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During this time, the atmospheric carbon dioxide concentration has varied between 180 and 210 ppm during ice ages, increasing to 280–300 ppm during warmer interglacials. [ 115 ] [ 116 ] CO 2 mole fractions in the atmosphere have gone up by around 35 percent since the 1900s, rising from 280 parts per million by volume to 387 parts per million ...
Although individual CO 2 molecules have a short residence time in the atmosphere, it takes an extremely long time for carbon dioxide levels to sink after sudden rises, due to e.g. volcanic eruptions or human activity [17] and among the many long-lasting greenhouse gases, it is the most important because it makes up the largest fraction of the ...
As the source of carbon in the carbon cycle, atmospheric CO 2 is the primary carbon source for life on Earth. In the air, carbon dioxide is transparent to visible light but absorbs infrared radiation, acting as a greenhouse gas. Carbon dioxide is soluble in water and is found in groundwater, lakes, ice caps, and seawater.
For example, methane has a GWP over 20 years (GWP-20) of 81.2 [2] meaning that, a leak of a tonne of methane is equivalent to emitting 81.2 tonnes of carbon dioxide measured over 20 years. As methane has a much shorter atmospheric lifetime than carbon dioxide, its GWP is much less over longer time periods, with a GWP-100 of 27.9 and a GWP-500 ...
In a given year between 10 and 100 million tonnes of carbon moves around this slow cycle. This includes volcanoes returning geologic carbon directly to the atmosphere in the form of carbon dioxide. However, this is less than one percent of the carbon dioxide put into the atmosphere by burning fossil fuels. [2] [32] [37]
As a measure of atmospheric carbon change, the TCRE parameterizes how sensitive the climate is to carbon dioxide to formulate a value that is the temperature change (°C) per trillion tonnes of carbon emitted (Tt C). [6] [5] This is represented via the following formula:
Radiative forcing is defined in the IPCC Sixth Assessment Report as follows: "The change in the net, downward minus upward, radiative flux (expressed in W/m 2) due to a change in an external driver of climate change, such as a change in the concentration of carbon dioxide (CO 2), the concentration of volcanic aerosols or the output of the Sun." [3]: 2245
The one-level atmospheric model can be readily extended to a multiple-layer atmosphere. [ 8 ] [ 9 ] In this case the equations for the temperatures become a series of coupled equations. These simple energy-balance models always predict a decreasing temperature away from the surface, and all levels increase in temperature as "greenhouse gases ...