Environmental Impact of Genetically Modified Foods
Malthus once claimed in 1798 that “population, when unchecked, increases in a geometrical ratio. Subsistence increases only in an arithmetical ratio” (Malthus, 1798). By this line of reasoning, the human demand for food should have long outstripped our capacity to obtain it. This is due mostly to technological advances that increase our ability to produce food more efficiently. Some of these advances are mechanical, such as the invention of machines to take the place of animals and reduce human labour, allowing greater areas to be cultivated. Others are methodical, such as the shift from a farm being able to provide a variety of food over the entire year to specializing in one crop each season and using the profit gained by selling the excess crop to obtain a variety in their diet.
More recently, with the discovery of DNA’s structure in the 1950’s leading to the birth of the field of genetics, science has allowed us to manipulate organisms progressively to achieve desirable traits. Although this process has been in place since Mendel’s experiments with peas in the 1850’s, only in the 1990’s were scientists able to insert genes directly and purposefully to affect a target organism. This has led to the creation of many different genetically modified plants that greatly increased our crop yield. However, unlike previous changes to agriculture, genetic modification is much more dangerous due to various factors. Firstly, unlike machines or methodology, which changes how plants are attended to, genetic modification changes the plant themselves. This makes genetic modification much less controllable, for plants are organisms in a biosphere that is capable of reproduction and has many interactions with other organisms. Secondly, cultivation of genetically modified plants is a concept introduced much more rapidly to the industry compared with the other changes. The fact that there is little real-time testing of this new technology, compounded by the fact that the technology itself is a living fragment within a dynamic ecosystem, gives rise to numerous causes of concern caused by genetically modified organisms.
One of these concerns is whether the gene that is modified will travel from its intended organism into the surrounding organisms by a process called gene flow. Gene flow refers to the transfer of genetic material from one organism population into another through pollination or seed movement (Andow and Zahlen, 2005). In general, only the same species can reproduce to create a viable offspring. In plants, however, sometimes crop plants and their wild species are genetically similar enough to be sexually compatible, thus allowing for exchange of genetic material, also known as hybridization, given that they are in proximity to each other so that their pollen can be carried by wind or vectors such as birds or insects. There are a number of species for which this phenomenon has been observed, including rice, corn, cotton, and sugarcane, all of which are important staple cash crops in Africa (Ellstrand et al., 1999). This phenomenon does not necessarily result in environmental consequences, which is instead determined by how the genes between the two species recombine, but knowing the cause of how genes escape our target organisms and end up in wild ones is important to finding better solutions for this problem.
A problem caused by gene flow is the creation of more resistant weeds. The first concern is that genetically modified crops might themselves become weeds and invade its ecosystem. However, this is not a major concern because most crops such as cotton, maize, and soybean have been selected by humans for thousands of years on agronomic sites and have lost most of their weedy characteristics; very few crops are considered weeds outside of their cultivation areas (Hancock and Hokanson, 2004; Hancock, 2003). The second and more important concern is that genes inserted into crops are introduced to weeds via hybridization and; thus, their competitive ability with other plants. The fear stems from the fact that, suppose gene X was added to a crop to make it resistant to a certain herbicide, allowing the farmer to use the herbicide liberally to eradicate weeds without killing his own crops. If hybridization of gene X occurs between the crop and the weeds; however, there is a chance that the weeds will also have gene X in their genome, causing them to be resistant to the herbicide. For example, in Canada, studies have revealed the presence of oilseed rape plants that had become tolerant to three different herbicides following hybridization with genetically modified herbicide tolerant varieties, resulting in increased farm management burdens and a loss of profit (Dale et al., 2002).
