Protect the Environment Environmental problem is too big for individual countries and individual people to address. In other words, we have reached the stage where the only way to protect the environment is at an international level. I agree with that. First, the environment is an integrated system. The pollution air ejected from one place can be blown everywhere in the world. For example, there is a river which flows through many countries. If one contry pollute the river in the upstream, whatever the other contries do is in vain. Second, prisoner's dilemma. Prisoner's dilemma is a famous theory in economy. It very match the situation what we counter when we protect the environment. Every country is willing to take advantage of the other. They have the intent to do less in environment protection. If one country do less, the other will follow. It will become a vicious circle. So, the only way to protect the enviroment is at an international level.