By Jim Steele

From 1979 to 2015, the extent of Antarctic sea ice increased, defying climate model predictions and alarmists’ expectation (graph A-1). Then a sudden sea ice decrease in 2016 got the doomsayers to celebrate. The NY Times headlined “Antarctic Sea Ice Is at a ‘Very Concerning’ Record Low”. Likewise National Public Radio’s “Antarctica has a lot less sea ice than usual. That’s bad news for all of us”. The alarmist propaganda site, The Conversation, characterized the decrease as catastrophic: “Devastatingly low Antarctic sea ice may be the ‘new normal’ and “will have serious implications for Southern Ocean ecosystems and global consequences for the climate system.”

But the EPA’s graph (A-2), showing total sea ice change, and doesn’t narrowly zoom in on the y-axis, and reveals an insignificant sea ice trend. The maximum extent of Antarctica sea ice extent has hovered for decades around 7 million square miles, while ~86% rapidly melts each summer to an average minimum of 1 million square miles. In contrast, Arctic sea ice only reaches a maximum of about 4.7 million square miles each winter, but only 65% melts each summer. Because Antarctica’s sea-ice extent is driven by very different dynamics than Arctic sea ice, any averaging that combines the 2 poles into a global sea ice trend is totally worthless for scientifically understanding the causes of sea ice change. It is only useful for pushing propaganda of a global climate crisis!

Despite alarmists’ blather about serious ecosystem consequences, the opposite is true. Emperor penguin’s (B) populations have increased, from an estimated 595,000 in 2012, growing to as many as 650,000 by 2023. When Emperor penguins must march too far to reach open water to feed in the winter, they abandon those breeding sites. Similarly, normal summer minimums (C) leave much of the Antarctic coast measurably ice free, which is ideal for Adelie penguins, who will abandon their summer breeding sites whenever there is too much coastal sea ice and delays their access to open water.

The rapid loss of Antarctic sea-ice each summer is a function of how its thinner sea ice is formed. Cold winds, sometimes as low as -25°C, blowing from Antarctica’s interior, initiate the formation of millimeter sized ice crystals known as “frazil ice” (E). During weather with calm winds, frazil ice may congeal into a soupy layer of ice. Otherwise it is typically blown away from the coast where it congeals into various sized “pancakes” of ice (F) forming a mosaic of ice floes and open water.

Actual amounts of sea ice are difficult to accurately measure because satellites can only measure sea ice concentrations of 15% or more. Depending on the strength and direction of the winds, despite below freezing temperatures, sea ice concentrations will decrease where strong winds disperse the ice, sometimes creating vast stretches of open water, called polynyas, that are vital to breeding Emperor penguins and the regional ecosystem.

As seen in graphic (G), winds and currents can also compress and thicken the sea ice as it does along the east coast of the Antarctic peninsula. In that location, sea ice remains all summer. However, in most locations the process of sea ice transport creates a layer of relatively thin first-year ice that rapidly melts each summer with small pockets of compressed ice that survive summer melt. The thinnest ice and most easily melted ice (blues and purple of G) are located at Antarctica’s distant perimeter where Antarctica’s sea ice extent is defined.

Lastly, changing strengths of the quasi-permanent low-pressure systems that encircle Antarctica can cause increased sea ice extent in one region, while compressing ice and decreasing extent in another. Graphic (H) is a screenshot from the US weather model’s website for June 2016. The dark areas show low pressure systems with the lowest pressures illustrated in red. Low pressure systems in the southern hemisphere cause winds to circulate in a clockwise fashion. The added red arrows on the Amundsen Low exemplify low-pressure system’s circulation causing northerly winds blowing towards the coast on its eastern flank, and southerly winds blowing away from the coast on its western flank.

Wang et al (2023)’s peer reviewed paper “Contribution of the deepened Amundsen Sea Low (ASL) to the record low Antarctic sea-ice extent in February 2022” eloquently explains how these low-pressure systems affect wind direction and sea ice extent. When ASL pressure deepens, the associated southerly winds strengthen and accelerates sea ice export away from the coast and expands the Ross Sea’s open water polynyas. More open water in the summer allows greater solar heating and increases summer melt. Furthermore, changes in the ASL strength correlate with natural El Nino and La Nina effects.

As Holland & Kwok (2012) wrote in the peer-reviewed Wind-driven trends in Antarctic sea-ice drift, it is sea ice motion driven by the winds is “is largely responsible for the size and shape of the Antarctic ice cover.”

Antarctic sea ice changes have nothing to do with global warming. Ignore alarmists’ media hype and learn some science. Don’t be a climate moron!