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Climate studies probe growth of Antarctic sea ice

‘The planet as a whole is doing what was expected in terms of warming. Sea ice as a whole is decreasing as expected …’

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Sea ice is expanding around Antarctica, and scientists say wind, snow and melting land ice are key factors in the growth bberwyn photo.

The map at right shows Antarctic ice concentration on September 22, 2014, the date of the record high. Areas where the surface was less than 15% ice covered are deep blue; areas that were up to 100% ice covered are shades of light blue to white. The orange line shows the 1981-2010 median extent for September 22. (Median means in the middle: half of the years in the record had smaller ice extents than this, and half had larger extents.) The graph below the map shows daily Antarctic sea ice extent over the course of the year. The black line traces the 1981-2010 average, and the gray shading shows the range of variability (2 standard deviations from the mean). The previous record high extent (2013) is a dashed green line; the 2014 year to date is a light green line. NSIDC reported that the 2014 extent rose nearly 4 standard deviations above the 1981-2010 mean.

The map above shows Antarctic ice concentration on September 22, 2014, the date of the record high. Areas where the surface was less than 15% ice covered are deep blue; areas that were up to 100% ice covered are shades of light blue to white. The orange line shows the 1981-2010 median extent for September 22. (Median means in the middle: half of the years in the record had smaller ice extents than this, and half had larger extents.)
The graph below the map shows daily Antarctic sea ice extent over the course of the year. The black line traces the 1981-2010 average, and the gray shading shows the range of variability (2 standard deviations from the mean). The previous record high extent (2013) is a dashed green line; the 2014 year to date is a light green line. NSIDC reported that the 2014 extent rose nearly 4 standard deviations above the 1981-2010 mean. Courtesy NOAA.

By Summit Voice

FRISCO — Along with shifting wind patterns in the southern hemisphere, melting land ice may be contributing to recent record extents of floating sea ice around Antarctica. The melting ice and snow adds fresh water — which freezes morel easily — to the salty Southern Ocean, scientists said in a release this week, explaining the multi-year trend of expanding Antarctic sea ice.

But the increase doesn’t balance the loss of sea ice at the other end of the Earth. Arctic sea ice has declined by an average of 20,800 square miles per year; the Antarctic has gained ice at a rate of about a third of that, by an average of 7,300 square miles per year.

This week, the National Snow and Ice Data Center (NSIDC) reported that Antarctic sea ice extent set a new record high for daily extent: 20.11 million square kilometers (7.76 million square miles), the highest since satellite observations started in the late 1970s.

In July, a European study called into question the recent measurements, citing inconsistencies in computer models.

Other studies suggest the growth is only temporary, and that Antarctic sea ice will ultimately decline dramatically in the decades ahead.

The ice trackers matched this year’s late season ice surge with strong southerly winds blew over the Weddell Sea. Without any nearby land masses to constrain growth, those winds tend to push the ice northward. Continue reading

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Climate: Polar paradox?

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September trend for Arctic sea ice extent is down, down, down. Courtesy NSIDC.

Arctic sea ice bottoms out; Antarctic sea ice hits new high

Staff Report

FRISCO — Even without remarkably warm weather patterns across the Arctic, summer sea ice dropped to the sixth-lowest extent on record this year, while at the other end of the Earth, sea ice around Antarctica swelled to a record extent.

Through 2014, Arctic sea ice has now been declining at a rate of 13.3 percent per decade relative to the 1981 to 2010 average. The ten lowest September ice extents over the satellite record have all occurred in the last ten years. Continue reading

Climate: Study sheds new light on Antarctic sea ice expansion

Growth in sea ice may be slower than reported

The water in the Antarctic Sound can be smooth as glass, and sometimes look thick and oily, probably because it's so cold. Click on the photo to learn about some of the environmental issues in Antarctica.

Scientists are puzzling over the expansion of Antarctic sea ice. bberwyn photo.