Yet another consequence of genetic manipulation of plants is the possibility of unforeseeable effects to non-target organisms. For instance, some agriculturalists believe that it is more effective to insert a gene into a plant to allow them to grow a certain toxin within the plant body to exterminate insect pests, as opposed to employing pesticides that can have negative downstream effects. While this logic is infallible, sometimes one fails to consider other organisms that might also be sensitive to this toxin. These organisms “fulfill important ecological functions such as biological control, pollination and decomposition” (Romeis et al., 2008) and include, but are not restricted to, pollinators, natural predators of the target pest, soil organisms, and herbivores (Craig et al, 2008). One such toxin is known as the Bt toxin. Although that toxin has been extensively researched and appears to be environmentally safe (Thomson, 2007), new toxins used in the future must also undergo rigorous field testing to ensure environmental safety.
Lastly, due to our current agricultural system’s focus on high efficiency, farmers have to grow one species of a certain crop in order to maximize their capital gain. This drastically decreases the biodiversity of our planet, which refers to “the variability among living organisms from all sources [... and] includes diversity within species, between species, and of ecosystems” (Convention of Biological Diversity, 1992), and can cause a replacement of traditional varieties in large regions. For instance, commercial wheat grown in Canada and the United States is all one species and covers a vast area. Extinction of wild species could occur if such high numbers of fertile hybrids are formed that ultimately replace the pure native types. While so far there have been no reports of the extinction of a whole species, there have been instances where hybridization has resulted in the extinction of local populations (Ellstrand et al., 1999). This could lead to economic trouble. A historical example would be the Irish Potato Famine, a time during which potato blight wiped out all potato crops in Europe causing a famine and leading to the death of at a million people in Ireland (Ross, 2002). A similar plight may occur to the current agricultural system because a disease will universally afflict our crops, being of the same species, while there is no plan installed should such an epidemic occur.
One example of a problematic genetically modified plant is the papaya. Genetically modified papaya has viral capsid genes, which are meant to protect it from the ring spot virus that is instrumental in destroying the papaya plants (Ackerman, 2002) and can be grown together with the naturally growing papaya plants and can cross pollinate, meeting the first criterion for gene flow to occur. Research reveals that the genetically modified papaya could pose immense environmental conditions especially when grown alongside the naturally planted papaya plants.
The viral capsid genes in the genetically modified papaya could make the plant a weed and interfere with the growth of the surrounding papaya plants. Research has established that genetically modified papaya interferes with the surrounding plants’ normal growth through competing with them for the available resources as a weed. In addition, assertions have been made that the viral capsid genes could be transferred to the nearest papaya plants causing them to develop into weeds (National Research Council, 2002). This is an enormous environmental hazard, as the weeds do not provide safe, environmental conditions for the growth of other plants. The plants end up not producing the required papaya fruits. The gene transferred to the naturally growing papaya makes them be easily affected by the ring spot virus. This is because the gene comes into these other plants in a more virulent manner, not as a shield but a supporter of virus infection.
These effects of the genetically modified papaya generally have adverse effects on the food industry. UNEP reports that genetically modified papaya causes the death of the naturally growing plants meaning the food industry is going to lose enormously (UNEP, 2008). The food industry is thus likely to encourage the consumption of other foods that could act as a substitute to papaya due to shortages. For instance, research asserts that the food industry could lose up to $30000 dollars in every six months due to the effect of these genetically modified crops. This thus hinders the general food supplies in the countries specializing in the use of the genetically modified papaya.
In conclusion, the scientific developments in alternative means of food production have brought up mixed effects. Most plants can now be produced through the modification of their genes. They are commonly known as genetically modified foods. A gene is introduced into the plant to make it more resistant to viruses or grow at a faster rate. The genetically modified plants could be planted together with the naturally growing plants. The genes in these plants are thus transferred to the naturally existing plants through processes such as pollination. This process is referred to as gene flow. The in the genetically modified plants make some of them to grow onto weeds. The transfer of genes into the other plants could also make them grow into weeds thus posing great environmental problems. The weeds compete for the available resources leading to reduced production. The genetically modified papaya is one of such examples of plants that pose these environmental problems. Genetically modified plants should be encouraged but the environmental problems arising from their adoption should be mitigated to ensure there is increased food supply in the entire world.