Nicholas Georgescu-Roegen was a very smart man who studied things like economics and mathematics. He worked really hard to understand how the world worked, and he thought a lot about how people use resources.
He had an idea that people were using too much of the Earth's resources, and that this could cause problems in the future. He believed that one day, there might not be enough resources for everyone to use, and that people needed to find ways to use them more efficiently.
He also thought that people needed to learn to live in harmony with nature, instead of trying to control it. He believed that if people understood how the Earth worked, they could find ways to live in balance with it.
Basically, he was a wise man who wanted to help people take better care of the Earth, so that we could all have a better future.