon dioxide in the atmosphere was turned into plant tissue, and that tissue preserved in great wetlands, as hard coal. (Brown coal developed more recently.) Oil arose as massive algal blooms in shallow seas. (While some scientists think oil is not derived from plant tissue, but from organic chemical reactions deep in the earth’s mantle, the more general view is that oil is derived from phytoplankton that settled to the bottom of shallow seas.) The carbon dioxide that was removed from the atmosphere by the formation of oil and coal resulted in a substantially lower level of atmospheric carbon dioxide; partly, this has created our cooler modern planet. Partly, because carbon has also been stored in forests and grasslands, in soils, in ocean sediments, as methane in frozen Arctic tundra, as methane clathrates under shallow polar seas, in the immense amounts of carbon-demanding rocky debris created by the Himalaya’s pushing up the Tibetan Plateau, and because solar radiance, the aspect of the earth to the sun, and the positions of the continents on the globe also affect climate. Changes in all these have influenced the last 200 million years. Fossil fuels, limestones, phosphate deposits, coral reefs, soils, the composition of the atmosphere, some iron and copper deposits, are all manifestations of life. The deposits of iron ore that made the Industrial Revolution possible began to be laid down about 2.5 billion years ago, when the first photosynthesizers (green algae and blue-green cyanobacteria) started to raise the oxygen content of the atmosphere. The soluble iron in the oceans precipitated out as deposits of insoluble iron oxides: rust, or iron ore, which we heat in the presence of carbon to eliminate the oxygen and so produce iron metal.

In our use of fossil fuels we are completing a circle. We are returning the stored carbon in fossil fuels to the atmosphere as carbon dioxide. Sooner or later this would have happened anyway as the planet’s surface was slowly recycled through the mantle. While this process takes tens to hundreds of millions of years, industrial combustion will take less than a thousand. By warming the planet, the carbon dioxide is returning it to an earlier state. This has happened before. About 55 million years ago the intrusion of molten magma into mudstones under the Norwegian Sea, and perhaps also into coal deposits in South Africa and Antarctica, decomposed the solid carbon into methane. This methane release was accompanied by the release of carbon dioxide from volcanoes and as the ocean warmed a few degrees, by methane from underwater clathrates. Perhaps 1200 billion tons of methane, of the 10,000 billion tons thought to be stored in clathrates in the permafrost and under the seabed (twice fossil fuel reserves), were released. Global temperature warmed about 13º F. over 30,000 years—some say in a much shorter time—then fell as massive algal blooms in the ocean, fed by the rising temperatures and the increased nutrients running off the land from the increased rainfall, absorbed the carbon and returned it to ocean sediments. The complete cycle took about 60,000 years, or 6 times longer than agricultural civilization has so far lasted.

Similarly, metal smelting and the burning of fossil fuels are distributing metals and oxides of sulfur and nitrogen over much of the terrestrial landscape, slowly making it less hospitable to the current vegetation. Other industrial chemicals, such as the chlorofluorocarbons and compounds of bromine, released in relatively small quantities into the atmosphere, have reduced the effectiveness of the stratospheric ozone layer that shields the planet’s surface from ultraviolet radiation. The development of an ozone shield a very long time ago was one of the things that made life on the surface of the earth possible. The chemical reactions that deplete ozone take place at very low temperatures at the end of the polar winter, with the returning sun. The carbon dioxide-mediated greenhouse warming of the lower atmosphere necessarily cools the upper atmosphere (the stratosphere), since only so much heat is radiated out from the earth. If more is captured by the lower atmosphere, less is available to warm the upper atmosphere. The cooling of the upper atmosphere, by favoring the reactions that deplete ozone, reinforces the effect of the ozone-depleting chemicals. (It also makes the stratosphere more dense, allowing satellites to stay up longer.) By poisoning soils and waterways with nutrients, heavy metals, and chlorinated hydrocarbons; exchanging calcium in forest soils for metals like aluminum; by increasing ultraviolet radiation at ground level (UV-B is up 15-20% at 40º North Latitude, the latitude of the Pacific Northwest, southern Canada, New England and upstate New York); and warming the planet at a rate too rapid for many organisms to adapt to, we are changing the conditions under which current life exists. We are making the world more hostile to organisms like us, but perfectly suitable for bacteria and other micro-organisms that evolved in more hostile worlds and whose rates of reproduction (minutes, hours) let them rapidly evolve to take advantage of new conditions. If we left for Mars, few organisms would miss us (cows, cabbages, ragweed); but the departure of green plants, insects, or micro-organisms would mean the end of the biosphere.

