As the US prepares to exit the Paris accord, the first actionable global agreement to reduce humanity’s interference with the ecosystem, we may be looking forward to an epoch in which it will be considered normal for human activity to leave permanent marks which scar the world. A related development is visible in the scientific rather than political domain: with the growing acceptance of the term “Anthropocene”, the industrialised human race is on the verge of entering the geological record.
A new epoch in which humanity has physically altered the world, leaving clear signs of its presence and its depredations, was proposed in 2000 by the Nobel Prize-winning atmospheric scientist Paul Jozef Crutzen. He suggested that the world has been qualitatively different since human activities acquired the potential of causing disruptive change in the earth’s constitution. A new epoch had dawned, and the geological horizon at which humans became capable of performing feats like mass species extinction ought to be marked.
It set off a bit of a firestorm in the fraternity of geologists, who like to have clearly defined stratigraphic limits. The study of layers in rocks is the basis for measuring geological time, and its students like to keep the markers nice and neat. The question is whether there is a commonly agreed point where the evidence of world-altering human activity enters the geological record. It remains undecided but the International Union of Geological Sciences is grappling with the question and the word “Anthropocene” (literally, “human now”) is making its presence felt in the literature.
We are now in the Holocene (literally, “wholly now”), the most contemporary period of the development of the earth. Its landscape includes a whole lot that is of human provenance, from a time before the development of material culture. Human and humanoid fossils are our most obvious contribution to the crust of the earth, relics ranging from the discovery of Lucy in the Olduvai Gorge to the finding of the Denisovan culture — on the basis of a couple of teeth, a finger-bone and a toe-bone — in a Russian cave.
Agriculture has left its mark, and generations far in the future will discover carefully demarcated fields after their margins have turned into living rock. Humanity’s migrations are also recorded in pathways that have been trod by so many generations of early humans that they are still visible. In England, “ley lines” become visible when the sun is aslant, marking old trade and pilgrimage routes. Of course, many of Britain’s traditional roads are no longer visible because motorways now roll over them. The earth and tree rings the world over bear the signature of the industrial revolution — soot, ash and effluents.
But these are contributions to the Holocene landscape. The Anthropocene would like to be more dramatic. Its signs will be mass species extinction and the detectable effects of climate change, etched in stone. Dinosaur extinction was the most exciting puzzle thrown up by geology and paleontology, and it still engages researchers, who link it with climate change brought on by volcanic activity or a meteorite striking the earth. Science fiction writers seem to have left it behind, but, back in the day, at least one of them suggested that dinosaurs were wiped out because they had these little guns, which they kept shooting at each other. And then one day, they built a really big gun to settle the issue, and it was curtains.
In the not entirely unlikely event of nuclear holocaust, races which succeed ours may find themselves puzzling over human extinction. By the time it happens, much of human culture may be presumed to be electronic, and its traces would be erased by the electromagnetic pulse accompanying a nuclear explosion. That would leave foxy artefacts like global chains of ruined fast food outlets, to be readily misunderstood as temples with counters behind which, obviously, priests stood to receive bun-shaped offerings from the populace. Since it would be a man-made disaster, nuclear holocaust should certainly be dated to the Anthropocene (does the growing prevalence of the term in the literature evidence of premonition?). While a human-shaped epoch is declared on earth, humanity’s interest in altering the planets for personal use is also old. The idea of “terraforming”, or altering the surface, atmosphere, flora and fauna of planets to human tastes dates back to 1940s science fiction, and it was strongly taken up by scientific bodies including Nasa. While the human race has the scientific and technological power to do this already, it does not have the economic muscle for projects on a planetary scale. But it will, and Mars will one day look a whole lot like Gurgaon. That would be the real horizon of the Anthropocene, when humanity acquires the power to interfere with distant planets, and not only its home world.