The subfield of environmental sociology studies the way humans interact with their environments. This field is closely related to human ecology, which focuses on the relationship between people and their built and natural environment. This is an area that is garnering more attention as extreme weather patterns and policy battles over climate change dominate the news. A key factor of environmental sociology is the concept of carrying capacity, which describes the maximum amount of life that can be sustained within a given area. While this concept can refer to grazing lands or to rivers, we can also apply it to the earth as a whole.