Herman Daly is a famous economist who helps us understand why it's important to take care of the environment. He said that our natural resources, like trees, water, and air, are like a bank account – if we use them all up, we won't have any left to use in the future! He teaches us to be careful about how much of our natural resources we use, so we can save some for later. He calls this idea "sustainable development," which means taking care of the environment now and into the future.