Earth is a system made up of numerous interacting subsystems like the atmosphere, hydrosphere and biosphere. The sun provides the main energy input that drives processes in these subsystems, while Earth's interior is also an energy source. Humans affect Earth's system through activities that cause issues like pollution, acid rain, and global warming. Resources are either renewable over short time spans through natural processes, like plants and solar energy, or nonrenewable over millions of years, such as fossil fuels.

1. Earth System Science 1.4

2. System Any size group of interacting parts that form a complex whole.

3. Key ConceptHow is Earth a system?Its aim is to understand Earth as a system made up of numerous interacting parts, or subsystems.

4. Key Concepts What is a system?Any size group of interacting parts that form a complex whole.

5. Key ConceptWhere does the energy come from that powers Earth’s systems?One source is the sun, which drives external processes that occur in the atmosphere, hydrosphere, and at Earth’s surface. Earth’s interior is the second source of energy.

6. Key ConceptHow do humans affect Earth’s system?Our actions produce changes in all of the other parts of Earth system. Significant threats to the environment include air pollution, acid rain, ozone depletion, and global warming.

7. Key ConceptWhat makes a resource renewable or nonrenewable? Renewable resources-plants, water, and solar energy-can be replenished over relatively short time spans. Nonrenewable resources –fuels of oil, natural gas, and coal- are created slowly over millions of years.