Sea ice still declining, despite Antarctica’s gains | RenewEconomy

Sea ice still declining, despite Antarctica’s gains

Melting sea ice could have major impacts on regional and global weather and climate patterns, as well as sea life and wildlife.


Climate Central

When Antarctica grabbed headlines last year because of record-high sea ice levels circling the southernmost continent, it created confusion. Its increase was so at odds with the trend of dwindling sea ice, particularly in the Arctic, that it prompted those skeptical of the science of climate change to suggest it meant ocean ice is not disappearing.

Sea ice and meltwater ponds in the Arctic, as seen from the USCG Icebreaker Healy. Credit: Jeremy Potter NOAA/OAR/OER


But research shows that ice lost in the Arctic dwarfs any gains around Antarctica, as a recent study in the Journal of Climate clearly illustrates by combining satellite records of the two areas to produce a clear overall downward trend in sea ice.

“I hope that these results will make it clear that, globally, the Earth has lost sea ice over the past several decades, despite the Antarctic gains,” study author Claire Parkinson, a sea ice researcher at NASA’s Goddard Space Flight Center in Maryland, wrote in an email.

The inexorable decline of sea ice in the Arctic Ocean has been clear from the beginning of the satellite record in the late 1970s. Warming temperatures, fueled largely by climate change, have caused the ice to melt, creating patches of dark ocean water that absorb more of the sun’s rays and causing further warming and melting in a well-understood cycle. While melting sea ice doesn’t raise global sea levels like land ice does, it could have major impacts on regional and global weather and climate patterns, as well as sea life and wildlife.

The gains in Antarctica, in contrast, have emerged in the past few years and the causes aren’t well understood. Scientists are investigating, suspecting the leading culprits are changes to winds and ocean waters around the South Pole.

While scientists understand the Arctic loss far outweighs the Antarctic gains, the message hasn’t always been clear to the public, Parkinson said, which prompted her to do the study to enter the global trend into the official research record.

She used satellite records of the extent of sea ice at both poles and combined them to get the global trend, which mirrors the decline of the Arctic. The overall sea ice loss for the planet is about 13,500 square miles per year from 1979 to 2013.

Trends in sea ice extent, or area, in the Arctic, Antarctic and globally. Click image to enlarge. Credit: Joshua Stevens/NASA Earth Observatory

That decline was also seen in every calendar month, with the largest decline — of about 26,000 square miles per year — not surprisingly in September, when the Arctic hits its annual summer minimum.

The data shows the cycle of warming and melting is self-reinforcing, causing the global decline to accelerate. The ice has melted twice as fast from 1996 to the present as it did from 1979 to 1996.

“The paper conveys an important message that is often lost when climate change skeptics point to the increasing trend of sea ice in the Southern Hemisphere: The Arctic has lost much more sea ice than the Antarctic has gained. In other words, the planet as a whole is losing sea ice,” John Walsh, editor of the journal and a climate scientist at International Arctic Research Center at the University of Alaska Fairbanks, said in an email.

Julienne Stroeve, a sea ice researcher at the National Snow and Ice Data Center in Boulder, Colo., said the trends at each pole were less important than the overall impact of melting ice on the planet’s energy budget. The shift from an Arctic covered by white ice that reflects the sun’s rays to absorbent open ocean is much more important to that question than the more minor Antarctic increases.

Stroeve, who wasn’t involved in the study, also didn’t mind the interest in the Antarctic trends.

“The attention on the Antarctic ice growth is OK because as scientists we need to better understand the processes that have impacted Antarctic sea ice changes, so this creates more interest to do so,” she said.


Source: Climate Central. Reproduced with permission.

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  1. Polarbear 6 years ago

    Please explain to me, global temp has not risen 1 degree C, and the average temp at the poles are minus 30. so, since 1890 till now, the temp on the poles are minus 29C. now, ice melts at +4C, and not minus 29.

