Featured Research

from universities, journals, and other organizations

Arctic Sea Ice Shows "Striking" Decline Since 1960s

November 16, 1999
American Geophysical Union
The Arctic ice pack is around 40 percent thinner than it was 20-40 years ago, according to scientists who have studied data compiled by nuclear submarine cruises.

WASHINGTON -- Scientists using data acquired by U.S. Navy submarines have reported a "striking" reduction in the thickness of Arctic sea ice, as compared with 20-40 years ago. Writing in the December 1 issue of Geophysical Research Letters, Dr. D. Andrew Rothrock of the University of Washington, Seattle, and colleagues say the average draft of the sea ice (that is, its thickness from the ocean surface to the bottom of the ice pack) has declined by 4.3 feet (1.3 meters). This represents a reduction of about 40 percent as compared with the earlier period.

Related Articles

The decrease in sea ice occurs all across the Arctic Ocean and corresponds to previously reported evidence that the Arctic climate is warming, the researchers say. The sea ice data in the 1990s were acquired by the Scientific Ice Expeditions (SCICEX) program, which consisted of six extended cruises by nuclear submarines. This study analyzed data from three autumn cruises: by USS Pargo in 1993, USS Pogy in 1996, and USS Archerfish in 1997.

The SCICEX cruises covered most of the deep Arctic Ocean basin. Measurements of the sea ice thickness showed a perennial ice cover of from 3 to 9 feet (1-3 meters) in mean draft, which was considerably thinner than previous estimates. The earlier data, used for comparison, began with the first nuclear submarine, USS Nautilus, in 1958 and continued through a cruise of HMS Sovereign in 1976. Data from the earlier cruises were adjusted as necessary for the time of year they took place, to correspond with the autumn data acquired in the 1990s. There are few data available from the 1976-1993 period. The researchers conservatively estimate the overall errors in measurement as less than one foot (0.3 meters).

Rothrock writes that the changes from the earlier period to the present are "striking in the uniformity of their sign and in their magnitudes." That is, every one of the 29 sites compared between the earlier cruises and those of the 1990s showed a decline in ice thickness. In certain areas, such as the Nansen Basin and the eastern Arctic, the thinning is over five and a half feet (1.7 meters). Elsewhere, such as the Beaufort Sea and Chukchi Cap, it is around three feet (one meter), and at the North Pole and in the Canada Basin the decrease lies between those extremes. However, the researchers note, this is not an instance of ice thinning in one area while thickening in another, which could be induced by a change in surface wind patterns.

The researchers say the available data are insufficient to provide answers about the cause of the ice loss. They suggest several hypotheses about the flow of heat from the ocean itself, from the atmosphere, and from shortwave radiation. Other avenues to be explored include the amount of precipitation and snow cover in the region and ice movement.

A key topic for future research is whether ice volume has reached a minimum in a multi-decadal cycle or whether the decline will continue into the future. Regardless, the researchers say, the thinning of Arctic ice that has already occurred is "a major climatic signal that needs to be accounted for in a successful theory of climate variability." To help fill the gaps between the earlier and more recent submarine observations, they call for the public release of other ice thickness data gathered by submarines over the past 40 years, which they believe would be "of immense help" in refining this climatic signal.

The study was funded by the National Science Foundation, the Office of Naval Research, and NASA.


Story Source:

The above story is based on materials provided by American Geophysical Union. Note: Materials may be edited for content and length.

Cite This Page:

American Geophysical Union. "Arctic Sea Ice Shows "Striking" Decline Since 1960s." ScienceDaily. ScienceDaily, 16 November 1999. <www.sciencedaily.com/releases/1999/11/991115145020.htm>.
American Geophysical Union. (1999, November 16). Arctic Sea Ice Shows "Striking" Decline Since 1960s. ScienceDaily. Retrieved December 27, 2014 from www.sciencedaily.com/releases/1999/11/991115145020.htm
American Geophysical Union. "Arctic Sea Ice Shows "Striking" Decline Since 1960s." ScienceDaily. www.sciencedaily.com/releases/1999/11/991115145020.htm (accessed December 27, 2014).

Share This

More From ScienceDaily

More Earth & Climate News

Saturday, December 27, 2014

Featured Research

from universities, journals, and other organizations

Featured Videos

from AP, Reuters, AFP, and other news services

Nevada Farmer Uses Goats to 'recycle' Christmas Trees

Nevada Farmer Uses Goats to 'recycle' Christmas Trees

Reuters - US Online Video (Dec. 27, 2014) A Nevada goat farmer partners up with a local fire department to 'recycle' discarded Christmas trees. Mana Rabiee reports. Video provided by Reuters
Powered by NewsLook.com
Christmas Trees And Bugs Are Seemingly Symbiotic

Christmas Trees And Bugs Are Seemingly Symbiotic

Newsy (Dec. 24, 2014) The National Christmas Tree Association says bugs in trees are a relatively small problem, but recommends giving your tree a good shake anyway. Video provided by Newsy
Powered by NewsLook.com
Ukrainian Coal Miners Work to Stave Off Electricity Shortage

Ukrainian Coal Miners Work to Stave Off Electricity Shortage

AFP (Dec. 24, 2014) Coal miners in the separatist east of Ukraine work to ensure there won't be electricity shortages during the coldest months of winter, but the country has declared a state of emergency in its electricity market. Duration: 00:59 Video provided by AFP
Powered by NewsLook.com
Uruguay Chooses 'smart' Farming Methods for Ambitious Goals

Uruguay Chooses 'smart' Farming Methods for Ambitious Goals

AFP (Dec. 24, 2014) Using GM crops, genetically chosen cows, and technology like satellites and drones, Uruguay - with a population of just 3 million people - is aiming to produce enough food to feed 50 million. Duration: 03:10 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.


Breaking News:

Strange & Offbeat Stories

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News


Free Subscriptions

Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile

Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?

Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins