Elixirs Of Death: Lessons From The Grave


Silent Spring revolutionised international attitude to pesticides. But 50 years on, have we lost touch with Rachel Carson’s legacy, and what could the future bring?

‘As crude a weapon as a cave mans club, a chemical barrage has been hurled against the fabric of life’ [1]

Rachel Carson. By Rex Gary Schmidt/U. S. Fish and Wildlife Service [Public domain], via Wikimedia Commons

Rachel Carson. By Rex Gary Schmidt/U. S. Fish and Wildlife Service [Public domain], via Wikimedia Commons

The green revolution is slowly stirring. ‘Organics’ are in the markets, recycling bins are spreading, and greenwash is in the air. But with our growing population, we still need to synthesize novel solutions to the environmental challenges we face. Food security is just one of these great challenges.

We have been trying to rid our crops of pests since 1947. The Agricultural Act, after World War II, put on pressure to increase farming outputs reducing degradation by crop pests. This led to the incorporation of organo-phosphate pesticides. In 1962, Rachel Carson’s Silent Spring was published, telling the story of the sinister impacts these chemicals were having on human health and the environment. The agrochemical companies called her an unmarried communist spinster: Silent Spring was nothing but propaganda. Yet her story was so powerful, legislative changes were eventually enforced to draw these ‘elixirs of death’ off the market [1].

Whilst Carson’s legacy resonates, the future for sustainable agriculture remains uncertain. The Precautionary Principle states the evidence be consulted before policies are implemented; but despite an abundance of nature writing, science, and public campaigns, barriers to success remain hard-broken.

Missing the evidence

‘It is ironic to think that man might determine his own future by something so seemingly trivial as the choice of an insect spray’ [1]

Whilst pests became resistant to chemicals, controversial alternatives to reduce crop degradation comprised genetically modified organisms (GM), biological controls, or the synthesis of new chemicals. GM offers the ‘natural’ incorporation of bacterium to harm the consuming pest (transgenic or biopesticide). Whilst studies endeavoured to find negative effects of GM on wild animals [2], sinister reports of ‘a suicide epidemic’ in India began an investigation into the socio-economic impacts of annual GM seed contracts by industrial distributors [3]. For many, consumption of the artificially enhanced is an unsavoury concept beside the science.

Biological control, another ‘natural’ method, involves incorporating pest predators or parasites into the agroecosystem. Whilst some are a success, others become paradoxically established as pests themselves. The Japanese Harlequin ladybirdHarmonia axyridis, enjoyed an unexpected, intractable spatial expansion across Europe, following an introduction in France (after misinterpreting some field and lab assays) [4]. Consuming UK native ladybirds and entering British households, this Asiatic invasive is a principle example of the failure to recognize evidence.

Figure 2 – Relationship between mean passerine bird population trends versus imidacloprid concentrations in the Dutch surface water between 2003 and 2009. Figure adapted [4]

Figure 2 – Relationship between mean passerine bird population trends versus imidacloprid concentrations in the Dutch surface water between 2003 and 2009. Figure adapted [4]

Pollination is big money. Bees help to fertilize almost ⅓ of the worlds crops; the same crops we cover in pesticides. In Spring 2013,the EU ruled in favour against the use of neonicotinoids, a set of neurotoxic pesticides thought to be harmful to bees and other wildlife. Insecticides are absorbed systemically into the plant, leading to the ingestion of toxic nectar. Following a petition that incurred over 3 million signatures, the European Commission banned 3 major neonicotinoids for a two-year period. Some are adamant the evidence is not sufficient. Others argue we’ll only turn to organo-phosphates or export-crops. Nonetheless, neonicotinoids have been documented to negatively impact several aspects of bee behaviour, whilst a recent article in Nature documented the decline of wild birds in response to neonicotinoid imidacloprid [5] (Figure 2). The paper was not regarded highly, heavily relying on correlations. Further research for evidence is currently underway.

A future for agriculture

‘Only within the moment of time represented by the present century has one species – man – acquired significant power to alter the nature of the world’ [1]

It seems there are downsides to every solution. But innovative research is offering something different. A project in Japan aims to augment agricultural output by augmenting biodiversity, creating a cyclic self-sustaining system; they call it ‘Synecoculture’. Incorporating theoretical ecology into a layman’s garden, they hope to diversify what we consume; just 75% human food originates in just 12 plant and 3 animal species. Enhancing knowledge of crop varieties, seasonality, and biodiversity may contribute to global acceptance of Synecoculture.

In 2008, the Food and Agriculture Organisation of the United Nations (FAO) proposed that ‘entomophagy’ (eating insects) offers a novel solution to food security. Locust meat harbours almost equal protein content to beef. It can be harvested seasonally, and at substantial quantities, and is readily practiced in many developing nations. These solutions require as much public engagement as they do ecological science. It seems a cultural transformation is the answer.

The green revolution needs some coaxing. Should we write our wrongs to inspire others into good sense? Where evidence fails to satisfy policy, clear communication like Carson’s offers accessible translations to those that matter. We certainly need legislation regulating distribution and non-bias testing to minimise social and environmental disruption. Some research indicates the answer lies in food waste, worth just $750 billion USD annually. Others advocate we should prepare for ‘Climate Smart Agriculture’ to contend with a warming planet; perhaps novel solutions, like synecoculture or entomophagy, hold the answers. But one thing’s for certain: writing a future for food security is going to take some persuading.

Literature

[1] Carson R (1962) Silent Spring. Houghton Mifflin,USA

[2] O’Callaghan M, Glare TR, Burgess EPJ, Malone LA (2005) Effects of plants genetically modified for insect resistance on nontarget organisms. Annual Review of Entomology 50:271-292

[3] Gruére GP, Mehta-Bhatt P, Sengupta D (2008) Bt cotton and farmers suicides in India. International Food Policy Research Institute Report. Washington, USA.

[4] Brown PMJ, Thomas CE, Lombaert E, Jeffries DL, Estoup A, Handley LJL (2011b) The global spread of Harmonia axyridis. (Coleoptera: Coccinellidae): distribution, dispersal and routes of invasion. Biocontrol 56:623-641

[5] Hallmann CA, Foppen RPB, Turnhout CAM, de Kroon H, Jongejans H (2014) Declines in insectivorous birds are associated with high neonicotinoid concentrations. Nature DOI:10.1038/nature13531

This blog originated on the University College London (UCL) MRes Biodiversity Evolution Conservation website, and was written as part of our class assignments.

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