THE history of life on earth is, at its core, a history of interaction between living organisms and their environment. For most of that history, life adapted to surrounding conditions rather than reshaping them. Humans, like all other species, were long shaped by ecological forces far greater than their own. Yet within the last century, one species has acquired unprecedented technological power to alter the natural world. In doing so, humanity has increasingly positioned itself not as part of nature, but as its master, with consequences that are now impossible to ignore.
Long before human civilisation emerged, insects thrived on earth as one of the most diverse and adaptable groups of living organisms. Of the more than half a million known insect species, only a small fraction has historically conflicted with human interests, mainly as competitors for food or as carriers of disease. Under traditional agricultural systems, these conflicts were limited. Insect populations were regulated through ecological diversity, natural predators and crop variation. Problems intensified only with the commercialisation and industrialisation of agriculture, particularly through the expansion of monoculture farming.
By dedicating vast areas to single crops, humans dismantled nature’s own system of checks and balances. Biodiversity, which acts as a natural safeguard against pest outbreaks, was replaced by simplified landscapes that encouraged explosive population growth of specific pests. The post-war culture of science, driven by confidence in human dominion over nature, became the philosophical root of this imbalance.
Human efforts to control pests did not begin with modern chemicals. Early agricultural societies relied on natural substances with limited persistence. Sulphur, used by the Sumerians as early as 2500 BCE, is the earliest recorded chemical pesticide. Ash, lime, plant extracts such as neem in South Asia and chrysanthemum in China, nicotine-based insecticides, and natural oils and resins were commonly employed. These methods were crude but comparatively benign, breaking down quickly without long-term environmental accumulation.
The nineteenth century marked a decisive shift. Inorganic chemical pesticides began to dominate agricultural practice, particularly arsenic-based compounds such as Paris Green and London Purple. Copper sulphate mixed with lime, known as the Bordeaux mixture, was widely used to combat fungal diseases in vineyards. Mercury compounds were introduced as seed treatments. While effective in suppressing pests, these substances were acutely toxic to humans and livestock, deployed at a time when little was understood about environmental persistence or cumulative exposure.
The early twentieth century brought further escalation. Industrial expansion enabled the mass production of arsenical pesticides, while hydrocyanic acid fumigation became common for stored products. Research conducted during the two World Wars, particularly in chemical warfare, accelerated pesticide innovation. This momentum culminated in the synthetic pesticide revolution of the 1940s to 1960s, when organochlorines such as DDT or dichlorodiphenyltrichloroethane, aldrin and dieldrin, alongside organophosphates and carbamates, were adopted enthusiastically in post-war agriculture. These chemicals prioritised short-term pest control while carrying high risks to human health and ecosystems.
Rachel Carson’s Silent Spring, published in 1962, exposed the ecological devastation caused by the indiscriminate use of synthetic pesticides. Her work brought concepts such as bioaccumulation, biomagnification and pesticide resistance into public consciousness and sparked a global environmental movement. This shift led to restrictions on persistent organochlorines and the establishment of environmental protection bodies, including the United Nations Environment Programme.
Despite these lessons, chemical dependency in agriculture has deepened. From the 1980s onwards, newer chemical classes such as synthetic pyrethroids, neonicotinoids, phenylpyrazoles and broad-spectrum herbicides were introduced. Though marketed as more selective and applied at lower doses, many remain ecotoxic and controversial. Integrated Pest Management, incorporating biological controls, has been promoted in confirming documents, but its practical adoption remains limited. Meanwhile, pollinator decline, human health risks and accelerating pest resistance continue to demand ever-greater chemical inputs.
The scale of chemicalisation is stark. Global pesticide use rose from 2.2 million tonnes in 2000 to 3.73 million tonnes in 2023, an increase of over 70 per cent. Application rates have similarly climbed. Bangladesh mirrors this trajectory, with pesticide application rates quadrupling over two decades. The use of acaricides, fungicides, herbicides and rodenticides has risen sharply, according to industry data. Fertiliser consumption has followed a comparable path, both globally and domestically, reinforcing the chemical intensity of modern agriculture.
The environmental costs are profound. Non-target species, including pollinators, birds and aquatic life, are routinely harmed. Predator–prey relationships collapse, biodiversity declines and toxic substances persist through food chains via bioaccumulation. Soil and water systems suffer long-term contamination, damaging fisheries, wetlands and drinking water sources. For humans, the consequences range from acute poisoning among agricultural workers to increased risks of cancer, neurological disorders, endocrine disruption and birth defects.
These outcomes are inseparable from the legacy of the industrial revolution, which transformed agriculture through mechanisation, monoculture and an ideology of control over nature. The Green Revolution further intensified this trajectory, pairing high-yield crop varieties with heavy chemical inputs to meet the demands of a growing global population. The promise of ‘better living through chemistry’ has instead delivered a cycle of dependency, where pest resurgence and resistance drive the continual escalation of toxicity.
Modern pesticides are often misnamed. Many are not selective insecticides but biocides, capable of killing all forms of life in their path. The resulting chemical war against nature is unwinnable. Persistent organic pollutants now contaminate ecosystems and human bodies alike, with the capacity to disrupt genetic integrity across generations. This chemical corruption of the environment represents an act of collective hubris, fuelled by ignorance, commercial interests and short-term thinking.
If self-preservation is to mean anything, humanity must regulate its appetite for chemical domination. The choice is no longer between productivity and restraint, but between ecological collapse and a reimagined relationship with the natural systems that sustain life.
Dr Md Sohrab Ali is a former additional director general of the environment departmet.
