Ackerman possesses a talent for the incisive aphorism. Humans, she declares, are “the most successful invasives of all time.” “The Human Age” teems with ­unexpected insights. Who knew that incessant texting prompts a child’s brain map of the thumbs to expand? Who knew that the shift from children playing outside to indoors hunched over screens may be triggering an epidemic of myopia, as studies of young people in Shanghai and Seoul reveal that 95 percent are nearsighted? That fruit flies share 70 percent of human disease genes, including those associated with Alzheimer’s and Parkinson’s? And that some de-extinction proponents envisage reintroducing mammoths to Siberia?

There is, however, a four-ton mastodon in the living room that Ackerman tiptoes around. The 21st-century rise of the Anthropocene as a unitary-species story coincides with a trend toward rising inequality, between the haves and the never-will-haves. In America, we call this the second Gilded Age, but in nations as diverse as China, Ireland, India, Spain and Nigeria, the idea of the human is also fracturing economically. In 2013, the world’s 85 wealthiest individuals had a net worth equal to that of our planet’s 3.5 billion poorest people. Since 1751, a mere 90 corporations, primarily oil and coal ­companies, have generated two-thirds of humanity’s CO2 emissions. That’s a serious concentration of earth-altering power.

When Ackerman uncritically quotes the futurist Ray Kurzweil’s prediction that “by the 2030s we’ll be putting millions of nanobots inside our bodies to augment our immune system, to basically wipe out disease,” this reader was prompted to ask: Pray tell, which “we” would that be? The facts are that in 2014 the number of forcibly displaced people has topped 51 million, the highest figure since World War II. Yes, technological innovation will prove critical in the battle to adapt to the hurtling pace of planetary change, but let’s acknowledge that we’re doing a far better job of encouraging innovation than distributing possibility. In celebrating the culture of innovation, Ackerman focuses on the interplay between technology, ­design and evolution. But what of the decisive role played by forms of governance? In the plutocratic milieu of the 21st century, how do we ensure that innovations aren’t by the few for the few, that they don’t compound the trend toward islands of extreme affluence barricaded against the vulnerable multitudes?

A technology’s emergence is no guarantee that its benefits will trickle down to humanity at large. When men attacked two teenage girls and hanged them from mango trees in India this May, the atrocity drew attention to the fact that the women had to defecate in the forest at night. Two and a half billion humans still lack access to a rudimentary latrine, a venerable technology developed over 3,000 years ago.

Is it uncharitable to want a book that achieves so much to do more? Perhaps. Taken on its own terms, “The Human Age” is a dazzling achievement: immensely readable, lively, polymathic, audacious. But as the Anthropocene becomes a defining paradigm of our time, it matters how we frame the challenges ahead. It’s easy to agree with Ackerman’s assessment that “a warmer world won’t be terrible for everyone, and it’s bound to inspire new technologies and good ­surprises, not just tragedy.” But her assertion deserves a follow-up question: Who is in line for the good surprises, and who is queuing up for tragedy? Hurricane Sandy brought precisely that ­question to the fore. Manhattan? Too valuable to lose. Bangladesh, even Far Rockaway, not so much.