Is human activity bringing about alarming global warming scenarios and related catastrophes?

Given the extreme weather conditions manifesting all over the world (tsunamis, hurricanes, extreme hot and cold weather, glacier melting, etc.) the debate about climate change is again front and center. Terms like El Niňo and La Niňa further complicates the debate. Question: Is human activity bringing about alarming global warming scenarios and related catastrophes? Or is such thinking a myth brought about by flawed or incomplete science? Finding the answers to these questions has turned global warming into a highly politicized and contentious issue. What are the key issue issues in the global warming debate? Please take a position (pro or con) on global warming and support your position with references to course readings and outside sources.