Earthweek: A Diary of the Planet (Dec. 20, 2013)

Warming Wobble
The melting of ice caps and glaciers due to climate change is causing a shift in the Earth's axis, according to new research.  Wobbles in the planet's rotation are due to various influences, including the distribution of mass.  Observations conducted since 1899 have shown that the North Pole had been drifting south toward eastern parts of Canada at a rate of about 4 inches per year.  But that drift jogged abruptly eastward in 2005 and has moved about 4 feet in distance since then.  Jianli Chen of the University of Texas at Austin and colleagues collected data from NASA's GRACE satellite, which measures changes in Earth's gravity field over time in an attempt to find out why the shift occurred.  The measurements allowed them to calculate how melting of the Greenland and Arctic ice sheets and mountain glaciers, and the resulting rise in sea level, caused a redistribution of mass on the Earth's surface. Computer analysis determined that it matched perfectly what it would take to cause the observed shift in the North Pole's position.
Etna Eruption
Sicily's Mount Etna volcano produced its strongest eruption in recent months, spewing with such force that the local Catania airport was forced to close for two days because of ash plumes billowing into the sky.  Officials said that 150 flights were affected by the threat of volcanic debris.
Indian Ocean Cyclones
Tropical Cyclone Amara formed from an area of disturbed weather over the central Indian Ocean.  Cyclone Bruce developed to the south of Sumatra.  Both storms were predicted to be threats only to shipping lanes.
Arctic Ice Rebound
An unusually cool summer in the Arctic has led to almost 50 percent more sea ice covering the polar region this fall than the year before.  Measurements from Europe's CryoSat spacecraft reveal that about 2,160 cubic miles of sea ice covered the Arctic in late October.  That's up from the 1,440 cubic miles that CryoSat measured during the record low for the ice in 2012.  "Although the recovery of Arctic sea ice is certainly welcome news, it has to be considered against the backdrop of changes that have occurred over the last few decades," said Andy Dhepherd of University College London.  He told the BBC that there were about 4,800 cubic miles of Arctic sea ice each October during the early 1980s, decades before a rapid warming of the polar region brought unprecedented melting.
Ozone Healing Slow
Hopes that Earth's protective layer of stratospheric ozone was healing from decades of annual ozoneholes were dashed by the discovery that the upper atmosphere is still saturated with ozone-eating chemicals.  Speaking to a meeting of the American Geophysical Union, NASA atmospheric scientist Natalya Kramarova said that it should take until 2070 for Earth's shield against harmful ultraviolet radiation to fully recover from the widespread use of Freon and other damaging chlorofluorocarbons.  They have been phased out since the 1989Montreal Protocol agreement.  Shifts in weather around Antarctica can cause wide swings in the size of the ozone hole, making it difficult to tell if it is steadily becoming smaller.  It reached its largest size in 2006.  Kramarova estimates that it should become apparent by 2025 whether the ozone hole is truly recovering.
Earthquakes
Three people were injured in central China's Hubei province when a 5.0 magnitude temblor rocked the mountainous county of Badong. Approximately 96 homes were destroyed and about 2,500 others were severely damaged, according to a spokesman for the Miao Autonomous Prefecture.
*     Earth movements were also felt in metropolitan Tokyo, the northern Philippines, far southern New Zealand, California's San Joaquin Valley and south-central Kansas.
Reindeer Eyes
While Rudolph may have a red nose so bright it can guide an around-the-world flight on Christmas Eve, it seems all reindeer have eyes that change color to match the season.  New research reveals the Arctic species have eyes that reflect gold in summer and blue in winter, which helps them cope with the wide shifts of daylight between each season.  No other animal species has been found with such an ability.  Reindeer must find food and protect themselves from predators during almost-constant summertime sun in the Arctic as well as in the round-the-clock darkness of winter.  Their vision is helped by a change of pressure against a light-reflecting layer behind the retina when the eyes go from being dilated during the dark winters to being contracted during bright summers.  Writing in the journal Proceedings of the Royal Society B. researchers said the pressure shift causes a change in the color of reflected light in the eyes.  It also makes the reindeer's eyes between 100 and 1,000 times more sensitive to light in winter, increasing their chance of survival.