Carbon dioxide is not the only greenhouse gas that raises the temperature of the lower atmosphere. The other greenhouse gases equal it in effect. Nitrogen fertilisers are decomposed by soil bacteria to release nitrous oxide to the atmosphere. Nitrous oxide is another greenhouse gas, though one with a shorter residence time in the atmosphere than carbon dioxode. It would be hard, but not impossible, to feed the current world population without the use of nitrogen fertilizer, but its use could be cut substantially. About 40% of the nitrogen fertiliser used in the United States is used on lawns. There, use could be cut to zero. Composts, applied to mixes of grasses and low clovers, produce a healthier lawn. Methane from coal mines, from leaky natural gas pipelines, from irrigated or flooded lands, reservoirs, human sewage, and the guts of ruminant animals (cows, goats, moose, sheep), also helps warm the planet. People have probably doubled its concentration in the atmosphere. It would be relatively easy and inexpensive to cut methane emissions substantially, and cutting them would have a substantial effect on global warming. The chlorofluorocarbons that cause ozone depletion are extremely potent greenhouse gases and so have an effect on climate even at their current miniscule concentrations; the chlorofluorocarbon refrigerant that most affects the ozone layer has been banned in industrialized countries, but use in the underdeveloped world continues. Other new, similar compounds that cause warming (fluoroform, nitrogen trifluoride) are let accumulate until sufficient pressure arises to control them. That such chemicals are likely to be harmful is no secret.

For the rest, soot (from burning coal, from burning wood and dung in cooking fires in the third world) absorbs sunlight and warms the air around it, and when it settles out on glaciers or sea ice, helps it melt. Its contribution to global warming may be substantial. The many cancer-causing and mutagenic compounds of combustion, the neurotoxic metals, the chlorinated hydrocarbons that mimic human hormones, cause cancers, and interfere with fetal development, enter the food chain through air or water and are concentrated as they move up it. Fat soluble, they are stored in the fatty tissue of plants and animals. Such chemicals are lost during nursing and excreted in faeces. We can hope these chemicals will provide more food for bacteria, which will decompose them and thus render them (probably) harmless, that is, harmless to us, no longer useful to the bacteria. Earthmoving by people, now estimated at 40 billion tons per year, surpasses estimates of material released from seafloor volcanoes, and is comparable to the earth moved by rivers. This material is a source of more nutrients, metals, dust and acids that end up in the atmosphere or water. (On a more cheerful note, the mass of material also soaks up carbon dioxide.) Our effects on nature are no longer limited to matters like the misuse of agricultural soils, or the unsustainable harvesting of renewable products like fish or timber, though these remain, but include global temperature, global sea levels, levels of calcium in soils, and levels of toxic materials in animals such as the beluga whales in the St. Lawrence estuary, dolphins in the North Sea, common loons in Maine, and humans. Many of the current effects of human development are subtle, and invisible to the naked eye.

Economics has given us this world and, under the right direction, economics can take it away. I would like to consider settling a landscape with the landscape’s interests in mind. That is to say, suppose a landscape were settled so that its native ecosystems, or some analogue of them, continued to work, so that settlements didn’t pollute the streams that ran through them, or unduly disturb their temperatures or patterns of flow. Biologically speaking, this means keeping much of the native nutrient recycling systems in place. (We are talking of bacteria, soil invertebrates, soil shading and root-holding systems here, not necessarily old growth and wolves.) Of course this is only partly possible in agricultural or logged ecosystems, or in suburbs, and may not be possible at all in more heavily settled locales. Places like Manhattan must control their nutrient output, and their interference with natural patterns of water infiltration and flow, with industrial technologies like sewage treatment plants, storm water treatment plants, the use of man-made marshlands to strip the waste water of its remaining metals, nutrients, hydrocarbons, hormones, bacteria, viruses. Urban storm water may contain nutrients on the level of sewage effluent. Use of low flush toilets and low flow showerheads greatly reduces wastewater flows and lets sewage remain longer in treatments plants, greatly reducing the nutrient load of the outlet water. The sewage treatment plants of New York City constitute Long Island Sound’s fourth largest freshwater tributary. Constructed salt marshes are cheap at $20,000 per acre. Reducing car use in urban areas helps. In general, reducing combustion helps. So, too, does composting food waste and installing solar electric panels. Ultimately, discharges from urban systems must be converted to inputs that sustain local or distant ecosystems. The city itself will not work well as an ecosystem, but relationships are possible: between peregrine falcons and pigeons; Canada geese and parklands; between parklands and migrating birds; the use of sewage sludges on Southwestern farmlands, or on strip-mined land; of processed urban urine as nitrogen fertiliser anywhere. Ecosystems and their animals and plants are resilient and adaptable. Striped bass now spawn under the piers in New York City, whose removal (for this reason) was halted. Oxygen levels in New York Harbor have recovered to the point that wooden pilings are attacked by marine boring worms and blue crabs are caught in Newtown Creek. A system of animal overpasses and underpasses, together with more protected habitat, might let foxes, mink, weasels, barred owls, salamanders and frogs occupy more of their natural range in the counties surrounding the city, perhaps reducing the white-footed mouse populations that carry Lyme disease. (For unknown reasons, deer ticks in parts of California with good fence lizard habitat—and many fence lizards—have almost none of the bacteria that carry Lyme disease.) Energy efficient, non-toxic green buildings cost slightly more to build but have operating costs 8-9% lower and produce a 6-7% greater return on investment. A city can reduce its impact on the surrounding ecosystem to tolerable levels, even if the effects of dense human settlement are capable of only so much amelioration.