Part of the issue for me is that I’m attempting to wrangle statistical significance into the discussion, when I haven’t properly stepped back and frames the issue properly. Like you I need to know more about the science as well in order to give a helpful answer.

Suffice to say that statistical significance is only relevant when there is a specific statistical parameter that you want to make a determination about. And in this case I’m not entirely sure what that would be.

Looking specifically at the value you referenced, I think a more useful tool you could look at would be trend decomposition.