The Sixth Extinction Chapter 7 - Elyonni Tordesillas

     Kolbert begins this chapter by talking about a place called One Tree Island, located near the Great Barrier Reef, in Australia. On the island, there’s a small research station affiliated with the University of Sydney. In the station, teams of scientists from around the world study the chemical composition of the nearby coral reefs. During her time on One Tree Island, Kolbert meets a scientist named Ken Caldeira. Caldeira’s research focuses on the impact of carbon dioxide on ocean pH, or acidity, but he has also studied the chemical composition of forests and the recent changes in global temperature. The first evidence that carbon dioxide could destroy coral reefs came in the late 1980s with the Biosphere Project in Arizona, which was a huge, glass structure designed to be a self-sustaining ecosystem. The project concluded that the high carbon dioxide levels eroded the composition of coral inside the Biosphere, challenging the common notion that coral reefs are immune to changes in carbon dioxide levels. In recent years, scientific studies have shown that coral reefs erode significantly when carbon dioxide levels rise in the surrounding water, meaning that, at the current rate of carbon dioxide levels, reefs are expected to “dissolve” in the next half-century. Coral reefs have come and gone throughout the planet’s history. In the Triassic Era, for example, nearly all the world’s reefs dissolved. It’s likely that coral reefs will disappear faster than they’ve disappeared at any point in the past, since they face the combined threats of carbon dioxide emissions, overfishing, and pollution. The rising temperature of ocean water also poses a significant threat to coral reefs. The disintegration of coral reefs isn’t unprecedented in planetary history, and rising water temperatures won’t destroy all life in the oceans. Some algae species will be able to thrive. Nevertheless, the destruction of the coral reefs due to human activity is a process that Kolbert presents as tragic. The reefs are beautiful and complex and they stand, symbolically, for the earth as a whole.