Half-Earth Gives the “tree of life” at Least a Fighting Chance

Scott Deshefy


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Saved on my old Dell, CD-RWs and, more recently, a flash drive as failsafe is a 660-page tome I’ve been writing for years. Referenced to the point of overkill, it’s a heavily-cited compilation of environmental ethics and moral philosophy, delving into humanity’s destructive bent. I began writing it the first day I retired, over a decade ago. Although back-burnered in recent years, I could easily add another six or seven hundred pages. Surely, as Texas and Mississippi lift mask mandates, I’d be remiss not to include a chapter on stupidity prolonging the pandemic. But, for any realistic chance at publication, a shorter rewrite is probably in the cards. The chapter on global warming and climate change alone is 97 pages. As I rigorously documented tragedies unfolding ─ from islanders made homeless by rising seas to bleaching coral reefs to pikas pushed by heat beyond limits of their mountains to sequoias browned by drought  ─ scientific data filled journals, books and magazines faster than I could assimilate and type.

Last month, a new report by the World Wide Fund for Nature (WWF) warned that unprecedented annihilation of wildlife not only signals our moral decline, but massive natural system failures endangering the biosphere. Scientists conclude destructive human activities, ranging from global trade and urbanization to population growth and disproportionate consumption of natural resources, are primary causes of a 68 percent reduction in mammals, birds, amphibians, reptiles and fish between 1970 and 2016. Earth’s regenerative capacity is also exceeded by species exploitation, such as hunting, pollution in general, and climate change specifically. Wildlife are so ruthlessly destroyed and insect populations so devastated by pesticides that bees are being trucked across States, even flown from Australia, to pollinate California’s fruit orchards. Currently, a third of all land mass is unsustainably developed for agriculture, a major cause of plummeting biodiversity and habitat loss. Meanwhile, grain and soy proteins, which could feed the world’s poor, are increasingly and inefficiently used as cattle fodder. Because only 10% total energy received from one ecological trophic level transfers to the next (i.e., Lindemann’s coefficient), that unnecessary conversion of plant protein to animal flesh for “meat” assures 90 percent waste. Consequently, as Philip Lymbery documents in Farmageddon (2014), farm animals are disappearing from our fields as food production industrializes globally. The resulting mishmash of unidentifiable sources means less is known about our food chain than in the days of Upton Sinclair’s The Jungle. Half of antibiotics used worldwide are given to factory-farmed animals to keep them alive in torturous conditions, contributing to the evolution of potentially deadly, antibiotic-resistant microbes.

WWF conservationists also warn that nonhuman animal habitats, destroyed by human development, are creating what I call “zoonosis zones.” An estimated 70 percent of zoonotic diseases transmitted between other animals and humans, often to and fro, are linked to wildlife coming into contact with humans due to habitat loss. Additionally, more than 85 percent of the world’s wetlands have been lost in the past 300 years, contributing to drying of many major rivers. Unless something is done to reverse this trend, remaining wetlands could be lost by 2100.

Ecosystems are in constant states of flux, both in time and space, and keeping them static, the central fallacy of wildlife management, is impossible even during times of relative equilibrium. In fact, constant change is a vital engine of species diversity. A focus of conservation, therefore, should be maintaining the nature and diversity of ecosystem processes, not keeping populations of so-called “game” animals unnaturally high to manufacture consent for killing them. For much of the past two million years, the planet has experienced oscillating changes of an Ice Age, with alternating periods of cold glaciations alternating with interglacial warming, the Pleistocene epoch. That global warming we’re now experiencing is out-of-synch with that cycle and showing unprecedented temperature increases in such a short space of time (roughly 200 years since the Industrial Revolution) is one of the reasons climate change is undoubtedly caused by human atmospheric discharges. The Pleistocene ended between 12 and 10 thousand years ago, giving way to the Holocene epoch which, because of devastating impacts on the environment caused by human activity, has recently been dubbed the Anthropocene. With each transition between glacial and interglacial temperature changes, the Earth’s plant communities changed and migrated dramatically as did the animal species depending on them for survival. Pleistocene pulses created aforementioned ecosystem changes which, in turn, resulted in times of pronounced origins and extinctions of species.

When extinctions happened, there was a curious imbalance, however. Large species, especially big mammals, were most vulnerable. In 1876, Alfred Russel Wallace, who independently co-developed the theory of evolution by natural selection with Charles Darwin, believed causes for these extinctions were massive disruptions in plant communities from sustained global temperature increases. The changes spelled disaster for woolly mammoths, mastodons, Deinotherium, saber-toothed cats and Diprotodon, the largest known marsupial. But in time, Wallace changed his mind. In 1911, he wrote assuredly that “the extinction of so many large Mammalia is due to man’s agency.” When Wallace gave support to the idea that human hunting was, and remains, ecologically disruptive, resulting in mass slaughter of giant mammals, some found it difficult to accept, even as once-teeming passenger pigeon and bison populations were “harvested,” that is, slaughtered for sport. Now, scholars accept as undeniable that Homo sapiens evolution has meant disaster for the rest of the natural world. Ungainly, sensorily diminished, and short on survival smarts, we humans pose the greatest threat for mass extinctions this planet’s seen since the Chicxulub asteroid hit 66 million years ago. We’re just one of tens of millions of living species, but act like insatiable spoilers, unwilling to share the Earth’s sustenance. Out of sheer ignorance or to line people’s pockets, if we continue to choose paths of destruction, the biosphere will descend irreversibly into this Anthropocene end game in which the planet exists only for ourselves, even failing to sustain us. Biologists agree that, because of human activity, extinction rates are catastrophically high. Species are disappearing between 1,000 and 10,000 times the rate before Homo sapiens first began to exert significant, detrimental pressures on the environment.

In The Future of Life (2002), biologist-naturalist extraordinaire Edward O. Wilson first elaborated on his idea to save the biosphere, a concept he more fully developed in Half-Earth fourteen years later. Despite their parlous condition today, Wilson concludes Earth’s ecosystems can be saved by limiting humanity’s use of the planet to no more than half its terrestrial surface and devoting the remaining half entirely to nonhuman life. This is no modest proposal, but a necessary one. The share of the planet, protected and allotted to the rest of nature, must be left entirely undeveloped and situated where shrinking hotspots of high species diversity can be expanded. Today only about 10 percent of the land surface is protected on paper. Even if stringently preserved as sanctuary, this amount is nowhere near enough to save more than a modest fraction of existing wildlife. Large numbers of floral and animal species are already left with populations too small to persist unless we act swiftly and decisively. Some, like the magnificent Sumatran rhino are already doomed to join the dodo, ground sloth, Quagga, European cave lion, Thylacine, and great Auk. Also, more than 15 percent of flowering plants, a majority of animal fauna and millions of microorganisms (the “deep biosphere”) remain undiscovered, unnamed and of unknown status. E.O. Wilson’s “half Earth” solution thusly considers not only large creatures and celebrated species of plants but also vast arrays of invertebrates and microorganisms that form the biosphere’s foundation and conditions supportive of life, including our own.

It’s time we stopped worrying about privileged plunderers, estranged royalty and prodigal celebrities. It’s time to focus on the important and buckle down to critical jobs at hand. Half-Earth gives the “tree of life” at least a fighting chance.

Scott Deshefy is a biologist and ecologist and two-time Green Party congressional candidate.