I have my doubts about war, although I don't think most wars really come down to conflicts of terminal values. I'd hope not, anyway.

However as for the rest, if they're solvable at all, intelligence ought to be able to solve them. Solvable means there exists a way to solve them. Intelligence is to a large degree simply "finding ways to get what you want".

Do you think energy limits really couldn't be solved by simply producing through thought working designs for safe and efficient fusion power plants?

ETA: ah, perhaps replace "intelligence" with "sufficient intelligence". We haven't already solved all these problems already in part because we're not really that smart. I think fusion power plants are theoretically possible, and at our current rate of progress we should reach that goal eventually, but if we were smarter we should obviously achieve it faster.