The Climate System
Figure 1: The global climate system (bold type), processes and interactions (thin arrows) and aspects that can change (bold arrows) [IPCC].
The climate system has five components: the atmosphere, the hydrosphere( water cycle), the cryosphere (frozen areas), the land surface and the biosphere (where plants and animals live).
The climate system is extremely complex: Its components interact with each other through physical, chemical and biological processes on a wide range of space and time scales. Although the components of the climate system are very different, they are all interrelated. For example...
All components of the climate system are interrelated.
The water cycle is one way that the atmosphere and ocean interact. Water evaporating from the ocean causes the ocean to cool and become saltier; this increases the density of seawater and hence influences ocean currents. Water vapor from the ocean condenses in the atmosphere, giving off heat and thereby affecting winds. The condensed water also can form clouds and fall to the Earth. Some precipitation reaches the ocean again as it runs off the land, which, like precipitation falling on the ocean, decreases salinity and influences ocean currents.
More examples of interactions:
- The atmosphere and oceans exchange carbon dioxide. CO 2 dissolves in cold polar water and sinks into the deep ocean. It is released by “outgassing” in warm upwelling water near the equator.
- Sea ice hinders the exchanges of heat, water, and gases between atmosphere and oceans.
- The biosphere – where plants and animals live both on land and in the ocean -- influences the carbon dioxide concentration in the atmosphere through photosynthesis and respiration.
- The terrestrial biosphere influences the water cycle by taking in liquid water from the soils and releasing it as water vapor (evapotranspiration) to the atmosphere.
- The optical properties (i.e., the albedo) of the biosphere (land cover) and cloud cover influence how much solar radiation is reflected upward.
Next: Climate Variables