On a technical point, buzsaw seems to be correct. In mathematics we can say that f is increasing over time if df/dt is positive - apologies for introducing calculus.
That's fine ...
No, actually it is not fine. When the occurance of events is highly variable with some possible cyclical variations thrown in then to simply find a positive slope with time is not adequate.
It is necessary to sort out the variation and any cyclical patterns and from that determine if there is a real positive signel left. It requires a fair amount of mathematical care. I've not done anything with something as complex as weather patterns and earthquakes but the very simple stuff I have touched taught me that. I couldn't do it again today (forgot a lot

).