I think 2012 will be much like any other year. I feel climate change is on exponential slope. 2012 will definitely take some records in the climate department but so will 2013. I don't think 2012 will be anything super special.
The world has gone the climate changes time and time again without any human influence. The difference is we are here to witness record and measure it.
I do feel however that 2012 will be a landmark year politically.