Will change in ocean salinity cause a change in climate overall? Why or why not?

Yes

Explanation:

Ocean play very important role in climate change. Change in the salinity of ocean definitely going to affect climate because changes in salinity have effect on water density.

Change in density allows changes in the movement of seawater and shift in climate pattern. if salinity will increase, water will become heavier and sink deep in ocean, which joins the currents that circulate all over the world. These currents affects the transport of heat and affect the rainfall pattern, example of such currents is gulf stream.

So, stable salt densities or salinity in the oceans keep the earth's climate in balance.