The Next Species: The Future of Evolution in the Aftermath of Man

by Michael Tennesen

  Rothamsted Research has tested soils at several sites in the Amazon and found that terra preta took up, integrated, and retained carbon from organic matter much more freely than typical native soils, and this was one of the reasons for increased yields.

  Perhaps this would stave off starvation.

  THE KING COTTON FIASCO

  On another trip much farther north, but still looking at dirt, I traveled with Dan Richter, professor of soils and forest ecology at Duke University, and several of his faithful graduate students in a caravan of cars heading south from Durham, North Carolina, and the Duke campus to the Calhoun Experimental Forest, one of Richter’s favorite field sites. Located in Sumter National Forest near Union, South Carolina, the Calhoun was established in the 1940s to study the serious problems the region had with its soils.

  Richter worked in the Piedmont area of the southeastern United States. Here, years of Southern cotton production on farms and plantations in the 1800s had eroded earth, extracted vital nutrients, and greatly diminished the productivity of the region’s soils and ecosystems.

  The Calhoun’s initial location was picked to represent the “poorest Piedmont conditions” of agricultural soil erosion and cropland abandonment. Early studies on the Calhoun were aimed at soil improvement and watershed restoration in order to find the cheapest, quickest, most effective ways to improve tree growth and soil structure and to increase soil fertility for plants. Duke University’s long-running collaborative study with the US Forest Service has aimed at monitoring, sampling, and archiving information.

  The Piedmont is a plateau region of the Eastern United States between the Blue Ridge Mountains, the eastern range of the Appalachian Mountains, and the Atlantic Coastal Plain. It stretches from the state of New Jersey in the north to Alabama in the south. It is an area of about 80,000 square miles (210,000 square kilometers), and the soils in this region are predominantly clay and moderately fertile. In the central area of North Carolina and Virginia, tobacco is the main crop, while in the north, the focus is on orchards and dairy farming. In the south, where cotton was the chief crop in the 1800s and early 1900s, all that is left, said Richter, “is one of the nation’s most degraded landscapes.”

  He took us to a place in the forest where the soil had been excavated, exposing its profile. In the caravan there were a number of Asian students, including several from China who were eager to absorb the lessons and apply them to similar problems in their own country. China has long-term soil plots that are twenty and thirty years old “and they test soil and crop changes in a wide variety of soils to the major agricultural inputs, organic and inorganic,” said Richter.

  He noted that only 150 years of Southern cotton production had caused the erosion of as many as eight inches of topsoil across the southern Piedmont. Native forest was coming back here as it has in the northeastern part of the US, and this was currently restoring some of the organic matter, but the region was still deficient in many vital nutrients, including nitrogen and phosphorus.

  These are still agriculture’s two most important fertilizers. Though most crops need a lot less phosphorus than they do nitrogen, the smaller amount of phosphorus is critical to the mixture if you want to get robust growth. Nitrogen can be produced artificially, but phosphorus has to be mined, and the process is ugly.

  West-central Florida produces much of the US phosphorus and most of that is taken along the Bone Valley Member of the Peace River Formation, one of the richest sources of the mineral in the world. Miners create what looks like iridescent volcanoes from above as they pull phosphorus ore out of the ground, crush it, and process it into acid lakes. There, the ore is separated into gypsum, which forms the volcano-like cone and the fluorescent green acidic liquid. Farmers use that liquid in a dry mineral form to feed their crops.

  The trouble with phosphorus mining is the occasional breaking of these cones, which can spill into the Peace and Alafia Rivers, delivering the spillage to Charlotte Harbor or Tampa Bay. Here, phosphorus contributes to algae blooms, which depletes the oxygen in the water and asphyxiates the fish.

  “If you inventoried the world’s reserves of fertilizers, you’d find that phosphorus is by far the most limited in supply,” said Richter. “By some estimates of known deposits we have maybe fifty to one hundred years of it left. Lots of ecosystems are limited by phosphorus, yet lots of our surface waters are currently polluted by it. It is second only to nitrogen in the amount applied to agricultural lands, and it is a critical resource for corn, cotton, rice, wheat, and other grains. Without it, these crops won’t grow to their potential.”

