No, I meant in nature. In all of the natural world. Physics through economics and everything in between including technology. (Hint: nothing is exponential -- it always levels off. Otherwise we would have been consumed by it.) I would be genuinely surprised and extremely curious to see any natural phenomenon that maintains exponential growth.

I guess compound interest could be considered indefinitely exponential, but you eventually reach a barrier in what's insured and it is a relatively small exponent. Also, is it still savings if you never spend it? I wonder what is the longest continuous account in banking that has never been touched.

Anyway, that is a tangent and a somewhat artificial scenario. Can you name a naturally occurring scenario? I would accept technology if you could show that it isn't going to level out like all other natural phenomenon.