In 1980 William Catton published a book titled Overshoot, which outlined how the scale of the human enterprise had outgrown our planet. Every year scientists at the Global Footprint Network calculate the day humanity crosses into overshoot for that year. They’ve dubbed it Earth Overshoot Day, and it’s coming up. I’m inviting you at the end of this post to predict when that day will fall this year.
What, exactly, is overshoot? It’s a critical concept to understand, because it is directly related to the concept of sustainability and the ability of humankind to stick around.
A simple way to explain overshoot is analogizing Earth’s resources and ecosystems to your savings account at the bank. In Earth’s case, we don’t get to make new deposits into our natural capital account. We have to make good use of what is on the planet. Just as your savings account earns interest, Earth’s resources are replenished. Acorns fall and new trees grow. Plants absorb carbon dioxide and put oxygen back into the atmosphere. Fish reproduce.