Emissions from fossil fuels

These plants would need to use carbon capture equipment or their estimated carbon emissions could equal the fossil fuel emissions from the past 250 years. Carbon capture and storage (CCS) is an important research area but widespread commercial use may be years away. 

Cutter and Church (13) have determined selenium species in western Atlantic precipitation so that the emission sources using this sulfur analogue, which is enriched in fossil fuels (primarily coal), can be more exactly identified. The results show a correlation of both total Se and the Se IV Se VI ratio with increasing protons and excess sulfur in precipitation from Lewes, Delaware, and on Bermuda. Their hypothesis is that, although some reduced forms (1 nM/kg) may come from background oceanic emissions, most oxidized Se is a reflection of fossil-fuel emissions from North America. 

Fossil fuel emissions alter the isotopic composition of atmospheric carbon, since they contain no C and are depleted in C. Releasing radiocarbon-free CO2 to the atmosphere dilutes the atmospheric C content, 3delding lower C/C ratios ("the Suess effect"). From 1850 to 1954 the C/C ratio in the atmosphere decreased by 2.0 to 2.5% (Fig. 11-23) (Suess, 1965 Stuiver and Quay, 1981). Then, this downward trend in C was disrupted by a series of atmospheric nuclear tests. Many large fission explosions set off by the United States with high emission of neutrons took place in 1958 in the atmosphere and the Soviet Union held extensive tests during... 

Figure 2.10 shows the trend in S02 emissions from North America, Europe, the USSR, and Asia from 1970 to 1986 (Hameed and Dignon, 1992). While S02 emissions from North America have decreased significantly, those from Europe have remained about the same and in the USSR have increased somewhat. However, S02 emissions from Asia have increased dramatically due to the increased combustion of fossil fuels, particularly from the use of coal in China and from biomass burning in Southeast Asia (Arndt et al., 1997). For example, Fig. 2.11 shows the 1987 annual emission fluxes of S02 in Asia, where China is seen to be a major source (Akimoto and Narita, 1994). Emissions from ships are also thought to contribute significantly (e.g., Streets et al., 1997 Corbett and Fishbeck, 1997). 

Over the same period, humans released at least 175 billion tons of atmospheric carbon dioxide from fossil-fuel emissions alone. 

According to the global carbon budget by IPCC AR4 report, fossil fuels emission was 7.2 GtonC/y and the atmospheric increase was 4.1 GtonC/y in 2000-2005. The biomass nuclear process removes about 4.9 GtonC/y from atmosphere in the long term, so it will eventually decrease the atmospheric C02 concentration. 

The future environmental implications of a potential large-scale hydrogen economy will depend on how much hydrogen we use, how it is produced, how fast our use increases, the amount of fossil-fuel emissions that can be saved, and the steps we take to control hydrogen emissions. The present atmospheric hydrogen concentration of 0.5 ppmv implies a total mass of about 175 Mtonne of hydrogen, of which around 20% is considered to be from the combustion of fossil fuels. 

Figure 3 Annual emissions of carbon from combustion of fossil fuels and from changes in land use, and the annual increase in atmospheric CO2 (in Pg C) since 1750 (interannual variation in the growth rate of atmospheric CO2 is...

The amount of carbon potentially sequestered is small relative to projected emissions of CO2 from business-as-usual energy practices, and thus the terrestrial options for sequestering carbon should be viewed as temporary, buying time for the development and implementation of longer-lasting measures for reducing fossil fuel emissions (Watson et al, 2000). 

Fig. 7.8 Fossil-fuel emissions and the rate of increase of C02 concentrations in the atmosphere. Vertical arrows define El Nino events (see text for discussion). Data from IPCC (2001). With permission of the Intergovernmental Panel on Climate Change.

Global man-made releases or arsenic into the atmosphere have been estimated by several authors in the past and also more recently. These data were - and still are -divergent as they suffer from large uncertainties due to limited information available. In the first edition of this book, the total anthropogenic As emission per annum was estimated at around 124000 tons, of which about 50000 tons was due to combustion of fossil fuels, mainly from data reported in the late 1970s (Leonard 1991). 

Over the period 1850-2000 it is estimated that 282 Pg C (1 Pg = 1 Gt = 1015 g) were released to the atmosphere by fossil fuel combustion, and an additional 5.5 Pg C from cement manufacture (Figure 22.5). (The 2000 global, fossil-fuel emission estimate of 6.6 Pg C represents a 1.8% increase from 1999. The average annual fossil-fuel release of C02 over the decade 1990 to 1999 was 6.35 Pg C.) In addition, land-use changes are estimated to have resulted in a net transfer of 154 Pg C to the atmosphere since 1850. This totals... 

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