A recent slowdown
July 18, 2017

Arctic extent nearly matched 2012 values through the first week of July, but the rate of decline slowed during the second week. Weather patterns were unremarkable during the first half of July.


Overview of conditions

As of July 17, Arctic sea ice extent stood at 7.88 million square kilometers (3.04 million square miles). This is 1.69 million square kilometers (653,000 square miles) below the 1981 to 2010 average, and 714,000 square kilometers (276,000 million square miles) below the interdecile range. Extent was lower than average over most of the Arctic, except for the East Greenland Sea (Figure 1). Hudson Bay was nearly ice free by mid July, much earlier than is typical, but in line with what has been observed in recent years.

Parkinson used microwave data collected by NASA and Department of Defense satellites for her study, which was published last December in the Journal of Climate. She added Arctic and Antarctic sea ice extents month by month from November 1978 to December 2013 to determine the global ice extent for each month. Her analysis shows that over the 35-year period, the trend in ice extents was downward in all months of the year, even those corresponding to the Arctic and Antarctic sea ice maximum extents.

three graphed trend lines
Comparing Arctic sea ice loss to Antarctic sea ice gain shows that the planet has-been shedding sea ice at an average annual rate of 13,500 square miles since 1979, the equivalent of losing an area of sea ice larger than the state of Maryland every year.
Credits: NASA's Earth Observatory/Joshua Stevens and Jesse Allen
Furthermore, the global ice decrease has accelerated: in the first half of the record (1979-96), the sea ice loss was about 8,300 square miles (21,500 square kilometers) per year. This rate more than doubled for the second half of the period (1996 to 2013), when there was an average loss of 19,500 square miles (50,500 square kilometers) per year – an average yearly loss larger than the states of Vermont and New Hampshire combined.

“This doesn’t mean the sea ice loss will continue to accelerate,” Parkinson said. “After all, there are limits. For instance, once all the Arctic ice is gone in the summer, the Arctic summertime ice loss can’t accelerate any further.”

Sea ice has diminished in almost all regions of the Arctic, whereas the sea ice increases in the Antarctic are less widespread geographically. Although the sea ice cover expanded in most of the Southern Ocean between 1979 and 2013, it decreased substantially in the Bellingshausen and Amundsen seas. These two seas are close to the Antarctic Peninsula, a region that has warmed significantly over the last decades.

In her study, Parkinson also shows that the annual cycle of global ice extents is more similar to the annual cycle of the Antarctic ice than the Arctic ice. The global minimum ice extent occurs in February of each year, as does the Antarctic minimum extent, and the global maximum sea ice extent occurs in either October or November, one or two months after the Antarctic maximum. This contrasts with the Arctic minimum occurring in September and the Arctic maximum occurring in March. Averaged over the 35 years of the satellite record, the planet’s monthly ice extents range from a minimum of 7.03 million square miles (18.2 million square kilometers) in February to a maximum of 10.27 million square miles (26.6 million square kilometers) in November.

“One of the reasons people care about sea ice decreases is that sea ice is highly reflective whereas the liquid ocean is very absorptive,” Parkinson said. “So when the area of sea ice coverage is reduced, there is a smaller sea ice area reflecting the sun’s radiation back to space. This means more retention of the sun’s radiation within the Earth system and further heating.”

Jovial Monk wrote on Jul 29^th, 2017 at 2:32pm:





By Barbara Hollingsworth | September 13, 2013 | 12:05 PM EDT

(CNSNews.com) –  A 2007 prediction that summer in the North Pole could be “ice-free by 2013” that was cited by former Vice President Al Gore in his Nobel Peace Prize acceptance speech has proven to be off… by 920,000 square miles.

In his Dec. 10, 2007 “Earth has a fever” speech, Gore referred to a prediction by U.S. climate scientist Wieslaw Maslowski that the Arctic’s summer ice could “completely disappear” by 2013 due to global warming caused by carbon emissions.



http://www.cnsnews.com/news/article/barbara-hollingsworth/wrong-al-gore-predicte...

Al Gore is not a scientist. Nor is the liar Dubyne.