The Impacts of Climate Change on United States Agriculture

 

(Drip Irrigation)

Ryan MacMullan- Plant and Soils Science Major, Jonevan Pomeroy- Building Construction and Technology Major, Austin Ford- Forestry Major

 

Between 1910-1930, farmers were pressured to plow millions of acres of grassland in the Great Plains as a result of World War I and an increased food demand for soldiers and their families (History, 2009a). Advanced agricultural practices such as crop rotations and genetically engineered crops weren’t yet applied to the crops, and farming practices revolved around surface irrigation which relies upon precipitation and the natural flow of water to their crops via channels dug into the earth and only had water use efficiencies of 50-70% (History, 2009a; Bjorneberg, 2013, p. 2). This was done without the knowledge of the environmental consequences and in a desperate attempt to meet the food demands of war. (Lee & Gill, 2015). The slogan “the rain follows the plow” was a common phrase that farmers used in hopes of a plentiful crop season (Lee & Gill, 2015). However, this saying was incredibly far from the truth and their excessive plowing and wasteful irrigation practices actually resulted in decreased agricultural yields and disruption to the environment.

Prior to the 1950’s, crop irrigation was virtually a non-practice in the United States in comparison to what it is today (Anderson, 2018). The vast majority was surface irrigation which relied upon the diverted water from natural rivers and streams to seasonally supply their fields with rainwater and snowmelt (Anderson, 2018; Bjorneberg, 2013). Towards the beginning of the 20th century, very expensive well pumps became available for the most affluent of farmers, but were a rather scarcity and incapable of delivering sufficient water to a large scale farm (Anderson, 2018). The trouble was that the water was too deep to be reached, “sequestered between rock, gravel, and clay in a vast underground reservoir now known as the Ogallala Aquifer” (Anderson, 2018, para. 5). The labor and costs to build such a well and install the piping were too great for the vast majority of American farmers (Anderson, 2018). Farmers were left without groundwater irrigation techniques, and they relied heavily on seasonal rains to provide them with the water their crops needed. Then drought hit. “There were four waves of droughts [in between 1930 and 1940], one right after another… But it felt like one long drought” (Amadeo, 2019, “Timeline”). Between 30 and 50 percent of crops across the country failed, and many farmers could not produce enough food to eat (Amadeo, 2019, “Timeline”).

Despite years of low crop yields and dry, nutrient-deficient soils, farmers continued to plow their soil in hopes of growing healthy, nutritious crops to feed their families and meet the demands of the war (Lee & Gill, 2015). Plowing is typically used to conserve rainwater and reduce soil loss from surface erosion; however, when dry topsoil is plowed, the soil remains loose and becomes more susceptible to erosion (Lee & Gill, 2015).  In 1931, a combination of the worst droughts in US history at the time, increased temperatures, and millions of acres of dry, nutrient-deficient farm land created the perfect conditions for dust storms in what is otherwise known as the Dust Bowl era (Nelson, 2010). Massive walls of soil and dust known as “black blizzards” hindered all sunlight for days, and carried topsoil from the Great Plains to as far east as New York City (History, 2009a). As a result of these inhospitable conditions, the Dust Bowl is responsible for the largest migration in American history as more than 2.5 million people left the dust bowl states of Texas, New Mexico, Colorado, Nebraska, Kansas, and Oklahoma (History, 2009a). A combination of infertile soil and lack of food left millions of people in or on the brink of poverty (History, 2009a).

The only escape from the Dust Bowl occured when, in 1941, rainfall levels had finally returned to normal. Farmers were then, and still today, incredibly dependent on rainwater to supply their crops. Between the 1950s and the 1980s, tens of thousands of wells connecting to sprinkler irrigation systems were created and sunken into the Ogallala Aquifer (Anderson, 2018, para. 12) This created a secondary source of water for American farmers, one which could be relied upon during periods of drought, but which still ultimately relies on rainwater in order to be recharged (Amadeo, 2019). Today, 54% of American farms rely on sprinkler irrigation, 7% on an even more advanced micro irrigation system, while the remaining 49% either uses surface irrigation or no irrigation at all (Bjorneberg, 2013, p. 1). All of these irrigation methods, with the exception of the very few no-irrigation farms, rely on some sort of well water tapping into the very finite aquifer (Amadeo, 2019). This recent development has resulted in the Ogallala Aquifer water being depleted eight times faster than the rain is putting it back (Amadeo, 2019, “How it could happen again”). Our aquifers will be depleted eventually if we do not alter our practices, risking the re emergence of the Dust Bowl.

