Fitting puzzle pieces together is analogous to how we study the Earth. By considering Earth as an integrated system, with many interlocking parts, we are able to understand the larger picture of global change.

Earth is unique in being able to sustain life as we know it, and scientists are learning more about Earth as a system and the specific sets of factors involved in keeping our planet habitable. 

Our climate depends on the whole Earth system. The Sun, land (geosphere), ocean (hydrosphere), ice (cryosphere), and living organisms (biosphere) interact with the atmosphere in the climate system.

The atmosphere is a mixture of gases that surrounds the planet. Without the atmosphere, life on Earth wouldn't be possible.

The biosphere includes all life on our planet. Scientists study how biological processes, like photosynthesis, affect other parts of the Earth system. Humans are only a small fraction of Earth's biosphere, but our actions have a large impact.

There are many different types of frozen water on Earth. Collectively, they are known as the cryosphere and are tied to the other parts of the Earth system.

The geosphere includes the rocks and minerals on Earth – from the molten rock and heavy metals in the deep interior of the planet to the sand on beaches and peaks of mountains. Beyond these parts, the geosphere is about the processes responsible for the constant recycling of rocks on Earth.

The hydrosphere contains all of the water on Earth's surface, including the ocean as well as freshwater.

All of the atoms that are building blocks of living things are a part of biogeochemical cycles. The most common of these are the carbon and nitrogen cycles.

Accounting for all the energy that enters and leaves the Earth system helps us understand how the planet maintains a habitable temperature. This accounting of energy is known as Earth’s radiation budget.

See how Earth's temperature would change if the Sun's brightness increased or dimmed or if Earth's albedo was different.

Earth's biomes change over long time periods as a result of natural cycles, but can change more abruptly due to human impacts. Earth's forest biomes in particular are changing, as a result of agriculture, outbreaks of tree-killing pests, and wildfires.

As Earth’s population increases, human impacts on all the parts of the Earth system also increase. What are these impacts to air, water, land, and life, and why do we refer to our present time as the Anthropocene? 

Learn about Earth systems, why they are variable, and how scientists are studying them.

Examine the current and potential impacts of climate change.

We caused the problem but also have the ability to make the tough but necessary changes. Find out how.