Humans Responsible for Half of Arctic Ice Loss, Study Says

New research indicates that Arctic sea ice may temporarily stabilize or expand over the next few decades after its rapid retreat that saw a historical peak in July. Arctic ice has been declining since the start of satellite monitoring in 1979, and half of the trend is attributed to human activity, the study also revealed.

National Oceanographic and Atmospheric Administration (NOAA) reported Arctic ice levels plunged to a record low, resulting in the seventh warmest July since 1880.

While scientists warned just a few years ago that the Arctic could lose its summertime ice cover by the end of the century, some research has indicated that Arctic summers could be largely ice-free within the next several decades.

A computer modeling study by the National Center for Atmospheric Research (NCAR) research team reinforced the fact that human-made global warming is to be blamed for around half the recent record loss of Arctic ice.

Lead author Jennifer Kay, a staff scientist at NCAR explained that the study attempted to learn how much of the melting ice can be attributed to natural variability by nonhuman forces and how much has been caused by greenhouse gases such as carbon dioxide and by atmospheric particulates.

"There's no doubt about it -- sea ice is going away," Kay said. "What we found was that about half of that trend is related to the increasing greenhouse gases."

The study indicated that the year-to-year and decade-to-decade trends in the extent of sea ice are likely to fluctuate increasingly as temperatures warm and the ice thins. Surprisingly, the current climate conditions provide Arctic ice with equal chances to expand as well as contract.

"One of the results that surprised us all was the number of computer simulations that indicated a temporary halt to the loss of the ice," said Kay.

"The computer simulations suggest that we could see a 10-year period of stable ice or even a slight increase in the extent of the ice."

Despite the new insights, more modeling studies and longer-term observations are necessary for a better understanding of how climate change and weather variability affect Arctic ice.

"Even though the observed ice loss has accelerated over the last decade, the fate of sea ice over the next decade depends not only on human activity but also on climate variability that cannot be predicted."

Scientists say the waning of sea ice, which is caused by weather changes, will in turn lead to even more climate warming. The loss of summer sea ice is already affecting the land and people near the Arctic Ocean. Scientists have been worried over the declining trend of arctic sea ice, which plays a crucial role in global climate.

"As we learn more about climate variability, new and unexpected research results are coming to light," says Sarah Ruth, program director in the Division of Atmospheric and Geospace Sciences, which funds NCAR. "What's needed now are longer-term observations to better understand the effect of climate change on Arctic sea ice."