It is very fitting that this particular question is asked during the 40th anniversary of Earth Day this Thursday. Carson's work helped to initiate the environmental awareness movement that has been an integral part of America for the last forty years. Carson was ahead of her time in her assertion that there is a natural link between ecosystems and that there is a balance in which different organisms play roles in this web of interdependence. Human beings cannot presume any sort of separate condition or role outside of this context, but rather must seek to find solutions within it and ones that help to enhance the delicate balance of llfe. Carson's work is a landmark of the American environmental movement and a way of thought that is highlighted in the modern setting, but one that acquires greater meaning and significance this week.
The biggest thing that Carson did with regard to effecting change was to generate popular awareness for environmental issues. The most compelling reason for this as an argument for the text is the fact that everything she wrote about in the 1960s is still an issue today. Pesticides have come under more stringent regulations and both individuals and corporations have become more aware of the dangers of pesticide use, however, we as a society are still causing damage to the environment daily. The Kyoto protocol represents an international effort to become more environmentally aware, but not all countries have signed it. The issues are still present and the threats that Carson writes about have not gone away; however, because we are more aware of them on a worldwide scale, we stand a much better chance of doing something about them.
The book Silent Spring was written by Rachel Carson and was published in 1962. People usually give the book and its author credit for starting the environmental conservation movement that is so strong today.
The book was not about all environmental issues. Instead, it was about the bad effects of the pesticide DDT on birds. When people read the book, they put enough pressure on the government to do something that DDT was banned in the US some years later.
This is said to have started the environmental movement, which then spread to getting involved in other issues.
I would add to the answers above that because Carson's work eventually led to an almost complete global banof DDT's use, we are still effected by it today. While Silent Spring obviously brought attention to environmental issues, it also demonstrates how powerful environmental agencies can become. For example, because DDT is banned, the U.S. which sends a tremendous amount of aid to African each year to try to prevent malaria cannot encourage or provide funding for the use of DDT sprays which are far more effective at preventing malaria than the flimsy nets that we offer impoverished Africans instead. Since Carson's book was first published, several studies have shown that far more people die of malaria than from DDT-related issues (in fact, it has been difficult to prove that any die from DDT).
In the midst of today's plethora of environmental books and articles, Carson's Spring is still undeniably pivotal; unfortunately, it seems that many authors get away with presenting junk science which can actually end up harming more humans than their habitats.