Is the earth really in peril due to greenhouse gases trapping heat or not? If so, is man really the cause?

Yes and Yes

And even if the answer to the second question was no, we still would have the responsibility to do something about it.

Moved to a more appropriate section

Yes there is climate change.. something that happens in cycles.

However I don't think that man created it.. just sped up the process and made it much worse through our pollutin' ways. *chuckles*