Shrinking sea could disrupt weather patterns

Posted by: Saving Water SA (Cape Town, South Africa) – partnered with Water Rhapsody conservation systems – 03 Sep 2011

Arctic sea ice cover has already shrunk to its third lowest level on record this year, in an irreversible trend that may see an ice-free summer around 2030, said the head of the world’s main monitoring centre.

The Arctic is on track to be completely ice-free in summer at some point this century

The sea ice area will be reduced further in the next two weeks but was unlikely to beat a 2007 retreat in a 32-year satellite data record, said Mark Serreze, director of the US-based National Snow and Ice Data Center.

While sea ice does not raise sea levels when it melts, just as melting ice in a glass of water, an ice-free summer would have implications for the exploitation of resources in the area, scientists say. It could also disrupt weather patterns or cause the Greenland ice sheet to melt more rapidly.

Exxon Mobil Corp and Rosneft signed an agreement on Tuesday to extract oil and gas from the Russian Arctic, in exploration which may be assisted by the recent trend of summer sea ice retreat north of Russia.

“The numbers today are saying that if all further melt stopped right now it would be the third most in the satellite record,” Serreze said today.

“We just dropped below 4.6 million square kilometres and that’s what we had in 2010 (at the minimum). We’re continuing the overall pattern of loss, and there’s still a couple of weeks to go in the melt season.” Continue reading

DDT comes in from the cold

Posted by: Saving Water SA (Cape Town, South Africa) – partnered with Water Rhapsody conservation systems – 25 July 2011

“Dirty Dozen” chemicals, including the notoriously toxic DDT, are being freed from Arctic sea ice and snow through global warming, a study published on Sunday suggested.

Before the dangers of DDT were known, crops and people were sprayed with the chemical to protect against bothersome insects.

The “Dirty Dozen” — formally known as persistent organic pollutants (POPs) — were widely used as insecticides and pesticides before being outlawed in 2001.

They are extremely tough molecules that take decades to break down in nature. They also bio-accumulate, meaning that as they pass up the food chain, concentrations rise, posing a fertility threat to higher species.

In addition, they are insoluble in water and easily revolatilise, so can swiftly transit from soil and water to the atmosphere in response to higher temperatures.

The study, published in the scientific journal Nature Climate Change, looked at atmospheric concentrations of three chemicals — DDT, HCH and cis-chlordane — monitored between 1993 and 2009 at a station in Norway’s Svalbard Islands and at another in the Canadian Arctic.

The scientists indeed found a long-term downward trend in primary emissions after the Stockholm Convention banned production and trade in the “Dirty Dozen.” Continue reading

Arctic ice decline sets June record

Posted by: Saving Water SA (Cape Town, South Africa) – partnered with Water Rhapsody conservation systems – 08 July 2010

The National Snow and Ice Data Centre reported yesterday (6 July 2010) that “in June, ice extent declined by 88,000 kilometres (34,000 square miles) per day, more than 50% greater than the average rate of 53,000 kilometres (20,000 square miles) per day. This rate of decline is the fastest measured for June.”  The average sea ice extent was the lowest for any June in the satellite record, which extends back to 1979.  The NSIDC reports in Rapid ice loss continues through June that the “linear rate of monthly decline for June over the 1979 to 2010 period is now 3.5% per decade.”

To put the situation in perspective:

  • The average Arctic Sea Ice extent was 1.29 million square kilometres (498,000 square miles) below the 1979 to 2000 average.  That departure from average is equivalent to the areas of California, Texas and Florida combined.
  • The daily decline in sea ice extent (averaging 88,000 kilometres or 34,000 square miles per day) was a daily decline greater than the area of South Carolina.

The NSIDC says that “weather conditions, atmospheric patterns, and cloud cover over the next month will play a major role in determining whether the 2010 sea ice decline tracks at a level similar to 2007,” the year when Arctic sea ice dropped to its lowest ever annual minimum extent.  The centre notes that an atmospheric pattern called the “summer Arctic dipole anomaly” has established itself over the region and favours winds that accelerate the decline in sea ice. The same pattern in 2007 was partly responsible for the record sea ice minimum observed in September of that year.

By: Nick Sundt
Source: WWF Climate Blog