When humans are gone, nature will reclaim our cities and break down much of what we've built. But some of the things we've made will last much longer than others, and they're probably not the things you'd expect.I used to work with zebra mussels, so I'm surprised I've only mentioned them once here and that was a dozen years ago. It was about time I mentioned the invasive species again and what it's done to the Great Lakes ecosystem. That counts as a sign of human presence, because the bivalves wouldn't be in North America without human assistance.
While I'm not surprised that glass and ceramics will last millions of years — one of the stories I tell my students is about quartz grains being eroded and redeposited a dozen times over a billion years, and glass is made from quartz — finding out that bronze survives for thousands of years is something that I should have realized long ago. After all, the Bronze Age in Europe ended nearly 3,000 years ago, and the bronze artifacts from then have survived all that time.
Something else I expected as a sign of human presence was plastic. Hank Green didn't list that, but he did discuss spheroidal carbonaceous particles. So there is something special about the soot we produce from burning fossil fuels!
That's a wrap for today's collapse-themed entry. Stay tuned as I return to entertainment tomorrow.
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