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Carbon dioxide equivalent (CDE) and Equivalent carbon dioxide (e) are two related but distinct measures for describing how much global warming a given type and amount of greenhouse gas may cause, using the functionally equivalent amount or concentration of carbon dioxide () as the reference. == Global warming potential == (詳細はquantity that describes, for a given mixture and amount of greenhouse gas, the amount of that would have the same global warming potential (GWP), when measured over a specified timescale (generally, 100 years). Carbon dioxide equivalency thus reflects the time-integrated radiative forcing of a quantity of ''emissions'' or rate of greenhouse gas emission—a ''flow'' into the atmosphere—rather than the instantaneous value of the radiative forcing of the ''stock'' (concentration) of greenhouse gases ''in the atmosphere'' described by e. The carbon dioxide equivalency for a gas is obtained by multiplying the mass and the GWP of the gas. The following units are commonly used: *By the UN climate change panel IPCC: billion metric tonnes of CO2 equivalent (GtCO2eq). *In industry: million metric tonnes of carbon dioxide equivalents (MMTCDE). *For vehicles: g of carbon dioxide equivalents / km (gCDE/km). For example, the GWP for methane over 100 years is 25 and for nitrous oxide 298. This means that emissions of 1 million metric tonnes of methane and nitrous oxide respectively is equivalent to emissions of 25 and 298 million metric tonnes of carbon dioxide.〔(IPCC AR4 WG1, Table 2.14, p.212 )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Carbon dioxide equivalent」の詳細全文を読む スポンサード リンク
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