Hey Thorny,
Last year I was required to write an essay in response to a very similar question to the one you have yourself there. As I am sure you're already aware, there's loads of information out there in cyberspace, and a lot of it says the same thing.
My advice to you would be to go in search of views that oppose what is generally accepted. For example, there are those who still believe global warming doesn't even exist and insist there is no proof that it is responsible for any of the changes we are experiencing right across the globe. This will show you have considered 'what everyone else thinks' before deciding what you think, yourself.
I doubt that is much help, but I don't think you will need any more than that. Just make sure you have enough information and you organize it effectively.
Good Luck!
