At our current rate of growth, there'll be 10 billion souls on this planet, with zero fossil fuels, zero coal and other natural resources. Wars will be fought over water. The burgeoning populations will mostly be in third world countries.
Will technology save the day?.....maybe. Will we change our ways to avoid the impending train wreck?.....doubtful. Will there be some cataclysmic event that brings us down to more sustainable levels...say 3 billion?.....probably