The health consequences of genetic modification remain unclear. It is a different story for the environmental consequences. Studies leave no room for doubts: transgenic agriculture and GE animals have harmful repercussions for the environment, especially for biodiversity, and biodiversity is a cornerstone.
Biodiversity refers to the variety of individuals present within a single species, and the greater the biodiversity the higher the species’ likelihood to survive adverse circumstances such as epidemics or climate change. For example, if a species is made up of genetically homogenous individuals and it encounters adverse changes, the species as a whole will be affected, whereas if the species is made up of diverse individuals there are likely to be some who are either not affected, or less affected, and these will survive.
The other kind of biodiversity refers to the multiplicity of species that inhabit a specific ecosystem. The greater the biodiversity, the greater is the health of the ecosystem. When genetically modified organisms are placed in a system, biodiversity, which is already threatened by other human activities, is seriously endangered.
GMOs tend to have an aggressive nature, which makes genetic pollution highly probable. When plant pollen is transported by insects and the wind (and this can happen even over long distances), the genetically modified plants are able to contaminate other vegetable species, including wild species. Cross-pollination with GMOs risks losing the genetic make-ups of plants whose process of evolution can have taken place over thousands of years.
Increased Pesticide Use
Contrary to the view promoted by the supporters of GM, in most cases, use of pesticides has actually increased in transgenic agriculture. A study examining the impacts of transgenic agriculture in the US from 1996 to 2003, found that despite the consumption of pesticides decreasing in the first few years of GMO’s cultivations, it has significantly increased in the following years to the point where the amount of pesticides sprayed on most transgenic crops in the US is higher than the amounts used in the conventional agriculture.
This increased use of pesticides is a result of the nature of the most common variety of GMOs, the herbicide-tolerant plants. Because these GMOs can be sprayed with weed killers without dying, whereas the infesting weeds are killed – this means growers can spray more liberally and more often. This in itself causes an increase in the pesticide/herbicide application.
Where the real problem lies is in the effects of cross-pollination. Through the pollen, GE plants can fertilise other plant species in the nearby areas, with the result of transmitting to them part of the resistance to the herbicide. Growers therefore need to increase the strength of herbicide applications.
The future sees a continued increase in pesticide use not just on weed pests but on insect pests. It is highly probable that there will be a rise in pesticides used for the second variety of GMOs, the Bt-plants which include Bt-corn and Bt-soya. These GMOs have an integrated gene that enables the modified plants to continuously produce a toxin from a bacterium, the Bacillus thuringiensis (Bt). This toxin acts as a pesticide repelling insects that normally attack the plant. Although this works as an insecticide initially, within a few years it will only strengthen the insects to become more resistant and aggressive. This will result in the need to use larger quantities of insecticides.
Genetic pollution from GMOs is a real possibility. This can occur through cross-pollination, unplanned breeding and horizontal gene transfer. These occurrences may result in extensive and unpredictable health, environmental and socio-economic impacts.
Not only can, and do, the GMOs spread through reproduction in plants and animals, the new organisms could also expand themselves through a horizontal transfer of genes. The genetic hereditary material inserted into the organism’s DNA and expelled by it because of its high instability, can be assimilated by other organisms, eg soil bacteria, that in turn are able to transmit it to other organisms such as vegetables and humans.
Pollution from GMOs represents an irreversible kind of pollution. Unlike other pollution that can be eradicated or minimised eg fossil fuel pollution, once the genetically modified organisms are released into the environment, they trigger reactions that are irreversible.
Gene Transfer into Bees
A study undertaken at the Institute for Bee Research, University of Jena found a gene transfer from genetically engineered rapeseed to bacteria and fungi in the gut of honey bees. These results show the crossover of genes takes place on a greater scale than previously assumed. They also indicate that these changes may take place in the intestinal tubes of people and animals as well, which results in the microorganism makeup in the intestinal tract being changed. This can therefore have health consequences. The potential threats to bee species could have massive consequences for the environment. Bees are a keystone species that pollinate numerous species, in fact, some plant species are only pollinated by one species of bee. Threats to bees could result in mass local extinctions. This highlights the unknown effects that GE can have through the complex interlinked ecosystem where feedback loops could produce catastrophic effects.