An international team of researchers recently released a meta-analysis of over 1600 studies from around the world which suggests that urbanization is affecting the way many plants and animals evolve. For example, plants growing in the city may release larger, heavier seeds than their rural cousins. Heavier seeds that drop closer to the parent are more likely to land in a patch of dirt where they can grow, while smaller seeds would blow further away, possibly landing in the middle of a street or a parking lot. In a rural setting, blowing further away wouldn’t matter as much, but for a city plant, this is potentially the difference between life and death. Plants and animals adapting to a completely human-created landscape is one more indication that we have passed an important threshold, entering a time called the Anthropocene.
The Earth’s past is broken up into different chapters that define important phases of geological history. The biggest chunks of time are called eons, which last a half billion years or more. Smaller than eons are eras, which are still quite long, at several hundred million years apiece. Next are periods, such as the Jurassic (which lent its name to a popular movie about dinosaurs). Subsets of periods are called epochs, which last in the neighborhood of tens of millions of years. The Anthropocene, named after the vast changes that humans are imposing upon the world’s ecosystems, is considered to be an epoch. While scientists argue among themselves about whether the Anthropocene epoch is a real thing and if so, when it started, the concept itself is useful for understanding the scale of changes we have introduced.
We’re not the first living things to radically change the planet. For example, the Great Oxygenation Event, which occurred roughly 2.5 billion years ago, was probably the Earth’s first mass extinction event. There were no animals yet, and no complex plants with leaves and flowers. Life was far simpler back then, and consisted mostly of bacteria and algae. One form of life emerged, cyanobacteria, which could photosynthesize (make its own food from the sun, a trick it passed on to leafy plants). These bacteria produced so much oxygen as a waste product that it not only bonded with any iron it found in the environment (forming bands of rusty rock that can still be found today), it went on to suffocate most of the life on Earth. Luckily, there were some organisms that could use the oxygen, or we wouldn’t be here today.
Geological changes, such as between eras and periods, leave visible clues in the layers of the Earth, such as the rust left behind by the cyanobacteria, or a change in the fossil record as species go extinct and new ones take their place. As we enter the Anthropocene, we are certainly not lacking for measurable changes that will be clear as day to any far future scientists that find themselves studying our rocks. One of these is the sheer amount of plastic that we’re leaving behind.
Does Plastic Pollution Define the Anthropocene by The 5 Gyres Institute
There’s always a few species coming or going on life’s grand stage. Ever since we humans started tossing rocks around, building settlements, and especially industrializing, though, we’ve been knocking out a shocking number of other species, 100 times faster than normal. Three quarters of them, big and small, and lots we will probably never know existed, will be lost forever. We’re in the middle of the sixth worldwide mass extinction, which is as clear an indication as any that the times, they are a-changin’.
Other changes are going on all around us as the Anthropocene rolls along. We’re in danger of losing many herbal medicines, which 80% of the world’s population still relies upon for healthcare. We’re draining aquifers of fresh water and eroding soil with industrial agriculture. We’re killing off the bees, acidifying the ocean, bleaching the coral, razing the forests, puffing out a blanket of methane and carbon dioxide that warms the atmosphere, causing climate instability, flooding the coasts, and the saddest part of all is that we’re wise to it all, but have no real intention of stopping.
Yet somehow, as we kick the ladder out from beneath our own feet, we’re so confident that we have a long and prosperous future ahead, that we’re naming an entire epoch after ourselves. Epochs, remember, last for tens of millions of years. We haven’t even been here a quarter of a million years yet, and we’re trashing everything we need to live. What makes us think we have more than a whisper of time left, let alone that we’re on our way to flying cars and Star Trek level tech?
That’s why it’s unlikely that the Anthropocene is a real epoch. If anything, we are the end of an epoch, a tiny layer of ashes and carbonized plastic that marks the finish of the Holocene as we take the rest of the biosphere down with us, not unlike the asteroid that killed the dinosaurs. It appears that following the cyanobacteria off of history’s main stage is easier, in the end, than making hard choices and looking at our priorities. Just like the Norse gods facing Ragnarok, though, this is also a test of our moral strength. Our character will be defined not by what we do when times are easy, but by our honor when we face the unwinnable battle.