When did the issue about environment start?

I think you could probably trace it to the middle ages during and after the plaque. Up to that time people were pretty much only concerned with their own lives but as a result of the plaque they began to understand that garbage and sewage were a problem with their environment. It has evolved from there. As with all things, at some point people will go overboard. The other day I was reading about a group that believes we should all return to cave dwelling to protect the planet. Of course the people preaching that level of concern are probably not going to give up their computers, cell phones and so on.