Geology’s human footprint is enough to spur rage

Once again science has presented evidence that a new geological epoch is here. This human footprint is all our own work.

LONDON, 21 October, 2020 − The human footprint has left its mark on Earth, in every sense. The United States alone is scarred by 500,000 abandoned mines and quarries.

Right now, worldwide, there are more than 500,000 active quarries and pits, employing 4 million people, excavating the sand and gravel needed for new roads, new homes and new megacities.

Humans have not simply pitted the face of the Earth, they have paved it. In 1904, beyond the cities, the US had just 225 km of sealed highway. Now it has 4.3m km of asphalt or concrete roadway, consuming more than 20 billion tonnes of sand and gravel.

By comparison, the Great Wall of China, the biggest and most enduring construction in early human history, contains just 0.4bn tonnes of stone.

Humans have changed the face of the waters. In 1950, trawlers, long-liners and purse seiners fished just 1% of the high seas beyond territorial waters. No fish species of any kind was considered over-exploited or depleted.

Extinction threat widens

Less than one human lifetime on, fishing fleets roam 63% of the high seas and 87% of fish species are exploited, over-exploited or in a state of collapse. Meanwhile somewhere between 5m and almost 13 million tons of discarded plastics flow each year into the sea.

Humans and human livestock now far outweigh all other mammalian life. At least 96% of the mass of all mammals is represented by humans and their domesticated animals. Domestic poultry makes up 70% of the mass of all living birds. The natural world is now endangered, with a million species at risk of extinction.

And humans have left an almost indelible radiant signature over the entire global surface: between 1950 and 1980, nations detonated more than 500 thermonuclear weapons to smear the air and surface of the planet with radioactive materials: one of these, plutonium-239, will be detectable for the next 100,000 years.

The catalogue of planetary devastation that is the human footprint is assembled in a new study by US and European scientists in the journal Nature Communications: Earth and Environment. It is part of a fresh attempt to settle a seemingly academic question of geological bureaucracy, the naming of ages.

“We humans collectively got ourselves into this mess, we need to work together to reverse these environmental trends and dig ourselves out of it”

The 11,000-year interval since the end of the last Ice Age and the dawn of agriculture, metal smelting, and the first cities, cultures and empires is still formally identified as the Holocene. The latest study of the human legacy is just another salvo in the campaign to announce and confirm the launch of an entirely new epoch, to be called the Anthropocene.

In fact, environmental campaigners, biologists and geophysicists have for years been informally calling the last six or seven decades the Anthropocene. But the authority with the last word on internationally-agreed geological labels − the International Commission on Stratigraphy − has yet to confirm the launch of the new geological epoch.

To help confirm the case for change, researchers have once again assembled the evidence and identified at least 16 ways in which humans have dramatically altered the planet since 1950, and the beginning of what is sometimes called The Great Acceleration.

For instance, humans have doubled the quantity of fixed nitrogen in the biosphere, created an alarming hole in the stratospheric ozone layer, released enough gases to raise the planetary temperature and precipitate global climate change, fashioned or forged perhaps 180,000 kinds of mineral (by comparison, only about 5,300 occur naturally) and − with dams, drains, wells, irrigation, and hydraulic engineering − effectively replumbed the world’s river systems.

Ineradicable scar

By forging metals and building structures, humans have become the greatest earth-moving force on the planet, and left a mark that will endure for aeons.

Altogether, humans have altered the world’s rivers, lakes, coastlines, vegetation, soils, chemistry and climate. The study makes grim reading.

“This is the first time that humans have documented humanity’s geological footprint on such a comprehensive scale in a single publication,” said Jaia Syvitski, of the University of Colorado, Boulder, who led the research team that assembled the evidence.

“We humans collectively got ourselves into this mess, we need to work together to reverse these environmental trends and dig ourselves out of it.

“Society shouldn’t feel complacent. Few people who read the manuscript should come away without emotions bubbling up, like rage, grief and even fear.” − Climate News Network