Anthropogenic Sources Of Energy

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Methane. Methane is the second most prevalent GHG emitted by anthropogenic sources, with anthropogenic emissions accounting for approximately 70-80% of the total CH4 emissions (EPA, 2015; Johnson and Johnson, 1995). Emissions of methane have increased exponentially from the pre-industrial period to present day. During the years 1000 – 1750, CH4 concentrations in the atmosphere were approximately 700 parts per billion by volume (ppbv) (IPCC, 2001; EPA, 2015). In the year 2015, CH4 concentrations had risen to approximately 1,864 ppbv, an increase of 166% (NOAA/ ESRL, 2015b). Although CH4 has a relatively short AL of only 12 years, it has a GWP value of 25 (IPCC, 2013; EPA, 2015), which was recently updated to a GWP value of 28 to 36…show more content…
Due to the complex process involving OH, when CH4 emissions increase, OH concentrations decrease, which can increase the AL of CH4 (IPCC, 2013; EPA, 2015). Nitrous Oxide. Nitrous Oxide emissions have increased by 20%, from 270 ppbv during the pre-industrial period to approximately 316 ppbv in the year 2000 (IPCC, 2001; NOAA/ ESRL, 2015b). Although the total N2O emissions are much lower than CO2; N2O has an atomic lifetime of 114 years and a GWP value of 298, therefore, it is approximately 300 times more powerful at trapping heat in the atmosphere and increasing the GHE when compared to CO2 (EPA, 2015). The main sources of anthropogenic N2O emissions includes; agricultural soils (nitrogen-fixing crops and forages), fertilizers (synthetic and manure), feces deposition from livestock, fossil fuel combustion (predominantly mobile combustion), nylon and nitric acid production, waste water treatment, and waste incineration and biomass burning (EPA, 2015).
Trace gases and small molecules. Other trace gases and small molecules that influence the GHE and GW include; ozone (O3), halocarbons, carbon monoxide (CO), nitrogen oxides (NOx), non-methane volatile organic compounds (NMVOCs), and aerosols (EPA, 2015). Atmospheric
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