Call me a pessimist, but I believe it will ultimately destroy humankind (and not just humankind).
Nothing such as Technology can save what humans need the most: love, sharing, relating, etc.
I know more and more people who spend their entire free time on their computer with their hundreds of "friends", yet they feel extremely lonely and depressed.
From a purely scientific point of view though, I partly agree with you that it will solve many problems in a wide range of areas.
Im sorry but I must disagree. I think technology and science will be the tools to save the planet. Humankind have the power to save by itself.