Greenhouse gas, any gas that has a radiation property from the face of Earth to absorb infrarot radiation, thereby leading to a greenhouse effect. Earth’s surface. The most powerful greenhouse gases are carbon dioxide , methane and water vapour. The energy balance of the earth system is greatly influenced by greenhouse gases, although it makes up just a fraction of all atmospheric gases. Greenhouse gas concentrations have changed dramatically over the history of the earth, causing tremendous climate change across a wide range of timescales. In general, greenhouse gas concentrations during warm and cold cycles were especially high.
Many processes affect the production of greenhouse gases. Others work in millions of years, like tectonic movements while others work on hundreds to thousands of years, such as vegetations, rocks, wetlands and ocean sources and sinks. Human activities, particularly the combustion of fossil fuels, as Industrial Revolution has steadily increased atmospheric concentrated gases, including carbon dioxide , methane, ozone and chlorofluorocarbons.
The effects of a greenhouse gas on the atmosphere of the Earth depend on its chemical composition and relative atmospheric concentration. Some gases are able or present in large amounts to absorb infraround radiation, while others have slightly lower absorption ability or are formed in trace quantities only. Radiative forcing is a measure of the effect of a given greenhouse gas or other climatic factor in the amount of radiant energy affecting the earth surface, as specified by the Intergovernmental Committee on Climate Change.
Water vapour is the Earth’s most strong greenhouse gas, but the behaviour of it varies significantly from that of the other greenhouse gases. The primary function of water vapour is not as a direct radiative forcing force, but rather as an input from the environment that affects the continued activities of the system. This is due to the fact that the volume of water vapour in the atmosphere can not be changed by human behaviour in general, but is dictated by the air temperature. The colder the temperature, the more water from the atmosphere is evaporated. In the lower atmosphere, increased evaporation results in higher water vapour concentrations capable of absorbing infrarouge radiation and returning it to the soil.
The most powerful greenhouse gas is carbon dioxide. Natural ambient carbon dioxide sources include volcanic emissions, combustion and natural decay, and aerobic breathing. Via physical, chemical , or biological processes known as “sinks,” these sources are, on average, regulated and appear to eliminate the carbon dioxide from the atmosphere. The terrestrial vegetation, which uses carbon dioxide in photosynthesis, contains essential natural sinks.
Several oceanic processes are also used as carbon sinks. One of these is the “solubility” pump, whereby water containing dissolved carbon dioxide falls down from its top. The biological pump requires the use of marine plants and plantoplankton that live in the upper ocean or by other aquatic organisms that use carbon dioxide to create calcium carbonate skeletons or other structure.
Humans’ behaviours, by comparison, mainly raise the atmospheric CO2 levels through carbon combustion and cement processing. Other anthropological sources include forest burning and land clearing. The global emissions of about 7 gigatons of carbon into the atmosphere are actually attributed to anthropogenic emissions. Anthropogenic emissions constitute roughly three per cent of the total natural source emissions of carbon dioxide and the increased human carbon burden much exceeds the natural sink’s offset capacity.