Yeah, but I'm sure the first person to find oil spurting out of the ground didn't have to worry about it running out anytime soon. Ingenious peoples cutting down the first tree on Easter Island never saw the trees running out. We a humans tend to underestimate our impact as it scales and grows over time. But as growth goes exponential, industries scale, and population explodes, the story, elapsed over time, changes dramatically. Look how far technology has advanced in 100 years. Who knows what crazy shit will go down in the next 300. A billion kilograms might just be "one truckload" out of hundreds being imported daily. We have no idea how big it could scale.

You're right, it's a metric shit-ton of material to make any difference, but to say we'll never have done that much is just impossible.

By all means worry about environmental problems. Like the various suggestions on this page to crash-land a mining asteroid on Earth---let's not do that.

But at the moment the possibility of changing the mass of the earth has to be really low on the list of environmental worries. When we're moving a billion kilograms an hour, net, to Earth, I will sign your petition and donate to your campaign.

I think you took me the wrong way. I'm not trying to be political/environmental. I'm curious on the broader scheme "sci-fyi-ness" of what the future could look like, and how we would get in such places. And the Sociological causes/effects of such futures.

That, and the theoretical thought of what would happen should we impact the weight of the world to the point of it having a noticeable impact on earths astronomical characteristics intrigues me.

Fair enough, and sorry. Sci-fi version: once you're moving that sort of tonnage, logarithmically speaking you're closer to Ringworlds and Dyson spheres than you are to near-future asteroid mining.