Dear Friends and Colleagues
We are in the Anthropocene and likely experiencing the Earth’s sixth mass extinction, the first to be caused by humans. In 1962, Rachel Carson warned in her book, 'Silent Spring' that the decline of birds (primarily due to DDT exposure) was a warning of environmental collapse and that human health was intricately tied to environmental health. Extinction rates have increased continuously over the last 100 years. The loss is exemplified by amphibians, a vertebrate class that survived the last four mass extinctions. As much as 70% of all amphibian species are threatened globally.
Chemical contaminants in the environment are playing an important role in the Anthropocene. Over 85,000 synthetic chemicals exist today, and can end up in the environment. Over the last 75 years, the use of pesticides has increased dramatically and continues to increase. Approximately 2.3 billion kilograms of pesticides are used annually worldwide, largely in agriculture.
A recent journal paper reviews evidence that pesticides have altered the gene pool of target organisms and through direct toxic effects and so-called “low dose” effects (effects below concentrations considered safe) have altered landscapes and populations globally. It states that there is virtually no habitat or organism that is now free from pesticide exposure or effects. It cites clear evidence that increasing pesticide applications increases the evolution of resistance and increases the widespread low-level contamination that leads to endocrine disruption and transgenerational effects.
The authors warn that several interactions between changes associated with the Anthropocene and pesticides will inevitably result in collapse if not mitigated: Climate change is increasing the development and evolution of resistance to herbicides and likely insecticides, increased use of pesticides (in response) will increase the number of resistant pests, increased pesticide use will exacerbate the damage, resulting in more resistance weed species which will decrease productivity and more resistant insects which will both decrease crop yields and increase the spread of vector-borne diseases.
The authors warn that the production of GMO crops has increased and will continue to increase the use of pesticides, in particular, herbicides. The paper concludes that the intertwining of the chemical industry and the seed industry is at the heart of the problem. The financial incentive to generate pesticide resistant crops (or chemically dependent agriculture) is driving the increased use of chemical pesticides. An integrated pest management (IPM) approach, on the other hand, seeks to reduce yield loss to an economically acceptable level and limit damage to the environment by chemical practices. The increased use of GMO technology to produce crops that require pesticide application will continue to limit the ability to use an IPM approach. The solution put forward is to decouple the seed industry and the pesticide industry (a regulatory ruling to require the separation of the chemical industry and seed industry) and to provide incentives to growers to use less and fewer chemical pesticides. This is cited as the only way to avoid more widespread damage due to overuse of pesticides.
With best wishes,
FROM SILENT SPRING TO SILENT NIGHT: AGROCHEMICALS AND THE ANTHROPOCENE
T. B., & Hansen, M. (2017). Elem Sci Anth, 5.
We are now living in the Anthropocene, the first time in Earth’s history when synthetic chemicals—created by humans—are damaging the planet and contributing to a major loss of biodiversity. Pesticides are a particular problem in this regard. Agricultural practices changed dramatically following World War II. Methods for the production of nitrogen for manufacturing explosives were adapted for use as fertilizer in agriculture. Further, chemicals used to combat insect vectors for disease during World War II were adapted for the control of insect pests in agriculture. Eventually, herbicides used as defoliants to destroy food supplies and aid in combating soldiers using forests as cover, were customized to control weeds in agriculture. The heavy use of pesticides in agriculture has resulted in global exposure to these chemicals. Travelling through water, air, and in migrating animals, pesticides can be found in drinking water reservoirs, the atmosphere, on mountain tops, and even in remote areas in the Arctic where they are not used. The widespread exposure to agrichemicals has altered landscapes and ecosystems around the world. In addition to directly killing non-target organisms, target and non-target organisms can evolve resistance to pesticides, resulting in altered gene pools. Further, emerging data demonstrate that even low— formerly considered “non-toxic”— concentrations of pesticides can impact health, physiology, reproduction and development through endocrine-disrupting effects. The development of genetically modified crops that are resistant to pesticides and that produce pesticides themselves, and the financial incentive of the chemical companies that produce the genetically modified organisms (GMOs) have resulted in increased pesticide applications. There is probably no place on earth that is not affected by pesticides. The solution is the adoption of integrated pest management practices that reduce the use of chemical pesticides and fertilizers in agriculture and the decoupling of the agrichemical and seed industry.