Staff Report

FRISCO — Global warming deniers have long been using the observed expansion of Antarctic sea ice as a way to try and confuse the public about the reality of global warming, but some new research by scientists with the Scripps Institution of Oceanography at University of California San Diego suggests the rate of expansion is not as dramatic as reported.

The findings, published in The Cryosphere (European Geosciences Union) acknowledge that there has been some expansion recently, but that some of the reported ice gain may be due to inconsistencies in computer models used to measure Antarctic sea ice. Continue reading

Study projects major decline of Antarctic sea ice

Meltdown likely to have serious impacts on marine life

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How long will Antarctic sea ice persist? bberwyn photo.

Staff Report

*Adapted from a Virginia Institute of Marine Science press release. More Summit Voice stories on sea ice here.

FRISCO — While global warming deniers try to divert attention from the building climate crisis by pointing at record-high Antarctic sea ice extent, a new study suggests much of that ice will soon melt away.

Plugging projected increases in Antarctic air temperatures into finely scaled models, the scientists said the Ross Sea could lose more than half its summer ice by 2050 and more than 75 percent by 2100. Continue reading

Study shows links between Atlantic Ocean warming and changing climate in Antarctica

Findings may help explain changes in Antarctic sea ice patterns

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The Antarctic Peninsula is warming twice as fast as most other regions.

By Summit Voice

FRISCO — A team of New York University scientists say they’ve found potential links between gradual warming of the North and Tropical Atlantic Ocean and climate changes in Antarctica.

The researchers reached their findings after carefully analyzing 30 years of data, helping to show how distant regional conditions are contributing to Antarctic climate change and redistribution of Antarctic sea ice.

“Our findings reveal a previously unknown, and surprisingm force behind climate change that is occurring deep in our southern hemisphere: the Atlantic Ocean,” said Xichen Li, a doctoral student in NYU’s Courant Institute of Mathematical Sciences and the study’s lead author. “Moreover, the study offers further confirmation that warming in one region can have far-reaching effects in another.” Continue reading

Climate: Arctic sea ice stays below average in February

Downward trend continues …

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Antarctic sea ice was above normal in February and throughout the southern hemisphere summer, but that doesn’t balance the losses in Arctic sea ice, according to climate scientists. This NASA image shows ice in the Weddell Sea. Visit this NASA Earth Observatory web page for more information on Antarctic sea ice.

By Summit Voice

FRISCO — With the spring equinox approaching, Arctic sea ice is nearing its maximum seasonal extent for the year, and the National Snow and Ice Data Center is reporting that there is no sign of any significant rebound in ice extent from the record-low levels of the last couple of years.

The average February Arctic sea ice extent has been declining at rate of 2.9 percent per decade since 1979, resulting in an overall decline of more than 1.57 million square kilometers (606,000 square miles) from 1979 to 2013. Read the full NSIDC report here. Continue reading

Climate: Shifting winds drive Antarctic sea ice changes

New study pinpoints regional growth and decline of Antarctic sea ice

Researchers are starting to understand how shifting wind patterns are driving changes in Antarctic sea ice extent. Bob Berwyn photo.

By Bob Berwyn

FRISCO — After compiling more than 5 million individual daily ice motion measurements of sea ice motion around Antarctica, scientists from the U.S. and U.K. say they’re sure that the recent increases in Antarctic sea ice are linked to changing wind patterns in the region.

Essentially, the circumpolar winds are strengthening around Antarctica, said Dr. Ron Kwok, of NASA’s Jet Propulsion Laboratory in California. Why those winds are intensifying, and whether it’s linked with a warming atmosphere remains as a huge question, Kwok said. View a mult-year animation of Antarctic sea ice changes here.

“We are basically finding evidence of change over a long time scale … That’s why it’s inportant to quantify the mechanisms,” he said. “It’s probably associated with a changing climate. The Antarctic sea ice interacts with the global climate system very differently than that of the Arctic, and these results highlight the sensitivity of the Antarctic ice coverage to changes in the strength of the winds around the continent.” Continue reading

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