For thousands of years the oceans have provided humankind with food and trade routes, and more recently with petroleum and minerals to fuel society. Since the 1960s, there has been a dramatic change in the general view of the oceans and the human impact on their sustaining ecosystems. In past times, little regard was given to disposal of wastes from ships. As greater understanding of the marine environment developed, it became clear that human behavior must change to ensure the health of that environment.