Nav: Home

Reconstruction of Arctic Barents-Kara sea ice extent changes over the last millennium

July 19, 2018

Under the background of global warming, temperature in the Arctic has increased more significantly than the global average. However, winter extreme cold events in Eurasia including China have become frequent in recent years. This trend is obviously contrary to the global warming. You may still remember that the severe weathers with cold surge, ice-snow and frozen rain occurred in southern China in 2008 and the overwhelming "boss-level" cold wave that attacked almost the whole China in 2016, which both caused heavy casualties and property losses. Several scholars believe that these events are closely related to the rapid decline of the Arctic sea ice.

The Barents-Kara Sea is considered to be one of the cradles for cold waves over the Eurasian continent, and it is a key sea sector that is closely connected with cold waves over Eurasia. Studies have shown that when the Barents-Kara sea ice extent is relatively small during autumn and winter, extreme cold wave events are more likely to occur during the winter over Eurasia.

However, controversies still exist. Some scholars believe that the frequent occurrence of extreme cold events over mid-latitudes in the Northern Hemisphere in recent years are ascribed to the internal variability of atmospheric circulation, and they are not significantly related to the decrease in Arctic sea ice.

One of the main reasons for this controversy is that the length of the Arctic sea ice satellite observation data is limited regarding the analysis of changes and causes of Arctic sea ice on a long-term timescale, which severely constrains our understanding of the natural variability in Arctic sea ice and its correlation with frequent extreme cold events that occur over mid-latitudes. Therefore, it is very necessary to recover the Arctic sea ice time series before the instrumental period and analyze its variations on a longer timescale.

A recent study used reliable mathematical methods combined with high-quality climate proxy data to recover the long time series of Arctic Barents-Kara Sea ice extent and found that human activities since the industrial revolution have greatly contributed to the decline of Arctic sea ice. An article related to this study was just published in the Science China Earth Sciences, with Cunde Xiao, scientist at the Beijing Normal University, as the corresponding author.

After intercomparing the results and statistical parameters using the ordinary least squares regression, the principle component regression and the partial least squares regression methods, SIE time series were synthesized into a more robust series as the final result by the researchers. It's showed that the Barents-Kara sea ice began to decrease significantly at the end of the 18th century, and a shrinking trend became much more significant during the second half of the 19th century. Even though the sea ice had a short period of expansion during 1940s-1970s. However, it continuously and significantly shrank after 1970s. The reduction sea ice in this area after the end of the 18th century was unprecedented in both duration and speed over the last 700 years. The industrial revolution may be a dominant factor in this result. The Arctic SIE in recent years may be the lowest it has been over the last millennium.

However, sea ice is a complex component in the climate system. Its variation is affected by many factors, such as temperature, atmospheric circulation, and ocean current, and its mechanisms of its evolution are extremely complex. It is necessary to integrate paleoclimate reconstruction methods with numerical models and machine learning algorithms under the background of the big data era to further improve the results. In addition, we have reconstructed the sea ice extent in the Barents-Kara Sea sector, which is sensitive to triggering extreme cold waves over Eurasia. The changes and interactions in Arctic sea ice between different sea sectors are more important. In the future, we need to collect more high-quality proxy data to reconstruct the sea ice in the entire Arctic region and the different sea sectors.
This research was supported by the National Natural Science Foundation of China (NSFC, 41425003), the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA19070103), the Basic Research Project of Chinese Academy of Meteorological Sciences-Base Construction of Polar Atmospheric Sciences for Field Observation, and the Scientific Research Foundation of the Key Laboratory of Cryospheric Sciences (SKLCS-OP-2016-03).

See the article:

Zhang Q, Xiao C D, Ding M H, Dou T F. 2018. Reconstruction of autumn sea ice extent changes since AD1289 in the Barents-Kara Sea, Arctic. Science China Earth Sciences,

This article was published online:

Science China Press

Related Global Warming Articles:

A new study provides a solid evidence for global warming
The new study allows a more accurate assessment of how much heat has accumulated in the ocean (and Earth) system.
Global warming hiatus disproved -- again
UC Berkeley scientists calculated average ocean temperatures from 1999 to 2015, separately using ocean buoys and satellite data, and confirmed the uninterrupted warming trend reported by NOAA in 2015, based on that organization's recalibration of sea surface temperature recordings from ships and buoys.
Report reassesses variations in global warming
Experts at the European Centre for Medium-Range Weather Forecasts (ECMWF) have issued a new assessment of temperature trends and variations from the latest available data and analyses.
Clouds are impeding global warming... for now
Lawrence Livermore National Laboratory researchers have identified a mechanism that causes low clouds -- and their influence on Earth's energy balance -- to respond differently to global warming depending on their spatial pattern.
Global warming's next surprise: Saltier beaches
Batches of sand from a beach on the Delaware Bay are yielding insights into the powerful impact of temperature rise and evaporation along the shore that are in turn challenging long-held assumptions about what causes beach salinity to fluctuate in coastal zones that support a rich network of sea creatures and plants.
Could global warming's top culprit help crops?
A new study tries to disentangle the complex question of whether rising amounts of carbon dioxide in the air might in some cases help crops.
Evaporation for review -- and with it global warming
The process of evaporation, one of the most widespread on our planet, takes place differently than we once thought -- this has been shown by new computer simulations carried out at the Institute of Physical Chemistry of the Polish Academy of Sciences in Warsaw.
Researchers reveal when global warming first appeared
Human caused climate change is increasingly apparent today through multiple lines of evidence.
1,800 years of global ocean cooling halted by global warming
Prior to the advent of human-caused global warming in the 19th century, the surface layer of Earth's oceans had undergone 1,800 years of a steady cooling trend, according to a new study in the Aug.
Global sea levels have risen 6 meters or more with just slight global warming
A new review analyzing three decades of research on the historic effects of melting polar ice sheets found that global sea levels have risen at least six meters, or about 20 feet, above present levels on multiple occasions over the past three million years.

Related Global Warming Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#SB2 2019 Science Birthday Minisode: Mary Golda Ross
Our second annual Science Birthday is here, and this year we celebrate the wonderful Mary Golda Ross, born 9 August 1908. She died in 2008 at age 99, but left a lasting mark on the science of rocketry and space exploration as an early woman in engineering, and one of the first Native Americans in engineering. Join Rachelle and Bethany for this very special birthday minisode celebrating Mary and her achievements. Thanks to our Patreons who make this show possible! Read more about Mary G. Ross: Interview with Mary Ross on Lash Publications International, by Laurel Sheppard Meet Mary Golda...