Extinctions: From Dinosaurs to You

This unnerving study from science writer Frankel (Land and Wine) contextualizes the current climate crisis by comparing it to the extinction of the dinosaurs 66 million years ago. The asteroid that caused that mass die-out created environmental challenges similar in some respects to the present, Frankel contends, noting that the soot driven into the sky from impact acidified the oceans and changed the planet’s climate (cooling it, in that case, by blocking out the sun) faster than many creatures could adapt. Discussing why many scientists resisted the asteroid theory when it was first proposed in 1980, Frankel explains that “ruling opinion among geologists” held that “Earth processes were necessarily slow and progressive,” a bias he suggests can still be seen in “scientists and opinion makers” who downplay humanity’s ability to fundamentally alter the environment in a short time span. The illuminating research shows that humans were a major ecological influence long before the Industrial Revolution, explaining that homo sapiens likely caused the planet to cool 12,000 years ago by killing off megafauna whose methane-rich flatulence helped trap atmospheric heat. Amid his sometimes technical discussions of the scientific literature, Frankel nonetheless makes sure to drive home the alarming bottom line, as when he summarizes an academic article that estimated if current trends keep pace, 75 percent of mammals will go extinct in 330 years. This is an urgent wake-up call. Photos. (May)