[I]f one goes back to (say) 1850 and spawns a parallel universe in which one instantly and without pollution kills all the humans, then runs the clock forward to today, is there more CO2 in our universe than in that parallel universe’s 2014? In that case, my even-money bet would be “yes”. But I don’t feel hugely strongly about that. I also don’t care or think it is germane to much of anything.
We would like to disclaim, expressly and in full, any responsibility should some farking maniac transport himself back to 1850 and destroy all of mankind. If we wait long enough, we can do it ourselves, thank you very much. And we’ll probably do it with financial derivatives and similar bogus constructs. This is the way the world ends, not with a whim, but a banker.