On Feb. 24, Andy May told Watts Up With That? readers that:
"Antarctic sea-ice is also growing this year with respect to last year, so global sea-ice extent is going to see an important jump this year."
Yesterday, the following appeared in Proceedings of the National Academy of Science:
A 40-y record reveals gradual Antarctic sea ice increases
followed by decreases at rates far exceeding
the rates seen in the Arctic
A newly completed 40-y record of satellite observations is used to quantify changes in Antarctic sea ice coverage since the late 1970s. Sea ice spreads over vast areas and has major impacts on the rest of the climate system, reflecting solar radiation and restricting ocean/atmosphere exchanges. The satellite record reveals that a gradual, decades-long overall increase in Antarctic sea ice extents reversed in 2014, with subsequent rates of decrease in 2014–2017 far exceeding the more widely publicized decay rates experienced in the Arctic. The rapid decreases reduced the Antarctic sea ice extents to their lowest values in the 40-y record, both on a yearly average basis (record low in 2017) and on a monthly basis (record low in February 2017).
Abstract
Following over 3 decades of gradual but uneven increases in sea ice coverage, the yearly average Antarctic sea ice extents reached a record high of 12.8 × 106 km2 in 2014, followed by a decline so precipitous that they reached their lowest value in the 40-y 1979–2018 satellite multichannel passive-microwave record, 10.7 × 106 km2, in 2017. In contrast, it took the Arctic sea ice cover a full 3 decades to register a loss that great in yearly average ice extents. Still, when considering the 40-y record as a whole, the Antarctic sea ice continues to have a positive overall trend in yearly average ice extents, although at 11,300 ± 5,300 km2⋅y−1, this trend is only 50% of the trend for 1979–2014, before the precipitous decline. Four of the 5 sectors into which the Antarctic sea ice cover is divided all also have 40-y positive trends that are well reduced from their 2014–2017 values. The one anomalous sector in this regard, the Bellingshausen/Amundsen Seas, has a 40-y negative trend, with the yearly average ice extents decreasing overall in the first 3 decades, reaching a minimum in 2007, and exhibiting an overall upward trend since 2007 (i.e., reflecting a reversal in the opposite direction from the other 4 sectors and the Antarctic sea ice cover as a whole).
Since the late 1990s, it has been clear that the Arctic sea ice cover has been decreasing in extent over the course of the multichannel passive-microwave satellite record begun in late 1978 (1⇓–3). The decreases have accelerated since the 1990s and have been part of a consistent suite of changes in the Arctic, including rising atmospheric temperatures, melting land ice, thawing permafrost, longer growing seasons, increased coastal erosion, and warming oceans (4, 5). Overall, it has been a consistent picture solidly in line with the expectations of the warming climate predicted from increases in greenhouse gases. In particular, modeled sea ice predictions showed marked Arctic sea ice decreases, and the actual decreases even exceeded what the models predicted (6).
STAY TUNED FOR GARGLING NOISES FROM CONTRARIAN READERS OF
Strong Arctic sea-ice growth this year | Watts Up With That?
STAY TUNED FOR GARGLING NOISES FROM CONTRARIAN READERS OF
Strong Arctic sea-ice growth this year | Watts Up With That?
"Antarctic sea ice grew from 1979 to its peak year of 2014, while Arctic sea ice declined from 1979 to 2012."
STRAWMAN ALERT!!!! Arctic ice is floating on water, Antarctic ice is land bound....".
STRAWMAN ALERT!!!! Arctic ice is floating on water, Antarctic ice is land bound....".
