Definition: The idea that humans can and should use resources in a way that ensures their availability for future generations, promoting environmental sustainability and social equity in resource access.

Real-world example: You can think of it like a pizza party - if you take all the slices for yourself, your friends get none and your next pizza party might be a lonely one!

Definition: Areas beyond any nation state's political reach, in need of collective management and protection. As per UNEP, these are: the high seas, Antarctica, the atmosphere, and outer space.

Real-world example: The air we breathe is a global common! No single country can claim it, but if one nation pollutes heavily, it affects the air quality for everyone.

Definition: Renewable resources (e.g., fish) aren't naturally depleted as long as their usage doesn't exceed their natural regeneration pace, the maximum sustainable yield. Over-exploitation leads to resource depletion and scarcity.

Real-world example: Imagine you're picking apples from a tree. If you pick more than the tree can grow back, there will eventually be no more apples for anyone.