This is a very cool visualization. Weirdly, though, the visually apparent proportion of natural vs. human causes seems to change depending on my zoom level.

Plotting this much data presents several challenges. I recently discovered a good guide on the subject of "Plotting Pitfalls" from the Bokeh project:

https://bokeh.github.io/datashader-docs/user_guide/1_Plottin...

I think this visualization suffers a bit from "overplotting".