Greenhouse gases global warming potential

GREENHOUSE GASES / GLOBAL WARMING POTENTIAL C02 equivalent emissions from energy-consuming sources (tonnes)... 

Each greenhouse gas differs in its ability to absorb heat in the atmosphere. HFCs and PFCs are the most heat-absorbent. Methane traps over 21 times more heat per molecule than carbon dioxide, and nitrous oxide absorbs 270 times more heat per molecule than carbon dioxide. Often, estimates of greenhouse gas emissions are presented in units of millions of metric tons of carbon equivalents (MMTCE), which weighs each gas by its GWP value, that is, Global Warming Potential. 

Globally, the oxides of nitrogen, NO (nitric oxide), NO2 (nitrogen oxide), and N2O (nitrous oxide), are key species involved in the chemistry of the troposphere and stratosphere. NO and N2O are produced mostly by microbial soil activity, whereas biomass burning is also an important source of NO. Nitric oxide is a species involved in the photochemical production of ozone in the troposphere, is involved in the chemical produaion of nitric acid, and is an important component of acid precipitation. Nitrous oxide plays a key role in stratospheric ozone depletion and is an important greenhouse gas, with a global warming potential more than 200 times that of CO2. 

To evaluate the impact of different greenhouse gases, the IPCC introduced the global warming potential [8c[ (GWP), which is a quantified measure of the impact of each gas compared to carbon dioxide, used as a reference, in a defined time and per unit of mass. The relationship between gigagrams of gas and teragrams of equivalent CO2 is the following ... 

Global warming potential is a measure of how much a given mass (a ton) of greenhouse gas (GHG) is estimated to contribute to global warming, evaluated as its accumulated... 

Notes Well-to-wheel greenhouse gas (WTW GHG) emissions are weighted by their global warming potential. Assumes 84-mpegfuel... 

The ability of these compounds to absorb infrared radiation varies widely from compound to compound, as does their life in the atmosphere before they undergo photochemical reactions or are absorbed in the oceans or on land. Methane has a concentration of only l.Vppmv in the troposphere, which is much less than that of carbon dioxide. On the other hand, each molecule of methane has a global warming potential (GWP) value that is 21 times that of carbon dioxide over the course of 100 years. (Note the GWP value has been developed to compare the ability of each greenhouse gas to trap infrared radiation over 100 years relative to another gas by convention, carbon dioxide has a GWP of 1.) Although methane has a relatively short lifetime (a few years)... 

Figure 21.19 Global warming potentials (GWPs) for a range of greenhouse gases with differing lifetimes, as in Figures 21.17 and 21.18, using CO2 as the reference gas (IPCC, 1995).

Global warming potential (GWP) is calculated for each different greenhouse gas, including CO2, N2O, CH4 and volatile organic compounds (VOCs). GWP is expressed as CO2 equivalent. 

In some isolated cases, an Ar/SFe-mixture has been used. The latter is a greenhouse gas with a high global warming potential, which falls under the Kyoto protocol, (see also Section 4.2.7.1)... 

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