Example 1: I think global warming is a truth as we can see many climatic disasters in daily newspaper.
Example 2: The realty of current global warming is a controversial issue (argument). Scientists studying Antarctic ice layers are saying it`s a cyclic phenomenon and nothing to worry about. While we have also report of abrupt changes of temperature and sea level (example). Saying that, I think we are living in the era of sudden global warming (opinion).
It can be concluded that... (we are living in the era of global warming)