Weird weather -- why? Jan 25, 2011 17:27:36 GMT
Post by bixaorellana on Jan 25, 2011 17:27:36 GMT
For two winters running, an Arctic chill has descended on Europe ... Last year in the United States, historic blizzards afflicted the mid-Atlantic region. This winter the Deep South has endured unusual snowstorms and severe cold...
Yet while people in Atlanta learn to shovel snow, the weather 2,000 miles to the north has been freakishly warm the past two winters. Throughout northeastern Canada and Greenland, temperatures in December ran as much as 15 to 20 degrees Fahrenheit above normal. Bays and lakes have been slow to freeze; ice fishing, hunting and trade routes have been disrupted.
2010 [has] gone down as one of the strangest years in the annals of climatology, thanks in part to a weather condition known as El Niño, which dumped heat from the Pacific Ocean into the atmosphere early in the year. Later, the ocean surface cooled, a condition known as La Niña, contributing to heavy rainfall in many places.
Despite cooling from La Niña, newly compiled figures show that 2010 was among the two warmest years in the historical record. It featured a heat wave in Russia, all-time high temperatures in at least 17 countries, the hottest summer in New York City history, and devastating floods in Pakistan, China, Australia, the United States and other countries.
The immediate cause of the topsy-turvy weather is clear enough. A pattern of atmospheric circulation that tends to keep frigid air penned in the Arctic has weakened during the last two winters, allowing big tongues of cold air to descend far to the south, while masses of warmer air have moved north.
The deeper issue is whether this pattern is linked to the rapid changes that global warming is causing in the Arctic, particularly the drastic loss of sea ice. At least two prominent climate scientists have offered theories suggesting that it is. But others are doubtful ...
The uncertainty about what is causing the strange winters highlights a core difficulty of climate science.
Click the text to see the full article. Click the picture for a delightful 2010 "weather forecast" by the artist.