Although average world temperatures have only risen 0.6°C in recent years, some arctic weather stations now show warming of 5°C. The thickness of some ice sheets has halved, and their area has reduced by 16%. Strange things are already happening in polar regions.
When ice forms from seawater in the Arctic it leaves the salt behind. The resulting cold, heavy, salty water drops to the ocean floor, creating 'pumps' that draw surface water, the Gulf Stream, and drive the Atlantic conveyor. The water in these pumps is now getting less saline, therefore lighter, because less water is freezing. It is also being joined by fresh salt-free water from melting icebergs. And it is getting warmer. If this process continues, a critical point will be reached and the pumps will stop.