  Still, nitrogen is the biggest problem right now, not the shortage of it, but its overwhelming presence in all of our soils. William Schlesinger at the Cary Institute of Ecosystem Studies told me, “Since World War II, synthetic production has doubled the amount of nitrogen on the planet, and that has seriously changed the chemical environment that a lot of species have evolved in.”

  Nitrogen is created by the Haber-Bosch process, developed by German scientists before World War I, which utilizes high temperatures and very high pressures along with various catalysts to produce ammonia (a common inorganic fertilizer) from nitrogen and hydrogen gas. The process uses heavy amounts of electricity and is potentially poisonous to the environment.

  Gaseous emissions of nitrogen can drift with the wind, landing on fields and promoting some species of plants while eliminating others, again reducing the number of species. This happens in farms in the Mississippi River Valley, from which nitrogen emissions drift northeast. According to Schlesinger, this produces a type of acid rain similar to the acid rains of the 1980s and ’90s that resulted primarily from sulfur emissions from power plants mixed with rain to create sulfuric acid. The current problem stems from nitrogen emissions mixed with rain that create nitric acid.

  Duke biologist Richter currently leads a project with Rothamsted to compare soils augmented by inorganic nitrogen to soils augmented with organic manure. High nitrogen from inorganic fertilizers can acidify soils far more than acid rain, and the cumulative effects can be disastrous.

  Back on the campus of Duke University, Richter slid open one of a tall stack of drawers in a chest just outside his office, a proud smile on his face. The drawer was packed with quart-size jars, each filled with soil from the Calhoun Experimental Forest in South Carolina. It was not nearly as large as the Rothamsted sample archive, but it nevertheless represented the careful work of students and researchers from his department and the US Forest Service who are looking for changes in the soil over sixty years, the length of Duke’s study of Calhoun soil. This study is part of a database of long-term soil studies that Richter is trying to establish across the globe.

  Richter showed me a sample from the year 1963, which he held up to the light, brandishing its chestnut brown color. “Nineteen sixty-two was the year Khrushchev and Kennedy were negotiating the atomic test ban treaty to halt atmospheric testing of nuclear weapons, and in those years you see the highest concentration of carbon 14, a signature of radioactivity in the earth’s soil,” said Richter.

  “Bomb carbon,” as he called it, had originally been sited in a series of wine bottles that were hermetically sealed. The grapes used to make the wine had tasted the radioactive air during photosynthesis and held on to it during the winemaking process. According to Richter, it was not directly harmful, but it did give scientists a small “slug of radioactivity” which they could use to determine how soils built and changed organic matter over time.

  NEW SPACES

  A week later, Angelica Pasqualini, a stylish Italian research assistant at Columbia University, took me, her computer, plus two extra sets of shoes in her fashionable bag to the rooftop of Regis High School, an all-boys Catholic school on East Eighty-fourth Street in Manhattan, to show how the school was promoting the use of rooftops for agricultural space. Trays of drought-tolerant plants on top of the building provided natural insulation that reduced heating and air-conditioning costs for
the school. If the city’s one billion square feet of roof space were transformed into green roofs, it would be possible to keep more than ten billion gallons of water out of the city sewer system. “Green roofs help retain storm water runoff,” said Pasqualini. They also provide cheap insulation from the weather and a place for the bees.

  In a corner of the same roof a local beekeeper, Joanne Thomas, checked her beehives to see how her flower breeders were doing. It seems that Manhattan roofs are going green. Her bees stayed healthy on pollen from uptown rooftop blossoms. They also pollinated local plants up and down the street as well as in nearby Central Park.

  On the roof of a gritty industrial building in Brooklyn, a small urban farm called Gotham Greens provides a leafy oasis of green leaf, red leaf, and baby butterhead lettuces, plus Swiss chard, Chinese cabbage, arugula, and basil. Turning the rooftops of New York into mini farms could provide more open earthen space, a commodity that is rapidly diminishing.