As a result of the devastation of the Dust Bowl, government programs were instituted to change agricultural practices and have helped to prevent such a disaster from reoccurring. President Franklin D. Roosevelt took a number of measures to help alleviate the suffering of the displaced farmers (History, 2009b). Roosevelt established the New Deal Program which had many consequences, but the most important was the $52.5 million sent to provide drought-aid, livestock feed, and proper equipment to farmers and businesses directly affected by the Dust Bowl (History, 2009b). The plan also funded research into better land-management practices and set up government-regulated markets for farm products (History, 2009b). However, despite our altered practices, climate change is setting the stage for another agricultural catastrophe on an even greater scale. If we have any hope of preventing this, we must learn from history’s mistakes, and take preemptive action in the form of government regulation and genetically modified crops to conserve water and make more sustainable farming practices more affordable to average American farmers.

In recent years, climate models have predicted increased temperatures during the next half century which will dry out the soil and minimize the amount of plant available water (Lieberman, 2015). Plant available water is the total amount of water in the soil which the plant is able to consume, but does not refer to the total amount of water in the soil (Campbell, n.d.) Evapotranspiration is the main driving force of water consumption in agriculture, and is the combination of evaporation from the soil surface with evaporation through plant tissues, the later better known as transpiration (Schwalbe, n.d.). Rising temperatures of between 3.4℃ and 6.7℃ will boost evapotranspiration rates and thus result in drier soils (Lieberman, 2015; Lychuk, Hill, Izaurralde, Momen, & Thomson, 2017, p.228). These rising temperatures will cause conventional agricultural plants run on overdrive, rapidly burning through their reserves of water and energy, leading the decreased yields and rising demands for water. Evapotranspiration rates are predicted to increase by as much as 25%, and groundwater recharge (the rate that water absorbs back into the ground) will decrease by a staggering 98%. The decrease in plant available water in conjunction with rising temperatures and evapotranspiration rates will significantly increase the demand for irrigation (Weinhold, Vigil, Hendrickson, & Derner, 2017, p. 221; Stambaugh, Stroh, Whittier, Struckhoff, & Guyette, 2018, p.622). As climate change worsens, crops will consume freshwater more quickly and the demand for irrigation will continue to expand unsustainably.  

Climate change will directly affect the availability of water for crop irrigation in the US which will ultimately reduce crop yields. With a rise in average temperatures, the amount and duration of droughts in the US will be directly affected (Stambaugh et al., 2019). Although overall mid-century precipitation is actually predicted to increase, it is forecasted that the majority of this precipitation will be in the form of heavy rainfall events, and much less of it will fall as snow (Weinhold et al., 2018). Snowpack retains a very high percentage of precipitation, and melting snow is responsible for fueling many rivers, lakes, and aquifers. Without snowpack, much of the precipitation will simply be inaccessible for agriculture because the rate of precipitation during heavy rainfall can exceed the infiltration rate of the soil (the maximum rate at which water can flow into the soil), resulting in a large percentage of the water being lost as runoff as it rapidly flows downstream (Weinhold et al., 2018). Not only will this water be unavailable for farmers, but it will also be moving too quickly over the land to embed itself into the aquifer. With freshwater widely inaccessible, farmers will have no choice but to hope for the best and continue pumping water out of the aquifer at a dangerous pace.

The Ogallala aquifer on its own provides 27% of the irrigation water for U.S. crops (Lauffenburger et al., 2018, p.71). Aquifers account for roughly 50% of irrigated water in the present day, up from nearly 20% in 1950 (United States Geological Survey, n.d.a,“Irrigation”). Annual crop yields in the northwest will require nearly 5% more irrigation as soon as 2030 (Rajagopalan et al., 2018, p.2164). Across the entire United States Agriculture system, an 5% increase in water demand annually would result in 156 billion gallons of additional water, or an additional 2% of the Ogallala aquifer’s total capacity lost per year (United States Geological Survey, n.d.b; Mission 2012: Clean water, n.d.). To put this into even simpler terms, it would account for an additional amount of water the size of 200 empire state buildings, every single day, 365 days a year (USGS, n.d.b; Conners, n.d). If we continue at this pace, we will very soon deplete many of the aquifers around our country, destroying the very thing which has been responsible for preventing another Dust Bowl era.

