*2.1.1 Agricultural soils*

The largest source of GHG emission from Agriculture is Nitrous oxide (N2O) and it accounts for 38% of the total global emission. Through the process of nitrification and denitrification, it is produced naturally from soil. Agricultural activity which is anthropogenic may add nitrogen directly or indirectly to soils. The use of nitrogen fertilizer, production of nitrogen-fixing crops and forages, retention of crop residues, application of managed livestock manure, sewage sludge and cultivation of soils with high organic matter content are the direct additions. Through indirect additions are surface runoff and leaching of applied nitrogen into surface and ground water, volatilization and atmospheric deposition of applied nitrogen [11]. Other anthropogenic sources of GHG emissions from agriculture include manufacture of equipment, pesticides, fertilizers, on-farm use of fuels and the transport of agricultural products [12]. Emissions of GHG from agricultural soils (N2O) and enteric fermentation and management of manure (CH4) linked with livestock production contribute to the largest share in agricultural sector. So, from agricultural sector, sources of GHG emissions are accounted for as follows: Residue burning/forest cleaning (13%), Methane and Nitrous oxide from Management of manure (7%), Methane from Rice cultivation (11%), Nitrous oxide from fertilizers (37%) and Methane from Livestock (32%) [11]. These emissions are expected to increase in future due to high demand for agricultural products and enhanced nutrition [13]. The direct addition of both synthetic and organic nitrogen containing fertilizers will possibly be a key source of rise in emission of N2O with the highest coming from developing countries that are seen using 36 million tons more than the developed nations [14].

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*Impact of Emerging Agricultural Contaminants on Global Warming*

of methane gas could lead to negative climate impact.

*2.1.3 Management of manure*

Climate Change.

6°C within 2021 [4].

from ruminants produced globally are about 80,000 Gg [16].

Emissions from Livestock constitute 9% of CO2 equivalent obtained from all human related activities and produces 65% of human-related nitrous oxide, and 37 percent of human induced methane, and 64% ammonia especially from manure. Considering agriculture sector, livestock account for nearly 80% of all emissions [15]. All these emissions from livestock make it a major target for mitigation options. Feed produced locally such as grass and other roughage, together with wastes that are rich in nutrient from farms and households when replaced with feed manufactured from feed mills containing some secondary plant metabolites able to reduce the emission

The natural digestive processes in ruminants otherwise known as enteric fermentation in sheep and cattle account for the key source of methane production under this category hence the second largest source of total agricultural emission with 34% global share and rice cultivation being the third with 11%. Other domesticated animals that also emit methane (methanogenesis) as a by- product of enteric fermentation include Horses, swine and poultry. The estimates of enteric methane

Handling, treatment and storage (Management of manure) of manure account for 7% of emissions from agriculture. Anaerobic breakdown of manure produces methane (methanogenesis) while aerobic handling of manure produces nitrous oxide (Nitrification) and then anaerobically (denitrification) hence often increased when the available nitrogen exceeds that of plant requirements [12]. Due to high demand expected for beef and dairy products globally especially from the developing world, methane emissions from enteric fermentation are expected to increase by 32% [11].

**3. Impact of emerging agricultural contaminants on global warming**

The three important greenhouse gases (Methane, Carbon dioxide and Nitrous oxide) are not harmful in naturally occurring quantities for their atmospheric presence helps in sustaining life on the planet when they trap heat energy near the surface of the earth. Concentration of greenhouse gases from both the natural and human factors have been increasing and contributing to Global Warming and

Increase in greenhouse gases may cause tremendous changes to our civilization positively or negatively but the total impact is uncertain. Climate change comes as a result of a warming planet which can affect the weather adversely in many ways. So, as climate changes, extreme weather activities release severe threats on human society. Indicators of global warming include ocean heat content, sea ice, sea level, sea surface temperature, temperature over ocean, temperature over land, tropospheric temperature, snow cover on hills, temperature over land and humidity. It is expected that climate change may cause more floods, storms, droughts, heatwaves and other extreme weathers activities. IPCC estimated that temp may rise from 2 to

Industrial Agriculture is one of the causes of climate change with the practices having impact on it. The currently practiced industrial agriculture with Agrochemicals and monocultures globally is a key contributor to climate change for it causes the emission of Green House Gases (GHG) via changes in land use and soil degradation or losses, via technologies in agriculture and from livestock [17].

*DOI: http://dx.doi.org/10.5772/intechopen.94170*

*2.1.2 Livestock*
