More than six decades after Rachel Carson’s Silent Spring alerted the world to the dangers of pesticides, a new analysis reveals that the overall toxicity of these chemicals is increasing globally. The study, led by Ralf Schulz at RPTU University Kaiserslautern-Landau, points to a disturbing trend: despite regulations, the amount and potency of pesticides used worldwide are growing.
Measuring the Toxic Burden
The researchers assessed the “applied toxicity” of 625 pesticides across 201 countries from 2013 to 2019. This metric combines the quantity of pesticides used with their toxicity to eight key groups of organisms, including pollinators, fish, and terrestrial vertebrates. The findings are stark: total applied toxicity rose in six out of eight groups during this period. For example, toxicity for pollinators increased by 13%, for fish by 27%, and for insects by 43%.
This rise isn’t necessarily a direct translation to immediate harm, but it functions as a vital indicator. It shows that the pesticides being deployed are becoming more dangerous to crucial species.
Why Toxicity is Increasing
Two primary factors drive this trend: increased pesticide usage and the replacement of older chemicals with more potent ones. This is largely due to pest resistance; as insects and weeds evolve to withstand existing pesticides, farmers turn to stronger, more toxic alternatives.
Pyrethroids, commonly used but highly damaging to fish and aquatic invertebrates, are a key concern. Similarly, neonicotinoids pose a significant threat to pollinators. Even widely debated herbicides like glyphosate (Roundup) contribute to the overall toxic load, despite having relatively low individual toxicity, due to the sheer volume used.
The Limits of Regulation and Risk Assessment
The study highlights a systemic problem: risk assessments consistently underestimate real-world pesticide exposure. Data shows that pesticide concentrations in environments like rivers often exceed the levels regulators deem possible.
Furthermore, attempts to reduce pesticide use can backfire. A glyphosate ban, for instance, could lead to the adoption of even more toxic alternatives. Similarly, reducing farm productivity could necessitate expanding farmland, resulting in greater biodiversity loss.
The UN Target and the Path Forward
In 2022, countries at a UN biodiversity summit agreed to cut the “overall risk” from pesticides by half by 2030. However, the term “risk” remains undefined, making meaningful measurement difficult. Experts suggest that applied toxicity could serve as a quantifiable metric.
While no measurement system is perfect, the trend is clear. The world is currently moving away from this target, which poses a severe threat to ecosystems and human health. The study emphasizes that a small number of highly toxic pesticides drive most of the overall risk, suggesting that targeted action could yield significant benefits.
Ultimately, transforming agriculture requires a broader societal shift. Consumers must be willing to accept dietary changes, reduce food waste, and pay fair prices that reflect the true environmental costs of production. Only through systemic change can we begin to reverse this escalating toxic burden.
