I recently watched a video that mentioned the “toxic pit problem” of how closed mines turn into toxic lakes full of rainwater and harmful chemicals. Some companies are trying to fix them, but I was wondering if the Earth could “purify” itself if left completely alone?
Like, let’s say all of humanity disappeared tomorrow, could the harmful chemicals be filtered out or dissolved or changed after a billion years?
In: Planetary Science
Do you not remember how much things changed when the world was shut down for 2 weeks during Covid?
Well, yes the water cycle is basically like a giant reverse osmosis filter but really it’s mostly that the earth’s complete biosphere is much more adaptable than humanity is. All humans would die long before all the varieties of plant and animal life would and whatever life remained would gradually take over again. The Anthropocene Epoch is only a blink of the Earth’s eye compared to other Epochs.
Eventually pollution, plastics, and other waste would slowly get diluted or pushed underground through natural geomorphic processes. Think of the historical rock layers.
Harmful is in relation to humans and maybe most animals, not nature. The earth doesn’t really care about what we do, the biosphere will most likely recover anything we can throw at it and we would annihilate ourselves faster than kill the biosphere.
There have been multiple catastrophic events and the mass extinctions to go with it. Given enough time evolution will find ways to live almost anywhere. Some bacteria live off of radiation or snails near steam geysers hotter than the surface of the sun.
Oxygen was once responsible for a mass extinction and then evolution created beings that depended on it to work.
Pollution isn’t killing the earth it’s killing us and the things we depend on.
“Purity” in ecosystems is largely an illusion. There was no coming back from the Great Oxygenation Event, or the Chicxulub Impact, or the Ice Ages, and all of these predated what some now call the “pure” life that predated modern human behavior. It will be the same for the Anthropocene: there is no going back, but life will move on.
The best ‘ELI5’ I have heard on this particular question is “Picture our Earth and its atmosphere as one giant, self-cleaning oven.” Volcanoes actually spew metric tons CO2 and dust into the atmosphere, thousands of gallons of oil seep naturally into the ocean every day, climate change (not man made) is real and actually occurs cyclically. That being said, we as humans, politicians or giant corporations have no right to disregard any of this as an excuse to fuck our one and only home.
I mean, one could argue that the earth is already “pure.” Or rather that it doesn’t need “purifying” even now. Humans are part of nature. We adapt our environment to meet our needs similarly but to a greater degree as a beaver does when it dams a river.
No matter what we do the Earth will continue on spinning and it’s impossible for any actions taken by humans to exterminate all life on the planet. It’ll always bounce back and the natural ecosystem will always balance out so long as life exists. What humans have done in the last three centuries is catastrophic given our limited perspective, and indeed it is catastrophic to the life that lives on Earth today, but three centuries is a fraction of a fraction of a blink of an eye in the scale of Earth’s lifetime and that of evolution.
There’s a really fascinating book on this that I would recommend if you’re interested. It’s called “The World Without Us” by Alan Weisman. He details what would happen to the world if humans were suddenly removed. What would happen to our cities, our monuments, how would nature recover and reclaim what we did. It was very interesting!
If by “purify itself” you mean be habitable to life? Sure. It’s habitable to life today. Even toxic pits are habitable to the right organisms.
If you mean be indistinguishable from pre human Earth? No. Forget thw chemical spills, nuclear waste has half lives of billions of years. They tend to be fairly isolated and therefore not consequential on the planet. But they will be noticeable to an alien race trying to figure out if anything weird happened to this planet.
Nature is pretty resilient. Even if humans were to go extinct, it’ll probably spend some time reclaiming land that was developed, used for mining, etc. New species will evolve to “fill the gaps” left by humans. Most excess greenhouse gases will probably decay or get “scrubbed” from the atmosphere somehow. There will probably always be a certain amount of methane or carbon dioxide in the atmosphere, but they can adjust to more “normal” levels.
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