![]() Most frozen water is contained in the ice sheets on Greenland and Antarctica, which average about 2 kilometres (1.2 miles) in height. Both hemispheres have about the same amount of sea ice. Because there is more land in the Northern Hemisphere compared to the Southern Hemisphere, a larger part of that hemisphere is covered in snow. This includes sea ice, ice sheets, permafrost and snow cover. The cryosphere contains all parts of the climate system where water is solid. Brackish water is found in estuaries and some lakes, and most freshwater, 2.5% of all water, is held in ice and snow. It contains seawater with a salt content of about 3.5% on average, but this varies spatially. The ocean covers 71% of Earth's surface to an average depth of nearly 4 kilometres (2.5 miles), and ocean heat content is much larger than the heat held by the atmosphere. The hydrosphere proper contains all the liquid water on Earth, with most of it contained in the world's oceans. Not only does the hydrological cycle determine patterns of precipitation, it also has an influence on the movement of energy throughout the climate system. The hydrological cycle is the movement of water through the atmosphere. This causes surface temperatures to rise. Some trace gases in the atmosphere, such as water vapour and carbon dioxide, are the gases most important for the workings of the climate system, as they are greenhouse gases which allow visible light from the Sun to penetrate to the surface, but block some of the infrared radiation the Earth's surface emits to balance the Sun's radiation. It consists mostly of inert nitrogen (78%), oxygen (21%) and argon (0.9%). The atmosphere envelops the earth and extends hundreds of kilometres from the surface. Changes can be amplified by feedback processes in the different climate system components.Ĭomponents of the climate system Human activity also releases cooling aerosols, but their net effect is far less than that of greenhouse gases. Accumulation of heat-trapping greenhouse gases, mainly being emitted by people burning fossil fuels, is causing global warming. These external forcings can be natural, such as variations in solar intensity and volcanic eruptions, or caused by humans. The climate system can change due to internal variability and external forcings. In addition, different chemical elements, necessary for life, are constantly recycled between the different components. The water cycle also moves energy throughout the climate system. Circulation in the atmosphere and oceans is primarily driven by solar radiation and transports heat from the tropical regions to regions that receive less energy from the Sun. Climate is the statistical characterization of the climate system, representing the average weather, typically over a period of 30 years, and is determined by a combination of processes in the climate system, such as ocean currents and wind patterns. The five components of the climate system all interact.Įarth's climate system is a complex system having five interacting components: the atmosphere (air), the hydrosphere (water), the cryosphere (ice and permafrost), the lithosphere (earth's upper rocky layer) and the biosphere (living things).
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