Answer
See below.
Work Step by Step
If fusion is ever harnessed, there will be an abundance of energy.
Worldwide changes would occur in the oil/gas industries, both economic and political. One can hope there would be peace in the Middle East. In a related effect, global warming would be dramatically reduced.
The products of fusion would also lead to an abundance of heavier elements - let's hope that those with the fusion reactors learn to share the wealth.
