Environmental News 23/01/2012
Global Warming: 'Revenge of the atmosphere'
Rutgers researcher identifies links between Arctic warming, mid-latitude weather patterns. With Arctic sea ice shrinking fast - losing 40 percent of its mass between 1980 and 2007 - widespread effects on climate and weather are inevitable, according to Jennifer Francis, with Rutgers University Institute of Marine and Coastal Sciences. "How can it not affect the weather? It's such a huge loss in the Earth's system," Francis said, speaking Jan. 13 and the Glenn Gerberg Weather and Climate Summit in Breckenridge, Colorado. Discussing the link between rapid climate changes in the Arctic and weather patterns in mid-latitudes, Francis said her most recent research points to a direct link between changes over the Arctic and mid-latitude weather patterns driven by the jet stream. The Arctic is warming twice as fast as other parts of the Earth and essentially, that heat is changing air pressure gradients and reducing the speed of circumpolar winds. That leads to a greater amplification of the high pressure ridges and low pressure troughs in mid-latitudes. As those kinks in the atmospheric circulation grow more pronounced, it slows the progression of weather systems moving from west to east around the northern hemisphere, allowing weather systems to get stuck over certain regions. Speaking to an audience of TV meteorologists, Francis called it the "revenge of the atmosphere," then explained some of the recent changes in the Arctic. "When the ice was thick in the good old days ... the variations we saw were caused by wind, moving the ice around a bit. The winds would change, the ice didn't respond so much ... now that it's thinner, it moves around more," she said. Some of the biggest shifts came during a lengthy positive phase of the Arctic Oscillation during the 1990s, when more Arctic ice was transported directly into the Arctic Ocean, leaving the high Arctic filled with younger and thinner ice, she said. The end result is that, instead of thick, long-lasting ice reflecting incoming solar energy back into space, the heat is absorbed by the darker colored water.
Enthusiastic youngsters keep a lid on beach rubbish
Fifteen sunscreened children assemble on the banks of the Hawkesbury River. Do they know why they're here? "Cos of the turtles!" shouts Francis Pearce, 13, raising his hands to his blond head to contain the excitement. Graham Johnston runs weekly patrols to clean up the river and remove dangers to wildlife, staffed exclusively with children from schools and youth centres around Sydney and the central coast. The idea struck him two years ago after collecting litter on a camping trip. "We ended up with that much we had to call in for backup," Mr Johnston says. The group divides into three red motorised dinghies and sets off on patrol. The small strip of beach at Dead Horse Bay is deserted except for an old wooden barge converted into a ramshackle houseboat, with milk crates and wind chimes, a bobbling bohemian rebuke to the collection of 10-metre yachts docked 50 metres away. The children scream excitedly as they run around collecting rubbish: bottles, a fractured plastic bucket and an enormous decaying beach umbrella. Under the weight of unspoken admonishment, the family on the houseboat sheepishly begins helping too.
Huge pool of Arctic water could cool Europe: study
A huge pool of fresh water in the Arctic Ocean is expanding and could lower the temperature of Europe by causing an ocean current to slow down, British scientists said Sunday. Using satellites to measure sea surface height from 1995 to 2010, scientists from University College London and Britain's National Oceanography Center found that the western Arctic's sea surface has risen by about 15 cms since 2002. The volume of fresh water has increased by at least 8,000 cubic km, or about 10 percent of all the fresh water in the Arctic Ocean. The fresh water comes from melting ice and river run-off. The rise could be due to strong Arctic winds increasing an ocean current called the Beaufort Gyre, making the sea surface bulge upwards. The Beaufort Gyre is one of the least understood bodies of water on the planet. It is a slowly swirling body of ice and water north of Alaska, about 10 times bigger than Lake Michigan in the United States. Some scientists believe the natural rhythms of the gyre could be affected by global warming which could have serious implications for the ocean's circulation and rising sea levels. Climate models have suggested that wind blowing on the surface of the sea has formed a raised dome in the middle of the Beaufort Gyre, but there have been few in-depth studies to confirm this. If the wind changes direction, which happened between the mid-1980s to mid-1990s, the pool of fresh water could spill out into the rest of the Arctic Ocean and even into the north Atlantic Ocean, the study said.