One side of the coin is that globalisation could be causing an increase in the gap between rich and poor.
Another side of the same coin maybe that globalisation is causing the number of people living in extreme poverty to decrease. 
In 1990 the number of people living in extreme poverty was 1960 million (37% of world population). Both the number and percentage have been coming down since then, the latest figures I have are for 2015 with 707 million living in extreme poverty (9.6% of world population)
Source: www.ourworldindata.org
I am careful not to assert that globalisation is causing this. Yes, there is a correlation, but there are so many other things also happening that could be causing it. Correlation does not proof causation.
We can assert with reasonable confidence that since 1990:
- globalisation has been happening
- the gap between rich and poor has been increasing
- the number of people living in extreme poverty has been decreasing