Perhaps you've noticed, amid the hot invective and dry mockery of daily events in your social media feeds, reports of the glaciers melting at each pole.

Arctic ice cover reached record lows this summer and autumn. In Antarctica, we saw the continuing enlargement of an already massive crack in the region's fourth-largest ice sheet, threatening its continued stability. Last year was the hottest ever recorded, surpassing the previous record in 2015, which had in turn exceeded that of the previous hottest year ever recorded, 2014.

Just as the world seemed poised to embark on a collective effort to wean itself off dependency on fossil fuels, its leading power elected as president a man who has claimed that global warming is a conspiracy invented by the Chinese and who went on to select as his secretary of state the chairman of ExxonMobil. The choices they make will shape the future of all planetary life.

Our inability to connect the day's ephemera with the geological time scale has summoned a striking neologism: the Anthropocene, or the Age of Man. Its meteoric rise is a case study in the stubbornness of the problem that the term was designed to master.

Coined by atmospheric scientist Paul Crutzen around 2000, it expressed his intuition that humanity had become tantamount to the great forces of nature and that our activities were shaping the state of the systems that regulate the conditions of life. He believed the human-induced impact on the world had become so great that we had pushed the planet into a whole new stage of the geological time scale, leaving behind the Holocene epoch, which began 10,000 to 12,000 years ago.

Dr Crutzen and a group of like-minded scientists set about grounding his improvised conceit with empirical findings drawn from various earth sciences. We have dammed half of the world's large rivers, subdued nearly 40 per cent of its land mass for agricultural use, invented plastics, smelted metals and spread other novel particles of our own devising around the globe. According to some estimates, 95 per cent of the vertebrate biomass on land consists of ourselves, our pets and livestock bred to our specifications and raised mostly in enormous industrialised monocultures.

The concept of the Anthropocene is that, in the distant future, these changes will be legible in the record preserved in the earth - in ice cores, in sediment, in fossils, everywhere.

Last August, a working group within the International Commission on Stratigraphy issued a recommendation that the wider body formally designate the end of the Holocene epoch and declare the Anthropocene a reality. Some wondered if the scientists were doing science at all or making a political statement. (After all, geological epochs are usually named millions of years after they end.) This leaves the effort to fix the meaning of the Anthropocene in stratigraphical terms inconclusive.

It also leaves the term feeling rather irrelevant. It has slipped free of its original intentions, diffusing rapidly throughout academia and slowly trickling into the consciousness of the mainstream press. Part of the Anthropocene's appeal was the sound of the word itself: portentous, stately, vaguely Latinate, imbued with a dark majesty. Another part of its appeal was its capaciousness - large enough to swallow the whole planet and everything living on it.

Dr Crutzen wished to capture the imagination and frame the world in a word that would create urgency around the issue of climate change and other slow-building dangers accruing to the earth. But the risk was always that the word would capture the imagination all too well and become more like a summons to further heroic exertions to remake the world in our own image.

In naturalist Diane Ackerman's 2014 book, The Human Age: The World Shaped By Us, she declares herself "enormously hopeful" at the start of the Anthropocene. She goes on to chronicle, in a mood of excited ambivalence, the good and the bad: "a scary mass extinction of animals" and "alarming signs of climate change", but also a number of promising "revolutions" in sustainability, manufacturing, biomimicry and nanotechnology.

Novelist Roy Scranton, in his short 2015 polemic, Learning To Die In The Anthropocene, calls on us to abandon false hope in the "toxic, cannibalistic and self-destructive" system of carbon-based capitalism, and to "learn to die not as individuals, but as a civilisation".

And law professor Jedediah Purdy, in his 2015 tract, After Nature: A Politics For The Anthropocene, contrives to see opportunity in the crisis. Although he acknowledges that humanity currently lacks the political institutions to act collectively on a global scale, he allows himself the hope that a new politics will arise that will be "democratic in the double sense of thoroughly politicising nature's future and recognising the imperative of political equality among the people who will together create that future".

Whatever else our posterity might come to lack, it will not suffer from a dearth of grand invective or sonorous incantation.

While humanists have bent the Anthropocene to serve their own purposes, technologists have turned what began as a call for radical austerity into a renewed push for significant technological advances.

Israeli writer and historian Yuval Harari's book, Homo Deus, published this month in the United States, makes the case that the 21st century will see an effort "to upgrade humans into gods" who will take over biological evolution, replacing chance with intelligent design oriented around our desires. By merging with our technologies, we could be released from the biases that plague our cognition, free to exercise the meticulous planning and invention required to save the planet from ourselves.

Dr Harari's book is the closest thing we have to a single-volume account of the techno-futurist vision favoured by our Silicon Valley elites - his work has been cited by Microsoft co-founder Bill Gates and Facebook chief Mark Zuckerberg - and it is as uneasily poised at the conjuncture of standard history and science fiction, of sober analysis and mad prophecy, of nightmare and utopia, as we ourselves have come to be.

The book's ruthless appropriation of the Anthropocene will almost certainly be regarded as an obscenity by those who first rallied around it, a celebration of the very hubris that brought us to the brink of destruction in the first place.

Unwinding the damage we've done to the earth now represents a challenge so enormous that it forces us to dream about fantastical powers, to set about creating them and in the process either find our salvation or hasten our demise.

Right around the time we confirmed that the sixth great extinction had already begun, scientists discovered Crispr - bacterial DNA that can be manipulated to edit genes and perhaps bring back extinct species or invent new forms of biological life.

Harvard biologist George Church is leading an attempt to transform an elephant's genome into that of a woolly mammoth, one of many "de-extinction" projects. One purpose is to show that such feats are possible, to demonstrate that humanity can reverse a sentence as final as extinction.

But the ultimate goal, Dr Church has said, is to release the beasts into the permafrost, which they can save by trampling the shrubbery that would otherwise break it up in a warming climate - helping to preserve, at least for a while, the conditions that gave rise to humanity in the first place.

NYT MAGAZINE

•The writer has written for Harper's Magazine, New York Magazine and the New York Times Magazine, and is at work on his first book.