Abstract
The U.S. population has grown from ~40 million in 1870 to over 300 million today. To meet the demands of a growing population, agriculture has seen the rise of technological advances including the tractor, hybridization, agrochemicals, and genetic engineering. Improved methods leading to excess yields from agriculture have has major environmental impacts. Agriculture produces up to 30% of greenhouse gas (GHG) emissions in developed countries (Clark and Tilman, 2017; Hallström et al., 2015; Klein et al., 2014), accounts for more than 70% of global freshwater use (Clark and Tilman, 2017; Jalava et al., 2014), and uses 30% of available global energy (Food and Agriculture Organization of the United Nations, 2012). Additionally, agricultural chemicals degrade up to 7 million hectares of arable land per year (Maredia and Pingali, 2001), decommission aquatic breeding grounds, and significantly reduce species biodiversity. Increasing efficiency and crop yield from agricultural technologies have created a surplus of certain commodity crops. These surplus crops are refined into cheap, energy-dense foods that provide excess calories. Excessive caloric intake is the major contributor to the more than three-fold increase in adult obesity in the U.S. since 1960. Obesity increases food energy demands by 19% (Mann, 2017) and transportation fuel consumption by nearly 2% (Tom et al., 2014). With nearly 40% of U.S. adults classified as obese (Hales et al., 2017), the environmental impacts of a population growing in both number and weight is considered in this thesis.
