Humans make up less than 0.01% of all living things on Earth, but our impact is projected to overtake all life by the end of 2020, scientists estimate. In a new study published in the journal Nature, scientists say 2020 marks the year that human-made objects, such as asphalt, steel, and concrete, will outweigh all biomass on Earth, such as plants and animals.
In 1900, the mass of human-made material was equal to only 3% of total biomass on Earth. This changed after the post-World War II construction boom of the 1950s. Since then, the mass of human-made material has doubled every 20 years, now roughly weighing one teraton. What’s more, humans have produced roughly 30 gigatons of material every year for the past five years, and scientists say if this trend continues, the weight of human-made objects will become triple that of living biomass by 2040.
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As humans continue to exponentially increase our production of buildings, roads, and other things, we also constantly reduce the amount of biomass available to us, by methods such as rampant deforestation. This will only widen the ratio of human-made materials to biomass on Earth, scientists say, fast-tracking the start of the Anthropocene age — an unofficial geological epoch when human activity becomes the dominant driver of climate change and environmental transformation. The Anthropocene — if geologists can ever get on the same page about its existence, which they have not so far done — could mean humans are not simply an insignificant blip within geologic time, but rather as impactful as Earth-changing natural disasters of the past, such as volcanoes that wiped out a majority of life on the planet.
While scientists debate whether or not we are in the Anthropocene age, or when the peak of the Anthropocene may arrive, one thing’s for certain — “Some people think that humanity is just one species out of many, and that we’re tiny and the world is huge,” one of the authors of the study, Ron Milo, tells Time. “But our impact is not tiny. Having a number really quantifies that.”
