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The bulletin was launched in January 2011 in response to Network Ten's decision to move its weekend evening bulletin to 6pm - the network reintroduced a 5pm news two months later. The animated image below, based on NOAA data for the period December 7, 2011 - January 21, 2012, shows that specific areas can already experience anomalies of over 20 degrees Celsius for specific days. On January 6, 2011, the minimum temperature in Coral Harbour, located at the northwest corner of Hudson Bay in the province of Nunavut, Canada, was -3.7°C (25.3°F), i.e. 30°C (54°F) above average. The chart on the left, based on historic NASA land-surface air temperature anomaly data (see interactive map at the bottom of this page), shows that the average temperature anomaly rise in the Arctic (latitude 64 and higher) looks set to reach 10 degrees Celsius within decades. Note that above figures are for the average September extent, and thus somewhat higher than the annual minimum.


Above temperature anomalies have yet to incorporate the full impact of the various feedback effects. These anomalies are based on annual averages that are also averaged over a huge area. Annual minimums for sea ice area are displayed on the image below, produced by Larry Hamilton and based on data by Cryosphere Today. On September 8, 2011, sea ice extent as calculated by a University of Bremen research team led by Dr. Georg Heygster reached a record minimum of 4.24 million square kilometers, as illustrated by the image below, produced by Larry Hamilton. That is why if you compare extent and area in the same time period, extent is always bigger. The NSIDC image below shows that sea ice extent reached at August 5, 2012, reached a record low for the time of year. NSIDC recently featured an updated version (image below) showing the observed September sea ice extent for 1952 to 2011 (black line) against a backdrop of two models (in red and blue). Old versus new ice in Arctic: The maps show the median age of sea ice in March 1985 (left) and March 2011 (right).


Overall, the proportion of old ice has decreased. Note that, to calculate extent, the NSIDC includes areas that show at least 15% sea ice. National Snow and Ice Data Center (NSIDC). For updates, see the daily images produced by the NSIDC. The graph below was produced by Neven Acropolis of the Arctic Sea Ice Blog from Cryosphere Today data and featured at a post at Climate Progress entitled: Death Spiral Watch: Arctic Sea Ice Takes A Nosedive. Once the sea ice is gone, more light will instead get absorbed in the Arctic. The graph shows sea ice area levels for June 2012 that are well below levels of earlier years. Norwegian Polar Institute. As the sea ice cover decreases, less solar radiation is reflected away from the surface of the Earth in a feedback effect that causes more heat to be absorbed and consequently melting to occur faster still. The Danish Meteorological Institute also produces graphs showing that include areas with ice concentration higher than 15% to calculate ice extent. Ice extent has continued to decrease dramatically since 1995. Below are the figures for recent years as calculated by the U.S. As an example of such feedbacks, as the sea ice retreats, sunlight that was previously reflected back into space will get absorbed in the Arctic.


Extent would be a measure of the edges of the slice of cheese and all of the space inside it. Sea ice volume is typically calculated by combining measurements of sea ice extent and thickness. Much of the soot from firestorms in Siberia could settle on the ice in the Himalaya Tibetan plateau, melting the glaciers there and causing short-term flooding followed by rapid decrease of the flow of ten of Asia’s largest river systems that originate there, with more than a billion people’s livelihoods depending on the continued flow of this water. At the moment, the sea ice reflects light, helping formation of hydroxyl through tropospheric photolysis. How different would tropospheric oxidation be over an ice-free Arctic? Voulgarakis et al. The recent firestorms in Russia provide a gloomy preview of what could happen as temperatures keep rising in the Arctic. One study projects that this can cause late-summer hydroxyl concentrations to decrease by up to 60% in an ice-free Arctic. For individual days and locations, the anomaly can be even more striking. However, more methane causes hydroxyl depletion and methane levels in the atmosphere are already such that they have caused a 26% decrease in hydroxyl. Methane is predominantly broken down by hydroxyl.