What If? The Sietch has to evacuate Earth in 1800.

[Abhorsen]

I think that the various arcologies we got provided with in the OP could keep us alive for the 150 years the ROB wants to give us.
However if we fail we get sent hole physically aged to current age + 150, so if we don't jump through hoops we don't get massively extended lifespans and all the nice goodies.

Honestly, I'd rather save all of humanity than get the reward at the end. I still think my secret keeping idea is optimal in that regard. I'd live for 100 something years as a wizard in the 1800s. Not the worst thing in the world. Note we don't even get sent back with my solution, so we could probably barter with Flamel and ask for a philosopher's stone or some such for all our hard work.

 

[Agent23]

Honestly, I'd rather save all of humanity than get the reward at the end. I still think my secret keeping idea is optimal in that regard. I'd live for 100 something years as a wizard in the 1800s. Not the worst thing in the world. Note we don't even get sent back with my solution, so we could probably barter with Flamel and ask for a philosopher's stone or some such for all our hard work.

Yeah, that is the noble thing to do, and my "turn everyone to stone and put them in storage" approach can do the same, and whatever we say and do humanity bound to just one planet when we have the objective of spreading it through the solar system and to other stars is a good idea.
Also, asteroid mining.

 

[Carrot of Truth]

1850 hmm wonder if it would be too late to utterly erase Karl Marx and all of his writings from the timeline.

 

[Bassoe]

The problem with petrifying the muggles for storage until the asteroidical ash rains out of the atmosphere and the "nuclear" winter clears is, why'd they trust us? I don't trust us or that this wouldn't be part of some cunning scheme to get rid of them and I'm one of us. Herding the entire population into petrification camps isn't something that could be settled with a few magic tricks in front of national leaders to demonstrate our bona fides as wizards, but which would literally necessitate conquering the world to achieve.