Not necessary, because even if there are some nonrenewable resources for which are no renewable replacements, that’s consistent with the author’s claim that we might need to do “without” metal ore. That acknowledges the possibility that we might run out of a nonrenewable resources and be unable to replace it.

Necessary, because if it were not true — if we CAN indefinitely (forever) replace exhausted nonrenewable resources (like metal ore) with other nonrenewable resources — then we don’t necessarily have to do without metal ore or turn to a renewable resource. We might be able to keep using nonrenewable replacements for metal ore.

Not necessary, because even if a renewable resource CAN be exhausted by human consumption, the author never suggested that we won’t run out of renewable resources. The author’s position is that we will run out of a nonrenewable resource like metal ore, but she takes no position on whether we might also run out of renewable resources.

Not necessary, because even if consumption of nonrenewable resources WILL increase in the near future, the author’s position is just that “eventually” we will run out of nonrenewable resources. The author doesn’t have to believe that we’ll run out in the near future or that consumption patterns won’t increase in the near future.

Not necessary, because even if we CAN do without nonrenewable resources, that’s consistent with the author’s claim that we might need to “do without” a nonrenwable resource such as metal ore.