Happy Belated Overshoot Day!
Overshoot Day is a concept that illustrates how humans are using more resources than can be sustained. According to the Overshooters calculations, we'd need about 1.5 Earths to remain sustainable. There are criticisms of the methods of calculation but I think the illustrative value of the concept is undeniable. And sufficiently depressing to be included here. :)
These are some good links that discuss it: