Help with my research topic please!!!!!!!?

Ok, so this is the thing. We all have to do a research paper on anything we want and present it in front of the commitee and since we are given two full semesters to research the topic, the final result has to be perfect. By tomorrow I need to have my topic because I have to tell the teacher on Monday. All last week I was thinking about this, and I think that I would like to do something on Artic Ice Melting. This is a very broad topic and I'm having a difficult time narrowing it down. The paper could be either in a form of debate or exploration. I would prefer writing the exploration one but I don't know what would I talk about. It says in my notes: the exploration paper describes an issue or idea, notes any controversies, draws conclusions. Could my topic be an explanation paper and how could I narrow it down. Hope I didn't confuse you. Any idea would be great. Please, help!