Environmental ethics, as a field of philosophical study, began in the 1970s and 1980s, in part as a result of the environmental movement and largely in Anglo-American work. Its roots trace to the monumental technological discoveries of the twentieth century, such as nuclear power and chemical pesticides; their overuse or misuse; and recognition of the environmental degradation these technologies have caused. Two paradigm examples of how the misuse of technology has caused massive environmental damage and consequently raised new ethical questions are DDT and nuclear power. From the point of view of the relative importance of human interests, the new field of environmental ethics can be divided roughly into anthropocentric, non-anthropocentric, and mixed approaches.