“Arctic Ice Volume Lowest Ever as Globe Warms: UN,” is how Reuters reported it today. Sorry I missed that in my earlier post on the 2008 report from the World Meteorological Organization, but it was buried deep in the press release (see below).
Note that the WMO is making a stronger statement than the National Snow and Ice Data Center did in October.
The NSIDC figure (click to enlarge) compares ice age in September 2007 (left) and September 2008 (right). It shows the sharp increase in thin first-year ice (red) and the decline in thick multi-year ice — both “second-year ice” (orange) and “third-year and older ice” (yellow). “White indicates areas of ice below ~50 percent, for which ice age cannot be determined.”
The WMO release says of the Arctic:
Arctic sea ice extent during the 2008 melt season dropped to its second-lowest level since satellite measurements began in 1979, reaching the lowest point in its annual cycle of melt and growth on 14 September 2008. Average sea ice extent over the month of September, a standard measure in the scientific study of Arctic sea ice, was 4.67 million km2. The record monthly low, set in 2007, was 4.3 million km2.
Because ice was thinner in 2008, overall ice volume was less than that in any other year.
A remarkable occurrence in 2008 was the dramatic disappearance of nearly one-quarter of the massive ancient ice shelves on Ellesmere Island. Ice 70 metres thick, which a century ago covered 9 000 km2, has been chiseled down to just 1 000 km2 today, underscoring the rapidity of changes taking place in the Arctic. The season strongly reinforces the 30-year downward trend in Arctic sea ice extent.