For most of the twentieth century, the chemical industry sold the world a simple bargain: synthetic compounds would liberate humanity from scarcity, disease, and drudgery. Plastics replaced metal, pesticides replaced crop rotation, and refrigerants replaced ice. These were marketed as triumphs of human ingenuity, but they were also lucrative patents, vertically integrated conglomerates, and the physical expression of a Promethean confidence that nature could be improved upon. Some of the results were spectacular—the Green Revolution, the eradication of malaria in entire regions—but most of the tens of thousands of chemicals that now circulate through the biosphere have attracted little scrutiny. These are the quiet, though not inconsequential, substances that today contaminate the blood of nearly every living human. Chances are, what your supermarket calls "fresh" is laced with residues, and that clear stream that runs past it once carried a very different chemistry.
Introducing a novel compound into the environment is always a partial act. Even when explicit goals—yield, profit, convenience—were met, other consequences were significant and often insidious. Across the world, industrial chemistry displaced millions of smallholders, undermined traditional foodways, and concentrated power in a handful of corporations. In the global South, pesticides were often an instrument of dependency, used to indebt farmers and subsidize export agriculture. And as these compounds accumulated in soil, water, and tissue, they disrupted endocrine systems, thinned bird eggshells, and bred resistance in the very pests they were meant to kill. Declining insect populations are the most visible effect, but synthetic chemicals also threaten a host of other organisms—from amphibians and lichens to soil microbes—with collapse. Every major chemical, then, is also a sacrifice zone, a place where lives, livelihoods, and ecosystems are altered so that new sorts of landscapes can support yield-intensive agriculture and the cities that consume it. Such sacrifices have been justified as offerings at the temples of progress—justified by and for whom, though? Over the course of the twentieth century, rarely were the costs and benefits weighed thoughtfully and decided democratically. As the biologist Rachel Carson warned in 1962, "For the first time in the history of the world, every human being is now subjected to contact with dangerous chemicals, from the moment of conception until death." Sixty years later, Carson's words ring ever truer. A litany of compounds approved in the mid-twentieth century are only now being evaluated for their long-term effects, with worrying prospects for their safety. Regulations, weakened and fragmented by the very industries they are meant to police, have failed to keep pace. If ever there were a time to rethink the mania for synthetic chemistry, it would be now.
There is some evidence that a combination of public opposition, greener alternatives, and a lack of viable markets has slowed the introduction of major new compounds. But a wave of recent and ongoing production, from India and China to Brazil and Canada, continues to tilt the global balance firmly in favor of synthetic chemistry.