# Time Series - Is there increasing variance?

I can't figure out if this time plot has increasing variance or not. From my initial guess of the time plot, I would say no but I've taken the difference and it looks like variance is increasing slightly. I've subsequently taken a log transformation and differenced that also where the variance looks to be constant. I'm just wondering is the data variance increasing so much that a log transformation needs to be taken in order to start making the series stationary? I've attached all plots below. , ,