I knew that climate change was occurring when I started working at AWI, but I was not aware of how rapidly the temperature is changing in the Arctic or to what extent it has changed the area of the sea-ice.
The thing is, that while temperatures are increasing all over the planet, the increase happens faster in the Arctic than anywhere else; studies show that the mean Arctic temperature in 2010 was 4 degrees C warmer than the average for 1968 to 2010. And 2010 was not a particularly warm year.
The most obvious impact of the rising temperature is that the extent of the summer sea-ice becomes gradually smaller with time. The September sea-ice extend, has almost been reduced by 40% since 1979. The picture below shows had the ice extend has changed since 1950, based on measurements and models.
The decrease in sea-ice does not just change the habitat for the ever popular Polar Bears, the increased freshwater content also changes the stratification of the water column, which can lead to changes in the ocean advection and mixing, in the nutrient supply, species composition etc. This can in turn further impact the climate in the Arctic but also globally. I guess I will get back to that in another post.
Other, and more obvious impacts of the reduced ice cover is, that it opens up for shipping across the Arctic Ocean, shortening the path from Europe to the Asia significantly and introducing hazards such as oil leaks to the Arctic environment. Also, drilling for oil may begin as the ice recedes.
Sea-ice has been continuously measured from space by satellites since 1979. Below I have added a film from NASA showing the record minimum of 2012, comparing it to the average distribution from 1968 to 1995.
The summer sea-ice extend has reached the lowest values in 2007 and 2012. 2016 does, unfortunately, appear to become another year with high Arctic temperatures and low sea-ice extend.