    • David Boxall 6 years ago

      Polarbear: clearly, a little knowledge is a dangerous thing

      • Polarbear 6 years ago

        Hi David, Thank you for the comment, but instead of making me feel like a fool, why don’t you explain to me why my question is so far off?
        Whether my freezer is set at minus 20 or minus 2, nothing defrosts until the ambient temperature of the area inside becomes at least 4 degrees C. (melting point of water)

        • David Boxall 6 years ago

          Is the water below sea ice liquid?

          • Polarbear 6 years ago

            yes it is a liquid, but due to the salt content, the actual temperature is much lower without freezing up? than clean water. why do you put salt on snowy roads? because salt water will NOT freeze if the temp drops below 0! I can see that you are enjoying my lack of knowledge, but hit me, I enjoy the challenge.

          • David Boxall 6 years ago

            As the globe warms, where has much of the heat gone?

          • Polarbear 6 years ago

            Warm air goes up,(unstoppable phenomenon) into the atmosphere which consists 78% nitrogen, 21% oxygen, and the other 1% is all the rest, including CO2. Now, how does CO2 make a “blanket” that prevents warm air from dissipating through it, while it only takes up 1% of the volume? if this 1% was CO2 only, (no Argon, Boron or any other gasses, the other 99% is still not stopping warm air from escaping? I flew at 24 000 feet last week and outside temp was -26. We hardly took off, then the temp was already minus. How does this 1% thin layer of CO2 form a chain that is so dense that no warm air can get through to cool down? I think we are being fed candy floss, we are to uninformed and un – influential to question authority.

          • David Boxall 6 years ago

            You clearly need to learn far more than I could ever teach. The site has been awarded for excellence in communicating complex climate science; it has also earned testimonials from eminent scientists. You’ll be hard pressed to find a more credible source of the information you need. If you’re truly interested in learning the science, then you might like to give it a go.

          • Polarbear 6 years ago

            Thank you, I will get back to you once I have studied this research. Now we are getting somewhere. I thank you for this.
            Glad I got your attention

        • Neil_Copeland 6 years ago

          Sea water doesn’t freeze until -1.8 degrees celsius due to the salt content.

    • onesecond 6 years ago

      You are talking about average temperature and at the poles. In the summer the arctic sea ice melts to a great extent and the sea ice moves. Basically in the summer melts more ice than what is added in the winter.

      • Austin Wonaeamirri 6 years ago

        That’s right, the hottest part of the year is the key element.

    • Ken Fabian 6 years ago

      North pole summer temperatures (air temp) average 0 degrees C – and last I heard that was the melting point of ice not +4 – and have reached as high as 5 degrees C. How can a polar bear not know that summer temperature in the Arctic, all the way to the pole, can and does exceed melting point of ice?

      The South pole doesn’t get above melting point but the edges of Antarctica certainly do and weakened edges of ice sheets allow glacial flow rates to increase – and ice, even unmelted, even without the lubrication of the base that is a consequence of surface melt, does flow.

      This article is about sea ice – stuff that grows out over water in winter and melts away in summer. Just as the increase in Antarctic winter sea ice is almost insignificant compared to the Arctic decrease, the overall changes to sea ice are almost insignificant compared to the continuing loss of mass of ice sheets (the ‘permanent’ ice over land), which is accelerating in Antarctica as well as Greenland.

      • Polarbear 6 years ago

        Thank you for the informative answer. This polar bear lives 1 500m above sea level, and water here boils at 96 C and not @100C.
        I was taught that ice here melts at +4degrees, (due to altitude.)
        but sea ice is at level. My concern is the following. In app 130 years, the average temp has increased steadily with less than one degree F, although the CO2 “revolution” has evolved from almost zero (in 1890) to millions of kilotons due to all the energy inventions in the past 100 years. If we are having such an effect on the globe, the graph should have stayed horizontal, until I’d guess, early eighties, as our energy output with vehicles and power stations etc., greatly multiplied since then. Yet the graph climbs slowly and constantly, so I am just asking, is this increase in global temp, not just a natural phenomenon, which is getting exploited to promote development of alternative energy sources, as we are going to run out of carbon resources in years to come?

        • David Boxall 6 years ago

          How vast a conspiracy does your belief necessitate?
          How probable is a conspiracy so vast?

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