The following two quotes make exactly the same point in two very different ways - one uses whimsical humour and irony: the other expresses it bluntly in five words.
"In the space of one hundred and seventy-six years, the Lower Mississippi has shortened itself two hundred and forty-two miles. That is an average of a trifle over one mile and a third per year. Therefore, any calm person, who is not blind or idiotic, can see that in the Old Oölitic Silurian Period, just a million years ago next November, the Lower Mississippi River was upwards of one million three hundred thousand miles long, and stuck out over the Gulf of Mexico like a fishing rod.
And by the same token, any person can see that seven hundred and forty-two years from now the Lower Mississippi will be only a mile and three-quarters long, and Cairo and New Orleans will have joined their streets together, and be plodding comfortably along under a single mayor and a mutual board of aldermen. There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact."
(Mark Twain, "Life on the Mississipi, Chapter 17)
"Beware of forecasters with rulers."
(This is a slogan which I hung above my desk while working as a forecaster for BT in the last years of the 20th century. It was a slight paraphrase of the words which The Economist, magazine had used as the title of an article published in about 1995 on the dangers of extrapolating trends forward and assuming they will continue indefinitely - or at all - unless you have very good reason to know that they can and will. Their exact wording was "Beware of Optimists with rulers.")