While an event exactly like the Dust Bowl might not occur again, climate change will significantly impact farmers crop yields in the same way as the Dust Bowl (Lychuk et al., 2017, p. 1). Fewer water resources, less dependable precipitation, and higher rates of evapotranspiration all will increase the likeliness of decimated agriculture and a resulting food shortage. Although irrigation practices are more reliable today than they were during the 1930’s, they still rely on a certain amount of water from precipitation and for sufficiently supplied aquifers (Lauffenburger et al., 2017). Increases in irrigation efficiency will be met with high costs, as most American farmers are already using advanced methods of irrigation known as sprinkler irrigation, with efficiencies between 60 and 95% (Bjorneberg, 2013, p. 2). Further upgrades would incur even greater expense with even fewer rewards; the transition to micro irrigation would only improve efficiency to between 80 and 95% (Bjorneberg, 2013, p. 2). The price of this improvement would be between 800 and 1200 dollars per acre, with additional maintenance and operation costs varying based on location (On farm water delivery systems, 2004,“Cost-effectiveness considerations”). With the predicted decline of usable precipitation and freshwater resources, American farmers will have to look towards other viable solutions besides improvements in irrigation to combat climate change and to meet the food demands of the nation.

In order to combat the decrease in freshwater availability, American farmers must choose corn varieties better adapted to the hotter and drier climate. As drought conditions worsen, the benefits of improved crop irrigation through more advanced practices tend to be outweighed by the ever increasing expense of the technology (Malek, 2018). Thus combatting worse drought conditions and higher temperatures will need to rely more heavily on the introduction of drought and heat tolerant plants as opposed to improvements in irrigation (Way, Katul, Manzoni, Vico, 2014). Scientists have found a way to transfer a water-saving and heat-tolerant ability, known as C4 photosynthesis, into common agriculture plants (Sage & Zhu, 2011). This scientific revolution will help farmers to deal with a lower amount of available freshwater at a fraction of the cost of improving irrigation practices.

Genetically modified crops will drastically reduce the water demands of American agriculture while preserving nutritional value, improving plant stress tolerance, and saving the farmers money. These traits will be essential for improving and preserving our agricultural yields through the predicted effects of climate change. Genetically modified organisms have had the characteristics of another organism copied and pasted into their genetic code (World Health Organization, 2017). In simpler terms, scientists simply take the DNA out of one plant and put it into the other, thereby transferring specific traits from one species into another. For the purposes of this paper, GMO crops are synonymous with C4 crops, and conventional crops are synonymous with C3 crops. C4 plants have an advanced method of photosynthesis which enables them to operate under hot and dry conditions that C3 plants cannot tolerate (InTeGrate, n.d.). Under the same conditions, C3 plants start to run on overdrive (Sage & Zhu, 2011). This causes them to quickly deplete their sources of fuel, produce self-harming toxins, and rapidly burn through their reserves of water (Sage & Zhu, 2011). GMO plants are able to take advantage of these extreme conditions, while at the same time consuming less than one-third the amount of water as their conventional counterparts (Way et al., 2014). GMO crops are also far more affordable than increases in irrigation technology, with seeds going for about $100 per acre, although historically they have been only around $20 per acre (Schnitkey, 2017). This rise in price has been due to companies owning the rights to GMO crops, and is something which needs checked through government regulation. Although introducing new irrigation techniques may seem like a good alternative to introducing GMO crops, the environment simply will be far better suited to GMOs than conventional crops, and the price of improved irrigation will reap few rewards. GMOs will be able to thrive with no additional improvements to irrigation technology, saving farmers huge amounts of money.

