Advance to help Humanity

[Excited Penguin]

Like others have said, fusion power. That's a world changer. Climate change goes away and large-scale desalination of seawater becomes practical.

A working space elevator is a close second.

It is my understanding that climate change won't go away for another thousand years or so, no matter what we do. We can just hope to stop it from getting too bad in the future, we can't stop it altogether - it's too late for that. And maybe it's too late for anything, really. But that's just my understanding.