Earth as a System: Energy, Matter, and Life
One Earth, five spheres
See the Earth as five connected spheres.
A system is something where things go in, something happens, and something comes out. Making tea is a system: water, leaves, milk and sugar go in, they boil together, and tea comes out. The Earth is a system too. It runs on flows of energy and matter, powered mainly by the Sun (and also by the Earth's hot interior and by chemical reactions).
Scientists divide the Earth into five spheres:
| Sphere | What it is | Indian examples |
|---|---|---|
| Geosphere | Rocks, soil, landforms, the Earth's interior | The Deccan plateau, the Thar desert |
| Hydrosphere | Liquid water: oceans, rivers, lakes, groundwater | The Ganga–Brahmaputra rivers |
| Cryosphere | Ice and snow | Himalayan glaciers, snow in Ladakh |
| Atmosphere | The air around the Earth | Cleaner air in mountains and forests |
| Biosphere | All living things and their homes | Mangroves, forests, farms, plankton, coral reefs |
(Cryo means cold.)
Follow one raindrop through all five. Sea water evaporates (hydrosphere to atmosphere). It forms a cloud and rains on your roof (geosphere). It soaks you and the plants (biosphere). Or, high in the mountains, it falls as snow (cryosphere), which melts into a river and flows back to the sea. Nature doesn't come in separate boxes; we only divide it to study it.
Change one sphere and the others change too:
- Less snow in winter → less water in the lake in summer → less grass for the sheep.
- A warmer Arabian Sea → more evaporation → an unsteady south-west monsoon → floods in some places, drought in others.
- A warmer atmosphere → glaciers and polar ice melt faster → flooding in low-lying areas and, in the long run, rising seas that threaten coastal cities and habitats.
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