Big Hollywood your comment of "with a thickness of 3 km in the middle" where is your proof on that!! There was a team that went from Canada to the North Pole measuring ice thickness and they found mostly first year ice and the average was around 3m thick. There is more to global warming then just the amount of ice on the North Pole. There is Permafrost melting, Sea level rise, Drought "look that up in Google news", coral bleaching, dead zones in the gulf, Magnetic field of the earth moving"Why maybe because of ice mass displacement". CO2 and Methane is increasing and the only thing we don’t know for sure is the effect it will have on the planet. We can only go by the ice core samples taken and examined that show temperature has increased when the amount of CO2 increased. Every one will tell it is getting hotter. Some say it is a cycle and some say it will keeping going up untill bad things start happening.