Along with being drought resistant, GMO’s actually outcompete conventional crops in terms of yield. Since the introduction of GMOs, the United States has been one of the leading countries in growing and studying drought-resistant GMO crops (Jacobsen, Sørensen, Pedersen, & Weiner, 2013). In a study of 168 data sets throughout the US and Canada, comparing yields of various GMO crops to conventional crops, 74% indicated an increased yield of GMO crops,  19% indicated no difference, while only 8% indicated decreased crop yields (Jacobsen et al., 2013). Although the evidence for the effectiveness of GMO crops is convincing, the main limiting factors preventing farmers from switching to GMOs are a lack of seed price regulation as well as fear of lawsuits targeting the farmers for unauthorized use of the proprietary seeds.

Returning to the drama surrounding the Dust Bowl, President Franklin D. Roosevelt took a number of measures to help alleviate the suffering of the displaced farmers (History, 2009b). Roosevelt established the New Deal Program which had many consequences, but the most important was the $52.5 million sent to provide drought-aid, livestock feed, and proper equipment to farmers and businesses directly affected by the Dust Bowl (History, 2009b). The plan also importantly funded research into better land-management practices and set up government-regulated markets for farm products (History, 2009b).

Similar to the solution for the Dust Bowl, farmers need government intervention. This intervention needs to be in the form of price regulation, grants, and the de-privatization of genetics. One of the main reasons farmers aren’t already using GMO varieties that are more efficient is because of the high cost of seeds in recent years (Royte, 2013). GMO corn seeds can cost $100 or more per acre than conventional corn (Royte, 2013). Since the ability to patent GMO seed varieties in the 1980s, seed prices for GM crops have skyrocketed. A USDA study found that, between 1995 and 2014, per-acre costs corn seeds had risen by 500% (Schnitkey, 2017). This is due to 80% of corn seeds being owned by the four large corporations: Monsanto, DuPont, Syngenta, and Dow (Farm Aid, 2016). On top of this, the companies that own the rights to the GMO seeds force small scale farmers to pay royalties and other fees for using their product, accruing even more costs (Charles, 2012). As a solution, we propose that the USDA limit the initial cost and royalties being paid to large seed companies for use of their GM varieties to allow all farms the chance to afford these seeds. This will allow widespread use of GMO crops across the country that will be able to readily adapt to climate changes in the coming years. These small scale farms are also important because it will provide local communities around the farms with a supply of locally grown, GMO crops.

Along with the high prices of GMO seeds, there are many negative stigmas revolving around the health benefits of GMO crops. Many family farmers and US citizens are opposed to GMO crops, as they are seen as bad for the environment, and detrimental to consumers health. With websites like the “Non GMO Project,” consumers are lead to believe that GMO’s are bad for the environment and bad for human health (Bennett, 2015). GMO’s have also been accused of creating unwanted changes in nutritional content along with the creation of allergens and toxic effects on bodily organs (Brody, 2018). GMOs have also been labeled as carcinogens, allergens, and contaminants of organic food crops (Bennett, 2015). These accusations all play a factor in farmer’s minds when they decide whether or not to use GMO. (Of course, none of these have been proven). To counter this argument, GMOs actually provide the same health benefits and more than conventional crops do (Renee, 2015). GMO’s are developed with enhanced nutritional content to benefit the health of the consumer (Renee, 2015). They are also modified to enhance certain nutrients like polyunsaturated fats, which play a role in protecting against heart disease (Renee, 2015). Other GMO foods are healthier because they are modified to introduce vitamins such as an introduction of beta-carotene into rice to help combat vitamin deficiencies in affected communities (American Society of Animal Science, 2012).

In the end, the facts have been published to the general public pertaining to climate change, the depletion of water resources, as well as the pros and cons of GMO’s. Despite many studies that state climate change is scientifically proven to be true, there will always be a group of people who chose to disagree with the evidence. Similarly, with GMO’s, there will always be a group of people who actively disagree with the use of GMO’s for various reasons. However, despite what these people choose to believe, climate change is actually occurring and will continue to devastate and change the United States as we know it. The increase in temperatures will ultimately deplete natural water resources and have a major impact on the crop yields and available food for American Citizens (Lauffenburger et al., 2018, Lychuk et al., 2015, Stambaugh et al., 2019, and Weinhold et al., 2018). Without a solution like the use of genetically modified crops, the availability of food will be seriously threatened. GMO’s, despite being studied for many years, are still a relatively new concept (Jacobsen et al., 2013). Along with the support from the public and the incentives from the government, we propose that the significant threats to crop yields and food availability will be greatly reduced in the long term.

 

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