Even though we face so many crisis, no one can deny that Earth are more suitable for human habitation. That is the result of the efforts of generations of people. If without that, we might also live in caves and eat the crude food just like wild animals. If that is true, we must haven‘t time and energy to think over the problems of the Earth because we have to look for food and avoid becoming the food of other animals. At that state, whether the Earth were harmed is not important for human because some certain crisises can annihilate the total population, such as some infectious disease or the a change of climates.
It is inevitable to produce some positive aspect functions when human are struggle to improve the survive abilities and from the experiences of history we also have make great effort to resolve this kinds of problems. For example, most of people hope to limit the scope of nuclear weapons and the protection of environment is accept by almost every one. Most of problems are controlled by ourselves and some of them have the hope to be resolved