The Sixth Extinction: An Unnatural History is a loosely connected compilation of essays and field notes written by Elizabeth Kolbert, a staff writer of The New Yorker. Each of the thirteen chapters tracks the extinction or near extinction of a species, and this smattering of evidence wanders into the assumption that mass extinction on planet Earth is again underway for the sixth time.
If you are thinking that climate change (aka global warming) will trigger the sixth extinction, you will have to read to page 102 to find the first mention of this threat. Later, in Chapter VIII, Kolbert carves out space to pad a declaration by Chris Thomas, a biologist at the University of York in England: "Climate change alone 'is unlikely to generate a mass extinction as large as one of the Big Five.'" He estimates that the extinction would extend to "around 10 or more percent of species."
As for the deadly results of pathogens, they are examined cursorily in just three pages. There is apparently no evidence that pathogens will threaten higher life forms, including Homo sapiens, otherwise known as the human organism.
This leaves acidification of the oceans as the likely trigger for mass extinction. Kolbert probes this topic in Chapter VI, The Sea Around Us, by citing a field trip she had at Castello Aragonese, a tiny island west of Naples, Italy. Here she makes this announcement: "Carbon dioxide has many interesting properties, one of which is that it dissolves in water to form an acid." (It will be helpful to remember that burning fossil fuels produces CO2.) Kolbert's guide is marine biologist Jason Hall-Spencer. Before the chapter closes, Kolbert offers this lament from Hall-Spencer: "Unfortunately, the biggest tipping point, the one at which the ecosystem [of the waters off the coast of Italy] starts to crash, is mean pH 7.8, which is what we're expecting to happen by 2100."
After Kolbert dropped this bombshell that life in the waters of the Mediterranean will crash by the end of this century—that's 82 years from now!—you'd think she would examine this part of the world with further scientific scrutiny but no, this didn't happen. Hey, if the Mediterranean is about to crash, then the Atlantic Ocean would soon follow, and you can kiss the Pacific goodbye. Hello, are there any marine biologists who understand the domino theory?
Kolbert must leave the dying Mediterranean because she must resume her travelogue. In the next chapter, she visits a speck of an island off the coast of Australia to study the effects of acidification on the reef that surrounds the island. In the chapter after that, she visits a mountainous region where the trees have been "moving upslope," which is to say, the higher reaches of the mountain, which had been too cold for the trees to grow, had warmed up and thus the seeds from the trees have taken root at higher elevations.
This jumble in presenting The Sixth Extinction is maddening. The subject never develops except by implication. Apparently the editors at Henry Holt and Company thought the author's travelogue would somehow validate the title of the book. The title, as terrific as it is, trolls with unbaited hooks.
Dear Elizabeth Kolbert and editors, you don't inform the reader that the Mediterranean is dying, then move on to explore a failing reef at an island, which "is less than 750 feet long and 500 feet wide." Wake up! The state of life on Earth has caught up to the science fiction that has shown how easy it is to wipe out life forms on the planet. Once the Mediterranean fails, it's all over!
The year 2100 may be too soon to write the obituary for life on this planet, but given the lack of stewardship among humankind for Earth and her countless families, the extinction of nearly all life appears certain.