  Dickson Despommier, a Columbia University professor and author of The Vertical Farm: Feeding the World in the 21st Century, told me later in his office that abandoned skyscrapers were a viable alternative to open space in New York and other cities throughout the world. This was particularly true in cities in the American Midwest, where urban flight and a struggling economy have left many tall buildings vacant. According to Despommier, these structures could work as hothouses—protecting crops from weather, providing ample window light, and even allowing access to elevators to haul crops up and down for planting and harvesting.

  Grains, fruits, and vegetables are an important part of the future agricultural picture, but what about meat? It takes five times the amount of grain consumed by the entire American population to feed the seven billion domestic livestock animals in the United States. In other words there is a cow, pig, lamb, or goat out there for every American. Only, they eat five times as much as we do. If we ate a little more grain and a little less meat, it would go a long way toward solving our looming food shortage. But grain shortages are not the only problems livestock create.

  In 2006, the United Nations Food and Agricultural Organization report Livestock’s Long Shadow: Environmental Issues and Options highlighted that cattle-rearing generates more greenhouse gases than driving cars. It is also a major source of land and water degradation. If emissions from land use are included, then livestock accounts for 9 percent of CO2 derived from human activities. It also generates 65 percent of human-related nitrous oxide and 37 percent of methane, both of which are much stronger greenhouse gases than CO2. And it accounts for 64 percent of ammonia, which is a heavy contributor to acid rain. Livestock now uses 30 percent of the earth’s entire land surface and is a major cause of deforestation in South America.

  But as countries develop and standards rise, people want to try meat, a symbolic reward for joining the middle class. Yet if, in the process of gaining knowledge and riches, their appetites turn to beef, it could negate the advantage of putting off childbirth in developing countries.

  ENDANGERED SOILS

  Man’s greatest challenge may be finding enough land: we are running out of it. We won’t have enough to grow grain or raise enough cattle if populations don’t stabilize. Ronald Amundson, professor of soil science at the University of California, Berkeley, in agreement with Duke’s Richter, thinks that soils are critical components of the earth’s biosphere, but they are being rapidly transformed by agriculture and urbanization. It’s not a small matter. “The combined human impact on land surfaces during the past few hundred years is as large as that which occurred during the last ice age,” says Amundson. Soil types depend on a combination of climate, geology, and topography to help form them. There are twenty thousand soil types in the US and their natural acreage is now severely depleted. Amundson uses a value of 50 percent reduction to indicate endangered and 90 percent reduction to indicate extinct. “Many types of soil in the United States are currently endangered and a handful extinct,” he wrote to me.

  Some scientists speak of an end to population growth as developing nations send their citizens to school. But many think that our numbers will continue to mushroom longer.

  According to UC Berkeley’s Anthony Barnosky, “With seven billion people alive today, we are devoting 43 percent of earth’s land to agricultural production in one way or another. By the time we hit eight billion we are going to be up to 50 percent of earth’s lands devoted to agriculture. By the time we hit nine billion it will be more like 60 percent of available land. And remember, not all land is created equal. We are already using the best 43 percent. There would be some huge problems.”

  A great number of wars have been fought over food and the space to grow it. The Revolutionary War in the US started with a dispute with the British over tea. Around this time, the British fought with the French over control of sugar-rich Jamaica. The Guerra del Sale (the War of Salt) in the late fifteenth century was fought between Venice and the northern Italian city of Ferrara over the right to tax salt.

  In Jared Diamond’s book Collapse: How Societies Choose to Fail or Succeed, he argues that the genocide and murder of 800,000 Rwandans in 1994 was fueled not solely by ethnic hatred but also by a population too big to feed itself. Their lands had been divided and redivided so many times and grown so small that the remaining plots could no longer feed their owners. We could face similar situations in the future.

