Chapters 6-7 Summary

Kolbert travels to Castello Aragonese, a tiny island off the coast of Italy that has vents in the seafloor bubbling up carbon dioxide (CO₂). Little sea life exists in this area because of the acidity. Scientists research this area because it provides a glimpse of what the future oceans will be like as humans continue to generate increasing levels of CO₂. Oceans are projected to become 150% more acidic by the end of the 21st century. Ocean acidification—called global warming’s “evil twin”—is suspected to have contributed to at least three of the Big Five extinctions.

Kolbert visits One Tree Island in the Great Barrier Reef, off Australia’s coast. Scientists believe coral reefs won’t survive the Anthropocene. Coral reefs are “part animal, part vegetable, and part mineral.” Because reefs are constantly eroded by water movement and eaten by other creatures, they must keep growing. CO₂ erosion, overfishing, agricultural runoff and deforestation are all harmful to coral reefs.

Kolbert joins an expedition to collect water samples with another researcher. She is in awe of the Great Barrier Reef and later notes the diverse sea life among the coral reefs.

Chapters 6-7 Analysis

At the beginning of Chapter 6, Kolbert alludes to the theme of time as a ticking clock. The waters that surround Castello Aragonese provide a glimpse into the future. While the CO₂ surrounding the island appears to be due to natural causes, the same can’t be said for the future of the oceans. Kolbert implies that the oceans are in critical danger. The concept of time is further emphasized as Kolbert reveals the significance of the rate at which humans are adding CO₂ to the atmosphere.

In Chapter 7, Kolbert focuses on the threat to coral reefs. She claims that their disappearance would be devastating to the marine ecosystem because reefs are home to many life-forms, the loss of which would cause a domino effect down the food chain. The possible disappearance of reefs in the next 50 years can be seen as a warning bell for humanity’s survival.

Both reefs and ocean acidity are a mystery to scientists. Reefs have appeared and disappeared throughout the ages. Scientists still don’t understand exactly how and why CO₂ is so destructive to ocean life. Yet, the understanding scientists do have has rapidly evolved in the past two decades. Again, Kolbert emphasizes the paradigm shifts that are defining people’s understanding of extinction.