52 pages • 1 hour read
Alan WeismanThe World Without Us
Nonfiction | Book | Adult | Published in 2007A modern alternative to SparkNotes and CliffsNotes, SuperSummary offers high-quality Study Guides with detailed chapter summaries and analysis of major themes, characters, and more.
Part 1, Chapters 4-6Chapter Summaries & Analyses
Part 1, Chapter 4 Summary: “The World Just Before Us”
New York emerged from the last ice age 11,000 years ago. Based on the historical pattern, another ice age should be imminent as of the book’s writing. However, the massive amounts of carbon dioxide humans have added to Earth’s atmosphere through industrialization have delayed its onset by at least 15,000 years. Once humans are gone, it will take at least 100,000 years for the geologic cycle to reduce atmospheric carbon dioxide to prehuman levels.
Weisman changes topics with a question: “[I]f we disappeared, would—or could—we, or something equally complicated, happen again?” (42). By way of an answer, Weisman briefly outlines the evolution of humans in the Great African Rift Valley: Chimpanzee-like apes driven by food scarcity venture out of the jungle onto the savanna, evolving into bipedal hominids and then Homo sapiens, who spread out of Africa through Asia, inventing agriculture in the Middle East and finally crossing an interglacial land bridge to Alaska and the Americas. In a posthuman Africa, Weisman wonders whether chimpanzees or bonobos—humans’ closest genetic relatives—might follow a similar evolutionary path again, developing humanlike intelligence. Expanding forests would most likely provide ample habitat for them to thrive without coming down out of the trees, at least until the next ice age reshaped the planet again.
Part 1, Chapter 5 Summary: “The Lost Menagerie”
This chapter explores a scientific mystery: the fate of the elephants, rhinoceroses, mammoths, gigantic ground sloths, and other terrestrial megafauna that inhabited the Americas long ago. After humans first crossed into North America, about 13,000 years ago, some 40 species of large land mammals went extinct within a few thousand years. One theory, known as the “Blitzkrieg” or “over-kill,” is that the bigger-brained humans, with their axes and flint-tipped spears, quickly wiped out the unsuspecting animals through hunting. Zoologist Paul Martin developed this theory in part based on the presence of flint projectile tips in the skeletons of mammoths and other large mammals. Skeptics of the theory question whether a relatively small number of hunter-gatherers could kill millions of animals so quickly. Alternative hypotheses invoke sudden climate change (“over-chill”) or humans’ introduction of new disease pathogens to which native animal populations had no immunity (“over-ill”).
Part 1, Chapter 6 Summary: “The African Paradox”
Unlike the Americas, Europe, Asia, and Australia, Africa has never experienced a major wildlife extinction and thus can be seen as a “continent-sized museum” of large mammals. This is the “paradox” of the chapter’s title: Given that humans have lived in Africa longer than anywhere else, one might expect all of Africa’s megafauna to have been killed off as well. The difference is that in Africa the animals evolved alongside humans and therefore had time to develop adaptations for coping with human hunting. The American animals, in contrast, did not have the chance to adapt to the new threat.
African wildlife therefore offers a glimpse into a prehuman (and potentially posthuman) world. Weisman wonders whether Africa’s megafauna might in the absence of humanity spread to other continents and eventually replace or come to resemble those regions’ lost megafauna. Paul Martin, introduced in the previous chapter, has in fact proposed introducing African elephants in the American southwest to clear mesquite brush on public lands. In the absence of humans, Weisman concludes, “American forests represent vast niches awaiting any herbivore big enough to extract their woody nutrients” (83).
However, population growth and conversion of wildlands for farming and grazing are beginning to seriously threaten the survival of megafauna even in Africa. In Kenya, the landscape was shaped over millennia by the competition between wild elephants and nomadic Maasai cattle herders, whose complementary grazing pressure maintained a productive mosaic landscape of grassy savannas and woodlands. After their cattle grazed down the grasses, the herders would move on to new pastures while the grazed savanna would be invaded by woody shrubs, which would then be eaten by elephants, clearing the way for grass to regrow and the cattle to return. Today, with more and more wildlands being developed, the Maasai herders have been compelled to become more sedentary, and the remaining savanna has become overgrazed. Elephants and other wildlife are increasingly confined within the borders of national parks, which consequently lose their trees. As cultivated and developed land encroaches ever closer to park boundaries, wild animals increasingly invade those lands and destroy crops.
At one national park in mountainous central Kenya, a 200-kilometer electrified fence has been installed to keep wildlife and people away from each other and to protect the watershed from further deforestation. In the 1990s, people began cultivating flowers for export to Europe, and as the enterprise grew explosively, flower factories overpumped the water table and polluted it with fertilizers and pesticides. If humans disappeared, the roses and carnations would die without tending, and wild animals would promptly trample the deactivated fence and spread across the landscape. Domesticated cattle would be predated, their grazing role taken over by expanding populations of wildebeest, and elephants would be restored as “the undisputed keystone species in a patchwork mosaic African landscape” (82). The invasive exotic eucalyptus tree, originally introduced from Australia by British colonizers, would spread too, colonizing deserted fields and outpacing slower-growing native trees. However, native flora would fare better overall in Africa than on other continents because the continued presence of so many wild grazers and browsers has largely limited the spread of exotic plants.
