The greenhouse effect and the Arctic ice

The impact on the Arctic ice of global warming is important for many people and for the environment. Less ice means changed conditions for the Inuits, hard times for the polar bears and changed conditions for the fishing sector. There is at present some uncertainty about the thickness of the ice and what might be the cause of its oscillation. It was reported a few years ago that the thickness of the ice had almost been reduced by 50 per cent since the 1950s and some researchers suggested that within a few decades the ice would disappear during the summer. These measurements have turned out not to be representative for the whole Arctic region, and it now appears that a great deal of the measured thickness variation can be attributed to changes in the atmospheric circulation. The article discusses the Arctic Oscillation and the North Atlantic Oscillation in relation to the ice thickness, and climate models. Feedback mechanisms such as reduced albedo may have a big impact in the Arctic in a global greenhouse warming. Model simulations are at variance, and the scenarios for the future are uncertain