Dr. MaquivarAnimal Science 101 Section 3
November 14th, 2018
Effect of Animal Farms on Global Warming
It’s believed that global warming may be caused by the presence of elevated levels of greenhouse gases (GHGs) in the atmosphere. The increased levels of GHGs cause radiation from the sun to essentially get trapped and build up in the Earth’s atmosphere, resulting in a gradual increase in planetary temperature over time. This would eventually lead to changes in weather patterns, an increase in earth’s surface temperature, ocean levels rising, and many other possible worldwide effects. As the climate continues to change it would eventually affect worldwide livestock production by limiting natural resources, a reduction in feed quality and available quantity due to weather changes, an increase in disease and heat related stress, as well as many other possible agricultural consequences (Roja-Downing et al., 2017).
The three primary GHGs emissions produced by the livestock industry are carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) (Zervas and Tsiplakou, 2012). These emissions can be produced directly such as CH4 being produced through enteric fermentation in ruminants, or indirectly through things like transportation or processing and finishing of products (Rojas-Downing et al., 2017). According to Zervas and Tsiplakou (2012), while worldwide agricultural emissions only contribute approximately 10% to 12% of overall anthropogenic or manmade GHGs, livestock related GHGs account for an estimated 80% of those emissions. Ruminants produce the greatest amount of CH4 as a result of enteric fermentation; making up an estimated 30% to 40% of overall livestock emissions. CH4 is particularly detrimental to climate change as it traps heat in the atmosphere at a rate 28 times that of CO2; meaning that the livestock industry greatly effects climate change (Win, 2018).
In many places, particularly developing countries, manure plays an important role in nutrition cycling and is used to maintain soil fertility for mixed crop-livestock agricultural systems (Wanapat et al., 2015). However, manure is also an important contributing factor to GHG emissions and the way in which it’s managed can result in varying levels of N2O and CH4 being produced. In mixed crop-livestock systems that utilize applied manure techniques N2O emissions can be up to 40% higher than emissions from livestock excretions deposited and left in a pasture (Rojas-Downing et al., 2017). By comparison, intensive animal production systems have proven to be able to produce N2O at rates up to 90% less than those produced by mixed crop-livestock systems (Rojas-Downing et al., 2017). The way in which manure is stored and treated also affects the levels of GHGs produced. Manure stored using a dry waste-handling system is more likely to produce higher emissions of N2O whereas manure stored using a liquid waste-handling system is more likely to produce higher emissions of CH4 (Zervas and Tsiplakou, 2012).
Livestock are an important global commodity. Because of the inherent nutritional value animal products are experiencing an increasing amount of demand especially in developing countries. The livestock industry provides jobs for approximately 1.1 billion people worldwide (Rojas-Downing et al., 2017). According to Rojas-Downing et al. (2017), there will be an estimated increase of overall worldwide demand for animal products by approximately 70% by the year 2050. Because of the relation of GHGs to enteric fermentation and as a byproduct of transportation, feed production and other indirect means related to the livestock industry there can then be an anticipated associated rise in GHGs in direct correlation to an increase in livestock production. This necessitates the importance of the implementation of strategies to mitigate overall GHG emissions in relation to the livestock industry.
The increasing demand for animal products has resulted in an increasing effect of animal farms on global warming. The rise in demand results in an increase of greenhouse gas emissions, directly through the increase in numbers of required livestock and indirectly through the increased release of GHGs relating to the livestock industry. Ruminants specifically are a significant source of methane emissions, a particularly detrimental GHG in regards to its effects on climate change (Win, 2018). The effects of global warming could in turn have consequences resulting in dire effects to the livestock industry (Rojas-Downing et al., 2017). This results in the need and direct motivation for steps to be taken to mitigate emissions through out the industry.
While work has already been done to help mitigate livestock related GHGs there is still a need for improvement. Changes to feed and ruminant diets, as well as breeding for increased feed efficiency and productivity could result in significant decreases of direct livestock emissions (Llonch et al., 2017). Better overall management of manure, as well as changes to feed production practices could drastically reduce the amount of GHG emissions indirectly relating to livestock (Rojas-Downing et al., 2017).
ReferencesScientific, peer-reviewed journal articles
Llonch. P., Haskell, M.J., Dewhurst, R.J., and Turner, S.P. (2017). Current available strategies to mitigate greenhouse gas emissions in livestock systems: an animal welfare perspective. Animal. 11(2): 274-284. https://doi.org/10.1017/S1751731116001440Rojas-Downing, M. M., Nejadhashemi, A. P., Harrigan, T., and Woznicki, S. A. (2017). Climate change and livestock: Impacts, adaptation, and mitigation. Climate Risk Management. 16: 145-163. https://doi.org/10.1016/j.crm.2017.02.001Wanapat, M., Cherdthong, A., Phesatcha, K., and Kang, S. (2015). Dietary sources and their effects on animal production and environmental sustainability. Animal Nutrition. 1(3): 96-103. https://dx.doi.org/10.1016%2Fj.aninu.2015.07.004Zervas, G., and Tsiplakou, E. (2012). An assessment of GHG emissions from small ruminants in comparison with GHG emissions from large ruminants and monogastric livestock. Atmospheric Enviroment. 49: 13-23. https://doi.org/10.1016/j.atmosenv.2011.11.039Popular press
Win, T. L. (2018). Fighting global warming one cow beltch at a time. Reuters.com. July 19, 2018