Sunday, September 16, 2007

Arctic sea ice at record low levels

Interesting article in today's paper about how ice cover over the Arctic is at its lowest level on record this year. Ice cover has shrunk to about 3 million square km, a million square kilometres less than the previous record lowest year in 2005. Data from the US's National Snow and Ice data Center give slightly different numbers.. showing ice coverage at 4.2 million sq km as of Sept 10th, still the lowest on record (previous record low was 5.3 million sq km in Sept 2005) Whatever the case, it's an amazing stat.. and certainly lends strong support to the global warming theory that has always warned of this consequence. Note however that these reliable ice cover records only go back to 1978 which is not a very long record to make any definite conclusions. One has to wonder what Arctic ice cover levels were like in the years before 1978, especially in the 1930s and 40s when we had some very extreme weather, and some very mild winters.

Nonetheless, you have to figure something is definitely changing up in the Arctic, and a continual reduction of the Arctic ice cover will have major impacts on our climate, sea levels, and economy (with the possible annual use of the Northwest passage) One of the impacts of a reduced Arctic ice cap is that winters would generally be starting later, and we have certainly seen this in southern MB with 8 of our past 10 Decembers warmer than average. So it does appear that we're already seeing some impacts of this exceptional loss of Arctic ice with delayed, shorter, and less severe winters.

It's interesting to note that Winnipeg had its warmest January on record in 2006, following the last record low Arctic ice cover in the fall of 2005. Will this mean we will have another record mild winter this year? Well, it's tough to say since there are other factors which can influence our winters such as a developing La Nina, and other global climatic oscillations. However, one has to certainly consider that there is a good possibility of another warm winter coming up for Southern MB given this year's amazing loss of Arctic sea ice.


  1. Interesting stuff. While the northern ice cap is at a record minimum the southern ice cap is at a record maximum. Does global warming only affect the Northern Hemisphere??

  2. Andrew..

    I hadn't heard that the southern ice cap was at a record maximum.. I thought it was shrinking as well, though not as quickly as the Arctic. Global warming would affect the whole planet, but its effects and impacts would be more noticeable sooner over the Arctic than the Antarctic.

    The Arctic ice cap is mainly over water, so it can more easily melt as the air and water get warmer. In fact, it's the open water that actually accelerates the ice-melting process and makes it harder for the ice sheet to grow back each winter. In effect, the Arctic ice cap is a slowly melting ice cube in the Arctic Ocean, and every year, that ice cube is getting smaller and smaller. The Antarctic ice cap on the other hand is mainly over land, and it's a much slower process to melt. So it's possible that it can get larger some years even though the Arctic ice cap is shrinking.

  3. Here is the link mentioning max ice cap in the south.

    Also some places in South America experienced well below average temps from May through September. Buenos Aires was around 2-3 degrees cooler than normal through this period.

    Not that I'm saying global warming isn't happening, I just found it very interesting that the southern Hemisphere is experiencing such cold temps compared to the Northern Hemisphere.