Cold would be if you scrap the unwanted population (remember soylent green?).
Jettison population gives them the quantum incertainty chance, that they might land in a place where they can survive.
I wonder how exactly you jettison people from a planet...hmm...rocket boosters?...gigantic slingshot?...or jus t the old fashioned walk-the-plank-off-the-edge-of-the-world?