For the past century, the world's great powers have pursued better living conditions, fought against each other and worked frantically to develop technologies useful for fighting wars, all in total disregard of the environment.
If this continues, the Earth's environment will become so contaminated that sooner or later the death knell will sound for the human race.
Scientists estimate that the Earth came into being 4.5 billion years ago, and that humans first appeared 5 million to 6 million years ago. Since its appearance on Earth, the human race has done nothing but damage other forms of life in pursuit of its own happiness.