The Future of Life

At the outset of Chapter 1, Wilson notes that life exists on every surface of the earth, from the highest mountain to the deepest point in the ocean. One of the most extreme places life can be found is in the McMurdo Dry Valleys of Antarctica, “where soils are the coldest, driest and most nutritionally deficient in the world” (3). Even in this inhospitable place—the landscape of which resembles that of Mars—there is a wide variety of microscopic life, such as bacteria, single-celled algae, and microscopic invertebrates, all fueled by the summer flow of meltwater.

These animals, Wilson says, are called extremophiles—species adapted to life at the outer extremes of survivable conditions. The most highly adapted organisms among extremophiles are microbes, including bacteria and a related set of organisms, archaea. Some bacteria can live on the walls of volcanic hydrothermal vents of the ocean floor, where they thrive in temperatures of 221 degrees Fahrenheit. Others survive in hot sulfur springs, in the mud from the bottom of the Marianas Trench, or even when exposed to radiation a thousand times what it would take to kill a human being.

Studying how life is distributed, Wilson says, we can learn patterns about how life proliferates: first, that bacteria and archaea exist everywhere there is life; second, that if there is any available space, invertebrates will prey on these microbes; third, that with greater space, larger animals inhabit that space; and finally, that the greatest diversity of life (in terms of number of species) occurs in areas with the most solar energy, ice-free terrain, varied terrain, and climactic stability, such as equatorial rainforests. This biodiversity is then organized in three levels: ecosystems, species, and genes.

Species is the unit by which many biologists measure biodiversity, as species can be relatively readily counted—between 1.5 and 1.8 million have been discovered and named, but Wilson notes the true number of species on Earth may be as high as 100 million. Particularly abundant—and underexplored—are species of microbes and fungi, of which “millions more may await discovery” (15). Wilson closes the chapter by noting what he considers a tragedy for human beings: that life forms are disappearing before we even fully understand that they exist. 

Wilson starts Chapter 2 by describing a tension in the 20th century. Even as the 20th century saw technological advances, artistic innovations, and the spread of human rights and democracy, it was also a time of world wars, genocide, and widespread environmental destruction: “If Earth’s ability to support our growth is finite—and it is—we were mostly too busy to notice” (22).

In the relative calm of the 21st century, Wilson says, it is time to ask how humans can live sustainably on the planet, including by addressing human population growth. To explore this issue, Wilson first imagines a dialogue between an economist and an ecologist, both of whom want to preserve life, but who conceive of that goal in very different ways. The core of that difference, Wilson writes, is the question of whether infinite growth is possible on a finite planet. From here, Wilson turns to examining the phenomenon of population growth and its impact on the environment, referring to “the bottleneck through which humanity and the rest of life are now passing” due to the exponential growth of the world’s population (28).

In mid-October 1999, the human population reached six billion. Since then, it’s grown by about 200,000 people a day, a growth rate of 1.4 percent. A birthrate of 2.1 ensures a stable population that neither grows nor shrinks, but anything above this—even in those regions where the birth rate has dropped—ensures an exponentially growing population. Where birthrate has declined, Wilson notes this drop can be attributed to globalization, urbanization, and women’s empowerment. This potentially universal trend towards smaller families may halt and then reverse population growth, but not before the population likely reaches a level somewhere between nine and 10 billion.

Whether or not the planet can support this many people depends on factors that include how resources are distributed and what quality of life people achieve; for instance, Wilson says, the planet can feed 10 billion people with an East Indian diet featuring mostly grains, but only 2.5 billion Americans, who consume more meat and poultry. In other words, Wilson says, the earth has a fixed capacity to sustain life.

To further explore the consequences of these constraints, Wilson turns to the People’s Republic of China. Much of China’s population is concentrated in the basins of the Yellow and Yangtze rivers—the only arable land available. While technological innovations allowed China to nonetheless become one of the largest grain producers in the world, Wilson notes that its population will soon consume more than the country can produce, and the capacity of other grain producers to pick up the slack is limited. What’s more, the scale of Chinese demand means that in purchasing from other producers, China could drive up the price of grain for everyone. In the meantime, China’s growth has had serious consequences for the environment: Of China’s 50,000 kilometers of rivers, 80 percent no longer sustain fish.

Wilson closes the chapter by noting that China provides a model to the rest of the world, not only because it stands to have such an impact on the rest of the planet, but also because it’s an example of where the rest of the planet is headed. Given this potential future, Wilson says, the only way to ensure the survival of life is through the development of a “universal environmental ethic” (41).