You can't use that tool to solve that problem.

You can't? So much the worse for your species. I quite possibly couldn't either. I'd probably at least think about it for five minutes first. I may even make a phone call first. And if I and my advisers conclude that for some bizarre reason "no further effect beyond this utterance" is better than any other simple wish that is an incremental improvement then I may end up settling for it. But I'm not going to pretend that I have found some sort of way to wash my hands of responsibility.

Meanwhile, you have <= 70 years to solve it another way.

Yes, that's better than catastrophic instant death of my species. And if I happen to estimate that my species has 90% chance of extinction within a couple of hundred years then I would be making the choice to accept a 90% chance of that doom. I haven't cleverly tricked my way out of a moral conundrum, I have made a gamble with the universe at stake, for better or for worse.

Relevant reading: The Parable of the Talents.