Record-low Arctic ice melt in 2012 linked to man-made climate change: new report

“the extremely low Arctic sea ice extent in summer 2012″ resulted primarily from the melting of younger, thin ice from a warmed atmosphere and ocean, says a new report. (PHOTO BY JANE GEORGE)

A new report on 12 of 2012’s most extreme weather events says man-made global warming is “having an impact on some extreme weather and climate events.”

This is the second year that the National Oceanic and Atmospheric Administration and the British meteorology office have looked at the previous year’s exteme weather events.

In “Explaining Extreme Events of 2012 from a Climate Perspective” published Sept. 5 in the Bulletin of the American Meteorological Society, 78 research said climate change made,a record-low Arctic sea ice extent, drought in Europe, heat waves and flooding in the U.S. and extreme rainfalls in Australia and New Zealand more probable.

Overall, 78 researchers in 18 different research teams from around the world contributed to the report that examined the causes of 12 extreme events which took place on five continents and in the Arctic during 2012.

Their report concludes that natural weather cycles and climate ups-and-downs played “a key role in the intensity and evolution” of the 2012 extreme events.

But, in some events, their analyses revealed “compelling evidence” that human-caused climate change, through the emission of heat-trapping greenhouse gases, also contributed to the extreme event.

“This report adds to a growing ability of climate science to untangle the complexities of understanding natural and human-induced factors contributing to specific extreme weather and climate events,” said Thomas R. Karl, director of NOAA’s National Climatic Data Center in a news release on the report. “Nonetheless, determining the causes of extreme events remains challenging.”

To that end, researchers carried out multiple analyses of four of the events — warm temperatures in the United States, record-low levels of Arctic sea ice, and heavy rains in northern Europe and eastern Australia — and came up with similar conclusions.

As for “the extremely low Arctic sea ice extent in summer 2012,” the report says this resulted primarily from the melting of younger, thin ice from a warmed atmosphere and ocean.

“This event cannot be explained by natural variability alone. Summer Arctic sea ice extent will continue to decrease in the future, and is expected to be largely absent by mid-century.”

In December 2012, NOAA produced its annual Arctic “report card” for 2012.

That report pointed to evidence of “Arctic environmental system change,” with NOAA saying that the record-breaking year set troubling pattern.