  Starvation weakens the body and the spirit. The landscapes we are changing and the species we are killing off will produce ruinous effects in our fight against disease, the next of our growing challenges.

  6

  WARNING SIGN II: OUR BODIES

  AS OUR AGRICULTURAL practices decrease the biodiversity of our plants and animals, one of the unintended consequences is the increased presence of disease. Over the last half century a number of new diseases have developed in our world and we are only beginning to understand our role in their development. The loss of native species decreases the dilution effect that results from having a variety of carriers of disease, some more efficient than others, the less efficient ones decreasing the threat from new diseases. At the other end of the equation, we find that our animal husbandry practices are decreasing our ability to treat disease by creating antibiotic resistant germs.

  A prime example of this threat can be found in the story of Mr. Yu. G. (health authorities used initials to indicate him), a storekeeper who lived in a cotton factory in the town of Nzara in southern Sudan in the late 1970s. He was a quiet man, a recluse. He worked at a desk in the back of a cotton factory with cloth piled all around him. Bats roosted in the ceiling near his desk, which many suspected of making him sick, but no one was able to prove a connection.

  Still, Mr. Yu. G. became internationally famous on July 6, 1976, when he went into shock, blood pouring from all his orifices, and died. He never made it to the hospital. He was the first case ever, the index case, of Ebola Sudan. Mr. Yu. G. shared his office with two other workers who got the disease a few days after his death. They, too, went into shock, began to hemorrhage, and died.

  One of the dead coworkers, P.G., was unfortunately more social than Mr. Yu. G. He had friends and even a few mistresses. The disease spread from him more rapidly. It went through sixteen generations of infection, killing many of the hosts, raging through the town of Nzara and eastward to the town of Maridi, where there was a hospital. It then went through the hospital, jumping from bed to bed, finally going after the medical staff; some got sick, and others grew frightened and fled the hospital. The World Health Organization (WHO) sent a team of investigators, which found that the medical staff’s departure actually turned out to be a blessing, since they had been using dirty needles to inject their patients, unknowingly spreading the disease. Once the practice had stopped, the spread of the disease subsided.

  The death rate for Ebola has been high. Of the 284 people who got Ebola hemorrhagic fever in Sudan in 1976, 151 (53 percent) died. Of the 318 people who got Ebola in that same year in Zaire, 28
0 (88 percent) died. Of the 264 people infected in a more recent outbreak in Zaire in 2007, 187 (71 percent) died. The disease was detected in Uganda and the Democratic Republic of the Congo in 2012. Since the disease travels by blood, it is not as contagious as a common cold, which is spread through the air. It kills so quickly that victims often don’t have a chance to spread it. They’re simply not around long enough to come into bodily contact with many others.

  Recently Ebola has again reared its ugly head and is raging through West Africa. In Kenema, Sierra Leone, the government is trying to quarantine victims in the local hospital. But so many patients and health workers have died there that some victims simply get up and go home, deserting the place because they feel it’s a death trap. In doing so, however, they’re only promoting the spread of the disease and undermining international efforts to contain it.

  Some infected health workers and missionaries have been flown back to their home countries, but are kept in isolation. As we were going to press, the toll was rising into the thousands, the most serious outbreak yet. It’s a small number compared with deaths in Africa from malaria and HIV/AIDS, but it is another reminder of how serious disease can suddenly reappear.

  Some scientists believe that the disease may have been brought to humans from monkey meat. The virus first erupted in a population of research monkeys sent to the city of Marburg, Germany, in 1967, at a place called the Behring Works, which used African green monkeys to produce vaccines. Some of those monkeys turned out to have come from a group of islands on Lake Victoria. Epidemiologists believe that AIDS may have also come from monkeys on these same shores. According to Richard S. Ostfeld, a disease ecologist at the Cary Institute of Ecosystem Studies, about 60 percent of all infectious diseases that affect humans are “zoonotic,” meaning they reside in animals that act as reservoirs for the disease. But this animal association increases to 75 percent for new and emerging human diseases.