The human population is expected to exceed 9 billion people by 2050. From a geographical systems perspective, which of the great systems (e.g., lithosphere, hydrosphere, etc.) do you see being affected the most by a growing human population? Support your answer. The human population is expected to exceed 9 billion people by 2050. From a geographical systems perspective, which of the great systems (e.g., lithosphere, hydrosphere, etc.) do you see being affected the most by a growing human population? Support your answer.