Superweeds are weeds that cannot be killed with the usual pesticides used by by today’s agro-businesses, such as Roundup. They have begun to pop up in fields that grow crops which have been genetically modified (GMO) to increase their resistance to pesticides. This allows farmers to use Roundup more liberally to kill weeds. This approach worked very well at first, but after a prolonged overexposure of the weed population to Roundup, weed species resistant to Roundup have been selected. This is a serious agricultural problem, as these weeds lower the yield, increase the cost of harvest, and remain a problem that is not easily solved.
Why is this strategy employed, when agronomists predicted that such an outcome was inevitable? Why not just move to organic farming, eliminating the use of chemical pesticides, which like antibiotics, are indiscriminate in destroying both pests and beneficial organisms?
The context is sustainable agriculture and global food security. The old Malthusian concern about the world eventually running out of food for a rapidly growing world population has not disappeared. The solution at the advent of the Industrial Revolution, Malthus’ time, was to apply technology to increase the food supply. As the population has increased many times since Malthus, the world has seen the scientific and technological approach to the increase of the food supply work wonders. But as the population has continued to expand, more radical methods have been used to increase the food supply that are not sustainable in the long term.
The amount of arable land is limited, and in fact shrinking, and most of it is in use today; water suitable for agriculture is limited and shrinking due to overuse; and human-generated pollution has been a factor in both cases, much of the pollution coming from unintended effects of heavy use of pesticides and fertilizer; many major rivers no longer flow all the way to ocean, with every drop of available fresh water in their watersheds being diverted for human consumption. The heavy use of fossil fuels necessary for industrial farming further complicates the picture, polluting the air and consuming a limited resource. These are profound issues, and there are no simple answers to them.
Organic farming, defined here as foregoing the use of chemical pesticides and fertilizers, would go a long way towards resolving the polluting side-effects of those agents, but the cost is considerable: This approach produces a much lower yield at a much higher cost, to the degree that completely removing the use of chemical pesticides and fertilizers would threaten food security for the current human population, the nightmare described so long ago by Malthus, where the global human population size has outstripped the capacity of humans to provide food for sustenance.
Opponents to GMO crops have produced a video that provides an excellent description of the growing proliferation of superweeds, and the agricultural approach which has allowed their proliferation, but the video’s emphasis on the role of genetically modified crops is misplaced.
Insufficient crop rotation and overuse of pesticides, particularly use of only a single pesticide, is more prevalent in agriculture today, and increases selection pressure for superweeds, and does so whether the crops involved are GMO or not.
The more accepted methods of pesticide usage today is to utilize several different pesticides in smaller and varying amounts on the same field, and to continue to rotate crop types; this lowers the chance of selecting for pesticide resistance, lowers the requirement for manufactured fertilizers, and minimizes the requirement for destructive plowing and tilling.
GMO crop opponents would have a valid concern if the superweeds were to be shown to have the Roundup resistance gene that was added to the GMO crops, but no GMO crop or other GMO organisms (like yeast and bacteria genetically modified to produce human insulin, for example) have been found to have spread their modified genes outside of their own gene pools, and particularly have not been found to have spread those genes across species, although there are ongoing studies, as there should be, to monitor the potential spread of these genes. More directly to the point, billions of meals have been consumed which contain GMO foods, and there has been no known issue.
There has been a good deal of hysteria from green advocates that is not backed by good science;, nutritionally superior GMO crops (Golden rice, etc.) are being rejected in the places that could use them the most: China and India. Europe, a bastion of educated citizens, is almost GMO-free. This unfortunate: the desire of many anti-GMO advocates is to make the world a better place, but it may be asked, for whom?
Current agricultural methods are not sustainable in the long term, yet without them global food security is seriously threatened. For our food supply, the conundrum today and for the long term is three-fold: It would appear that we cannot together have sustainable agriculture, global food security and an ever increasing human population, that these outcomes are to a degree mutually exclusive.
It is clear that something has to give, but future efforts to provide global food security and sustainable agriculture must include continued efforts to slow or halt population growth, and a continued search for technological improvements that are less damaging and produce higher agricultural yields using limited resources. GMO crops are a critical biotechnological tool in that effort, so far a demonstrably safer alternative than traditional plant breeding, and will continue to offer a more refined means of doing what traditional breeding has done: to modify plants that will provide us with higher yields, shorter life cycles, that will require fewer resources, land and/or water to grow, etc. By themselves, however, they do not offer complete solutions to the environmental constraints that land, water and chemical overuse pose. Specifically, the compromised agronomy that increases the threat of superweeds is neither caused by GMO techniques nor solved by them.
For a more complete and detailed discussion of the larger issues and GMO crop’s role in those issues, read this article: Plant Genetics, Sustainable Agriculture and Global Food Security.
A recent and more compact discussion of concerns regarding GMO crops can be found in Nature (via a Scientific American reprint).
Thanks to my sister-in-law, Shelby, who recommended that I watch the superweeds video.