Noting certain similarities between baboons and humans, including brain size and adaptation to savanna existence, Weisman wonders whether baboons might evolve to fill humanity’s niche: “Has their cranial capacity lay suppressed during the Holocene because we got the jump on them, being first out of the trees?” (87). As with his other speculative questions, Weisman does not offer an explicit answer.
Part 1, Chapters 4-6 Analysis
Chapters 4-6 center on the origins of the human species and its earliest impacts on other species. Chapter 4 poses the question of whether the evolution of humans was “inevitable” and the related question of whether a similarly intelligent species could have evolved if modern humans’ ancestors had died out or would evolve after humans’ disappearance. Weisman’s answers are characteristically oblique and somewhat contradictory. On the one hand, the emergence of Homo sapiens was not inevitable but the chance result of evolutionary adaptation to environmental change: Seven million years ago, expanding glaciers caused an extreme drought in the Great African Rift Valley, which fragmented the vast forest. This put pressure on humans’ ape ancestors to venture into the savanna and become bipedal. On the other hand, Nature Is Flux and evolution itself is inevitable, even if the specific directions in which it unfolds are not. Regardless of the fate of those first hominids, chimpanzees as a species would still have possessed—and would continue to possess in a posthuman future—the genetic potential to evolve larger brains. Weisman stresses their intelligence, writing, “A chimpanzee in his element, regarding you coolly from a branch of an mbula fruit tree, expresses no sense of inferiority in the presence of a superior primate” (50). The implication is that over the vast expanse of geologic time, it is more likely than not that the right conditions would emerge to drive chimpanzees out of the forest and start the evolutionary ball rolling again. He also notes that chimps are excellent hunters, with an observed 80% success rate, and that they are aggressive and territorial, harkening to the theme of Humans as Innately Destructive; perhaps anything that filled humans’ evolutionary niche would behave similarly, Weisman suggests.
Chapter 5 addresses the mass extinction of large terrestrial mammals in the Americas during the Pleistocene epoch, offering one answer to the question first posed in Chapter 4: “Had humans never evolved, how might the planet have fared?” (42). Drawing on the research of paleoecologist Paul Martin and colleagues, Weisman concludes that if early humans had never crossed the land bridge from Asia to Alaska, the Americas might still be teeming with elephants, mammoths, giant sloths, and other megafauna. The chapter’s final scene takes place at Tucson’s International Wildlife Museum, where Martin is giving a talk on the Pleistocene extinction in the mock trophy room of a millionaire big-game hunter whose collection the museum houses. Surrounded by the taxidermized heads of hundreds of bears, elephants, white rhinos, and other animals from five continents, Martin says, “I can’t imagine a more appropriate setting to describe what amounts to genocide,” adding that, within his own lifetime, genocides from the Nazi Holocaust to Darfur “are proof of what our species is capable of” (66). Weisman echoes Martin’s disapproving tone, referring pejoratively to the hunter’s “obsession” with big game and macabrely noting the stuffed heads’ glass eyes. Weisman ends the chapter by tacitly endorsing Martin’s exhortation to learn the lessons of history and prevent another mass extinction on par with or greater than the one that killed American megafauna. The problem is not that humans are predators, Weisman writes, but that we have not evolved to set limits on ourself: “[Eventually] something we never intended to harm is fatally deprived of something it needs” (67). This emotive language aims to prick the reader’s conscience and elicit an emotional engagement with the reality of the Anthropocene extinction.
Chapter 6 guides the reader from Pleistocene through 21st-century East Africa, focusing on how current population growth is driving conversion of wildlands with consequent reduction of biodiversity. As with the previous chapter’s invocation of genocide, Weisman suggests a connection between violence against nature and violence against fellow humans. He compares highly endangered black rhinos evading hunters in the remote Aberdares rain forest today to the Kikuyu guerrillas who hid in the same forest during the 1953 Mau Mau Rebellion against the British colonizers who had conquered their land. He also contends that the age-old ecological balance between African pastoralists and wildlife “first began to shift when humans became prey themselves—or rather commodities” (76). Arab enslavers marching caravans of captured African villagers from the central plains to the port at Mombasa harvested elephants for ivory along the way, and as the price of ivory rose, the enslaved Africans worked as ivory porters. The statement that “thousands of elephants and humans perished along the ivory-slave route” implies a moral equivalency between slavery and the slaughter of megafauna (77), aiming to intensify the reader’s emotional response to the latter.
