The Anthropocene Era refers to the period of time humans have had a measurable global impact on Earth's ecosystems. Though it's clear we're currently living in it, scientists have long debated when exactly this epoch of human dominance over the planet first began.
Did it start with the advent of agriculture around 10,000 years ago? With the Industrial Revolution? With the first explosions of nuclear weapons in the 1940s? As it turns out, new data suggests it may have actually started in the year 1610.
What happened in 1610 that made it such a tipping point for humanity's impact on Earth? According to Simon Lewis, an ecologist at University College London, and geologist Mark Maslin of Leeds University, a "golden spike" can be seen in the global geological record in this year — a threshold, if you will — which can be directly attributed to humans, reports the Independent.
Two global signatures appear in 1610: Pollen from imported New World crops begins to appear in Europe, and a massive dip in carbon dioxide levels can be seen in Antarctic ice cores dating to that time. Both of these events are a direct result of increased trade and transport of animals and plants across the Atlantic Ocean — a barrier that had previously kept the New and Old Worlds separated for millions of years.
In the case of the global dip in carbon dioxide, Lewis and Maslin believe this to be the result of the deaths of millions of indigenous people in the aftermath of European colonization. As many as 50 million Native Americans died in the aftermath of European expansion into the New World, mostly as a result of infectious diseases such as smallpox. As their numbers dwindled, the resultant loss in agriculture allowed forests to re-grow throughout the Americas. These expanded forests scrubbed the atmosphere of carbon dioxide.
"In a hundred thousand years, scientists will look at the environmental record and know something remarkable happened in the second half of the second millennium," said Lewis. "They will be in no doubt that these global changes to Earth were caused by their own species. The anthropocene probably began when species jumped continents, starting when the old world met the new."
Lewis and Maslin contend that this is the first time that human actions had a truly global impact. The bridging of the Old and New Worlds fundamentally changed the entire biosphere of the planet. This was not just a regional impact; its ecological footprint stretched around the world.
"We humans are now a geological power in our own right, as earth-changing as a meteorite strike. Historically, the collision of the old and new worlds marks the beginning of the modern world," Lewis added.