Wild mammal biomass has declined by 85% since the rise of humans
Going off on a tangent, but the scale of production is very hard to grasp.  I'm probably not the first person to observe this, but I once did some napkin math about steel production, and what I realized kind of blew me away.  About 1.9 billion tonnes in 2020.  Like with billions of dollars, I have no intuition for such numbers.  Context is needed.Global steel production just before WW I was about 70 million tonnes.  So production has increased about thirty-fold in one century.  That wasn't so shocking to me, at first.  But 1910 was not the beginning of the industrial era; things had been under way for more than a century then.  Railroads.  Ocean liners.  Factories.  Knives and rivets for fabric owned by hundreds of millions of people.  Dozens of skyscrapers in New York by then; the Brooklyn Bridge hung on thousands of tonnes of cable.  All made out of steel.Then it struck me.  A few million tonnes a year in 1850.  70 million tonnes in 1910.  All of it adds up to less than 1900 million tonnes.  Every single tonne of steel manufactured by humans from prehistory until about a century ago -- the entire output of the industrial revolution -- amounts to less than one year at current production.