Rachel Carson: The green revolutionary

The book that changed the world is a cliché often used but rarely true, yet 50 years ago this week a book appeared which profoundly altered the way we view the Earth and our place on it: Rachel Carson's Silent Spring.

This impassioned and angry account of how America's wildlife was being devastated by a new generation of chemical pesticides began the modern environment movement: it awoke the general consciousness that we, as humans, are part of the natural world, not separate from it, yet we can destroy it by our actions.

A middle-aged marine biologist, Carson was not the first to perceive this, to see how intimately we are bound up with the fate of our planet; but her beautifully-written book, and the violent controversy it generated, brought this perception for the first time to millions, in the US, in Britain and around the world.

Down the centuries many people had expressed their love for nature, but Silent Spring and the furore it created gave birth to something more: the widespread, specific awareness that the planet was threatened and needed defending; and the past half-century of environmentalism, the age of Green, the age of Save The Whale and Stop Global Warming, has followed as a natural consequence.

When it began serialisation in The New Yorker on 16 June 1962 (it was published in full the following September) Silent Spring revealed to a horrified America – or at least, to those who did not know already – that its wildlife was being wiped out on a staggering scale by use of the new generation of synthetic pesticides, compounds made in the laboratory rather than from naturally occurring substances, which had followed on from the forerunner of them all, the chlorinated hydrocarbon DDT.

In particular, the songbirds of America's countryside and small towns were everywhere falling silent. They had been killed by colossal pesticide spraying programmes, usually from the air, sanctioned in the 1950s by the US Department of Agriculture, individual states and local authorities, and aimed at insect pest threats which turned out to be largely illusory.

There was no need for them; their real driver was the American chemical industry which had managed to convince US agriculture that its bright new range of deadly super-poisons, organochlorines such as aldrin and dieldrin, organophosphates such as parathion and malathion, were just the wonder drugs that farming needed – in huge doses.

Even now, it is hard to read Rachel Carson's account of these mass sprayings without incredulity, like the 131,000 acres in Sheldon, Illinois, sprayed with dieldrin to get rid of the Japanese beetle. "It was a rare farm in the Sheldon area that was blessed by the presence of a cat after the war on beetles was begun," she wrote.

Tens of millions of acres were covered in poison in campaigns against the spruce budworm, the gypsy moth and the fire ant, none of which succeeded in eradicating their targets, but all of which exterminated countless other wild creatures – the American robins on suburban lawns, the trout in forest streams – to the bewildered dismay of the local people watching it happen around them.

Carson's achievement was to bring the situation to national notice in a remarkable synthesis of dramatic reportage and deep scientific knowledge, explaining exactly what the new pesticides were, how their catastrophic side effects were occurring, and how senseless were the mass spraying campaigns (although she recognised that agricultural pesticides were necessary and did not advocate banning them all). To a reader today, her account is compelling and entirely convincing.

Yet it produced an explosion. The US chemical industry, and parts of the US scientific establishment, lashed out in frenzy against this presumptuous upstart holding them to account, with a long and bitter campaign of criticism and personal denigration; and it seemed as if what aroused their ire more than anything was the fact that their opponent was a woman – "An hysterical woman".

A professional biologist from Pennsylvania who had worked for the US Fish and Wildlife Service, she was 55 when Silent Spring appeared. Unmarried and childless after a life spent looking after her mother and her young nephew, she had found emotional solace in a deep friendship with a neighbour at her Maine holiday home, Dorothy Freeman, about which there has inevitably been speculation; certainly, they were very close. Yet Carson was more than a scientist, she was also an acclaimed author, having written a trilogy of highly-praised books on the marine environment, one of which,The Sea Around Us of 1951, had been a best-seller.

Thus when Silent Spring appeared, she already had a substantial audience, and the furore stirred up by the US chemical industry only served to boost it a thousandfold; by the end of 1962, three months after full publication, the book had sold half a million copies, and public opinion was solidly behind her. (It did nothing to hinder her cause that President John F Kennedy took her side and referred Silent Spring to his Science Advisory Committee, which the following year vindicated her stance.)

So the madness of the mass poison sprayings came to an end, and the robins and their song returned to America's spring; DDT was banned for agriculture in 1972 (although it remained in use for malaria prevention), and bans on dieldrin, aldrin and other substances followed.

Rachel Carson did not live to see it: she died of cancer in 1964. But her achievement was much more than to end a crazy and murderous assault upon nature, enormous though it was.

What she introduced to a mass audience for the first time, in explaining how the catastrophe was happening, was the idea of ecology, of the interconnectedness of all living things, of the connectedness between species and their habitats.

The pesticide falls on the leaf, and the leaf falls to the ground where it is consumed by worms, who also consume the pesticide; and robins consume the worms and consume the pesticide too, and so they die.

In showing how everything in the natural world was linked, she showed how humans were part of it too, and how human interference could wreck it, could wreck the balance of nature built up over billions of years.

That is a commonplace insight now, but in 1962 it was a new one. It was truly radical, because it implied – for the first time ever – that scientific advance and economic growth, closely linked as they were in America, might not be endlessly a good thing. There was the Earth itself to consider. And that perception has been at the heart of the movement that Silent Spring inspired, which is 50 years old on Saturday.

Spreading death: the new pesticides

Insecticides made from natural products, such as pyrethrum from chrysanthemum flowers and naturally occurring arsenic, had been known and used for centuries, before the more powerful effects of synthetic lab-produced pesticides became apparent during the Second World War.

The first was dichlorodiphenyltrichloroethane – DDT – synthesised in the 19th century but whose insect-killing properties were only discovered in 1939. DDT was used with success in disease prevention during the war and was followed during the 1940s and 1950s by a family of similar organic chemicals.

However, the new organochlorines and organophosphates were not just more deadly, they built up in body fat and the accumulated dose could be passed on. "One of the most sinister features of DDT and related chemicals is the way they are passed on from one organism to another through all the links of the food chains," Rachel Carson wrote.

The deadliest of these chemicals have now largely been banned, but controversy over pesticide use and its effect on wildlife has not gone away. It now focuses on the neonicotinoids, one of which, thiamethoxam, was banned by the French government last week after research showed it affected the homing ability of bees.