Extreme Events

If we take a look on the news, we will see examples of extreme events. All of us have seen those extremely low temperatures and huge snowfall storms along United States during the last month or, the bushfires that were burning for weeks in New South Wales, Australia, in October before the beginning of the warm season. 

Three sisters, Blue Mountains, New South Wales, picture taken in April, 2011. 

In order to explain Extreme events, I will use some figures from NOAA climate.gov.

Antarctica sea ice reached the highest extent ever recorded by satellites on September 26, 2012. The monthly average was a high record, as well, exceeding the previous record in 2006. Scientists believe that this can be explained by the stronger circumpolar winds in the Southern Hemisphere. These stronger winds push ice away from the coast, expanding the sea ice extend around many parts of the continent. 

Percent difference from average (1979-2000) sea ice concentration around Antarctica during January 2012 (summer minimum) and September 2012 (winter maximum).Dan Pisut, based on data from the National Snow and Ice Data Center.Source: Climate.gov - http://www.climate.gov/sites/default/files/bigJan_Sept_2013-IceAnom.jpg

If we take a look on Arctic sea, we have a completely different situation. On September 16, 2012, Arctic sea ice reached the lowest extent ever recorded.  

Ice concentration on September 16 compared to previous record low (yellow line) and the mid-September median extent (black line). Dan Pisut, NOAA EVL, based on datafrom the National Snow and Ice Data Center. Source: Climate.gov - http://www.climate.gov/sites/default/files/bigSeaIce-Sept162012.jpg

How can we explain those differences between the Poles?

The Antarctica is a continent covered by continental ice which has the Antarctic circumpolar current keeping the warm ocean waters away from the white continent. On the other hand, the Arctic Ocean is surrounded by continents and has a more complex circulation. We have water exchange in two main locations, the Bering Strait with the Bering Sea, Pacific Ocean; and between Greenland and Norway with the Atlantic Ocean. The wind patterns circulation is different for the Poles, as well.

As the Arctic warms, less reflection due to the sea ice melting, and having a temperature rise. 

If you want to learn more about Extreme Events on 2012, have a look on the following link: http://www.climate.gov/sites/default/files/bigextremes-201213_BAMSoriginal.jpg

Useful links:

NOAA - http://www.climate.gov/news-features/featured-images/state-climate-extreme-events

WHOI: Arctic Ocean Circulation - https://www.whoi.edu/main/topic/arctic-ocean-circulation

The Extreme Events in the Arctic and the Antarctica discussion belong to the Future Learn course on Climate Change by the University of Exeter.