In any control system that is functioning properly, the methods used to control a signal won’t be correlated with the signal they’re controlling.
Worse, there will be several variables that DO show relationships, and may give the wrong impression. You’re looking at variables A, B, C, and D. You see that when A goes up, so does B. When A goes down, C goes up. D never changes and isn’t related to anything else — must not be important, certainly not related to the rest of the system. But of course, A is the angle of the road, B is the gas pedal, C is the brake pedal, and D is the speed of the car.
In the past, GDP and resources use have always been tightly correlated. But this is just drawing a line through some data — it’s not based on any deep theory. And in fact, these correlations can change very quickly. Just as one example, here’s energy use versus GDP since 1949.
If you were sitting in 1970, you could look at this curve and claim, very confidently, that economic growth requires concomitant increases in energy use. And you’d be wrong. Because the trend is your friend til the bend at the end.
Years ago a friend of mine had a dream about a strange invention; a staircase you could descend deep underground, in which you heard recordings of all the things anyone had ever said about you, both good and bad. The catch was, you had to pass through all the worst things people had said before you could get to the highest compliments at the very bottom. There is no way I would ever make it more than two and a half steps down such a staircase, but I understand its terrible logic: if we want the rewards of being loved we have to submit to the mortifying ordeal of being known.