He's saying that when the IPCC came up with its sea level rise estimate, and the projections for what would happen in the north to the ice they couldn't agree on anything:

"they've come out with estimates for very small increases in sea level this century.  Well they only have quantified the thermal expansion of the ocean and the melting alpine glaciers and they have simply not dealt with this Greenland/Antarctic problem because it's difficult but it is by far the greatest threat as far as sea level is concerned"

So everyone is alarmed as it dawns on everyone that the ice is melting now.  Hansen's recent work concentrates on studying Earth's history to see what level of CO2 means no ice at the poles, he's decided its 450 ppm, so its out the window with the stated objective of Copenhagen, i.e. stabilizing the atmosphere at 450 ppm so we can avoid "dangerous" climate change. 450 ppm is a global catastrophe, according to Hansen.  Sea level rise beyond 200 feet, that's it for this age of life on Earth, wholesale global climate change, and international tension of the type that always led to war in the past.  And this is the target the big negotiations are aiming to bring us.

I heard an interview from Poznan on CBC The Current this morning with Bramley of Pembina.  The interviewer and Bramley took it as a given that limiting global warming to 2 degrees C, another way of stating the 450 ppm target level, could be taken to be "safe", and were busy criticizing all those in denial who didn't accept "the science" that says this.  Meanwhile Hansen's work was ignored. He's saying there's too much CO2 in the atmosphere right now.

Its a giant elephant in the room.  Its as if the Manhattan Project was under discussion in the media, Einstein had concluded that detonation of a single atomic bomb anywhere would mean the end of civilization, and everyone was pretending he hadn't concluded this as they discussed how to accelerate the project to save civilization.