Scientists struggle to understand why Antarctica hasn’t warmed in over 70 years despite rise in CO2
by Chris Morrison
Scientists are scrambling to explain why the continent of Antarctica has shown Net Zero warming for the last seven decades and almost certainly much longer. The lack of warming over a significant portion of the Earth undermines the unproven hypothesis that the carbon dioxide humans add to the atmosphere is the main determinant of global climate.
Under ‘settled’ science requirements, the significant debate over the inconvenient Antarctica data is of necessity being conducted well away from prying eyes in the mainstream media. Promoting the Net Zero political agenda, the Guardian recently topped up readers’ alarm levels with the notion that “unimaginable amounts of water will flow into oceans”, if temperatures in the region rise and ice buffers vanish. The BBC green activist-in-chief Justin Rowlatt flew over parts of the region and witnessed “an epic vision of shattered ice”. He described Antarctica as the “frontline of climate change”. In 2021, the South Pole had its coldest six-month winter since records began in 1957, a fact largely ignored in the mainstream. One-off bad weather promoter Reuters subsequently ‘fact checked’ commentary on the event in social media. It noted that a “six-month period is not long enough to validate a climate trend”.
A recent paper from two climate scientists (Singh and Polvani) accepts that Antarctica has not warmed in the last seven decades, despite an increase in the atmospheric greenhouse gases. It is noted that the two polar regions present a “conundrum” for understanding present day climate change, as recent warming differs markedly between the Arctic and Antarctic. The graph below shows average Antarctica surface temperatures from 1984-2014, compared to a base period 1950-1980.
The scientists note that over the last seven decades, the Antarctica sea ice area has “modestly expanded” and warming has been “nearly non-existent” over much of the ice sheet. NASA estimates current Antarctica ice loss at 147 gigatons a year, but with 26,500,000 gigatons still to go, this works out at annual loss of 0.0005%. At current NASA ice loss melt, it will all be gone in about 200,000 years, although the Earth may well have gone through another ice age, or two, before then.
Most alarmist commentary centres around the cyclical loss of sea ice around the coast and some warming on parts of the west of the continent. But sea ice cover is running at levels seen around 50 years ago, as the graph below shows. Small rises and falls in the early 2010s have been followed by a reversion to the mean.
The warmth to the west, seen in the first graph, could have been caused by any number of natural localised events including warmer oceanic waters and the effects of under-water volcanic activity. It has, of course, attracted widespread alarmist interest – in particular, the fate of the Thwaites ice stream, also known as the ‘Doomsday Glacier’. However, recently a group of oceanographers discovered that Florida-sized Thwaites had retreated at twice the rate in the past, when human-caused CO2 could not have been a factor. The retreat could have occurred centuries ago and is said to have been “exceptionally fast”.
Much of climate science today seems to suffer from confirmation bias. Few grants are available to those who don’t start with the premise that the climate is changing mostly, or entirely, due to humans burning fossil fuel. But many present, historic and paleo climate observations fail to establish a clear connection between temperatures and CO2 levels. In the past, the life-enhancing gas has occupied a space in the atmosphere up to 20 times higher, without evidence of huge temperature rises.
Singh and Polvani’s explanation for expected warming in Antarctica is the depth of the continent’s ice. To this end, they use two climate models that purport to show that the “high ice sheet orography” robustly decreases the climate sensitivity to extra CO2, and that “a flattened Antarctic ice sheet would experience significantly greater surface warming than the present-day Antarctica ice sheet”. This conclusion comes from computer models, but later in the paper is an admission that they fail to agree on significant matters. It is revealed that one of the models predicts less sea ice retreat in a flattened Antarctica when CO2 doubles, and the other one, more retreat.
In the science blog No Tricks Zone there has been an interesting debate on the lack of Antarctica warming. It was noted that NASA also tends to support the role of higher elevation of the ice as an explanation. For the rest of the world, states NASA, “the greenhouse effect still works as expected”. The average ice thickness in Antarctica is about 2,160 metres and compares with Greenland at around 1,600. The fact that Greenland has warmed of late might lead to the cynical observation that Antarctica has the wrong type of ice. One correspondent summarised the paper as the “lack of warming in spite of greenhouse gases is the wrong conclusion. The lack of warming is because of the increased greenhouse gases.” Another sighting, it would appear, of the old chestnut, “global cooling is caused by global warming”.
The science, as always, must be out. Attempting to connect every natural variation in weather and long-term climate to just one trace gas produced by humans leads to some unconvincing explanations, not least when climate models are involved.
Chris Morrison is the Daily Sceptic’s Environment Editor.
This article was originally published in the Daily Sceptic. It is republished here with permission.
