The Hidden and External Costs of Pesticide Use

Abstract

A fair evaluation of the net benefits provided by pesticides is essential to feed the current debate on their benefits and adverse consequences. Pesticides provide many benefits by killing agricultural and human pests. However, they also entail several types of costs, including internal costs due to the purchase and application of pesticides, and various other costs due to the impact of treatments on human health and the environment. Here, we provide a comprehensive review of these costs and their evaluation. We define four categories of costs: regulatory costs, human health costs, environmental costs and defensive expenditures. Those costs are either internal to the market, but hidden to the users, or external to the market and most often paid by a third party. We analysed 61 papers published between 1980 and 2014, and 30 independent dataset. Regulatory costs reached very large values, e.g. US$4 billion yearly in the United States in the 2000s. However, if all regulations were respected, these costs would have jumped to US$22 billion in this country. Health costs studies generally did not take into account fatal cases due to chronic exposure such as fatal outcomes of cancers. Doing so would have increased estimates of health costs by up to tenfold, e.g. from US$1.5 billion to US$15 billion in the United States in 2005.

Most environmental impacts have never been quantified in the literature. Environmental costs were nevertheless estimated to up to US$8 billion in the United States in 1992. Although defensive expenditures have rarely been considered in the literature, they include at least the extra cost of the part of organic food consumption due to aversive behavior linked to pesticide use. This cost reached more than US$6.4 billion worldwide in 2012. Our review thus revealed that the economic costs of pesticide use have been seldom considered in the literature and have undoubtedly been strongly underestimated in the past. Despite this underestimation, we found that overall hidden and external costs ranged from US$5.4 million in Niger in 1996 to US$13.6 billion in the United States in 1992. We perform an updated and more complete retrospective evaluation of these costs in the United States and show that they probably reached the value of US$39.5 billion per year at the end of the 1980s-start of the 1990s. We also re-evaluate past benefit-cost ratio of pesticide use in various countries and reveal that the cost of pesticide use might have outreached its benefits, e.g. in the United States at the start of the 1990s. We finally advocate that the key impact to be evaluated is the cost of illnesses and deaths triggered and favored by chronic exposure to pesticides. The benefit-cost ratio of pesticide use may have easily fallen below 1 if this cost had been taken into account. The quantification of this key cost is therefore urgently required for a more accurate evaluation of pesticide use and for regulatory purposes.