The title and subtitle of this book should be reversed. The book is about the earth in a cosmic context. What we take for granted – the Earth, our home as we know it now – has a history of fragility (e.g., in just the last ice age, there have been at least 20 ice cycles). As serious as these disruptions have been, Gaia-like feedback mechanisms, for the most part, pull the Earth back into balance. But at least on two occasions (“late Precambrian Snowball Earth…an ultra-ice age when the oceans may have frozen over” and “the Permian-Triassic oxygen crisis, which led to the most severe mass extinction event in Earth’s history and in which some 90 percent of all species died out….”) the damage was severe enough that it resulted in “profound reorganizations of the biosphere.” In addition to the potential for meteor strikes, future threats include the decrease in the magnetic field’s intensity (there’s been a 10% decline in the last 150 years “which could leave the Earth more vulnerable to cosmic irradiation for a few centuries”). We know about ecosystem balance – the flow of energy happens in response to inequality - and we might comfort ourselves with that, but then the author says that “ecosystems are dismantled, reassembled, or fabricated without serious consequences for the integrity of the whole. Arms races in the geologic record always end, but never with victors. Instead, an external referee – a meteorite, an ice age, a methane belch – abruptly changes the criteria for fitness, and all the elaborate armaments and defenses so assiduously stockpiled become as useless as a credit card in the wilderness.”
As has been said by many others, the author writes that humans have disrupted the ecosystem balance, with harmful or unknown consequences for life, including our own. What concerns the author most is the impact we are having on global climate, and we already see troubling signals that are roughly parallel to the Permian extinction due to a global methane belch. She advocates a Taoist-like approach where we constrain our outsized impacts, to live within limits. Looking at all of this, though, one senses doom. There’s a fatal flaw in the human species. Negative consequences to our actions lie years and centuries down the road. We are a here and now species. Even if we can see the effects of human impacts, we still don’t care enough to change our behavior. We vaunt our great minds, but we are, really, less than squirrels who plan for the winter.
The author is a geologist who can write. This is no jargon- or formula-filled book. The concerns, the warnings – from reading the rocks – are softly but obviously stated. This is not an in-your-face advocacy book. She says what needs to be said in the way it needs to be said. It’s a sophisticated summary of what she, an expert, knows about the impacts of humans who ignore the dead-end consequences of living outside their bounds.