Interest in ‘global warming’ is waning, because global cooling continues to occur

The Antarctic Peninsula (western shore of Antarctica) is a triangular, mountainous land with a coastline of dramatic, calving glaciers and rich wildlife, and it exemplifies the popular image of Antarctica––although this regions covers only 1% of the entire Antarctic continent. The continent comprises more than 90% of ice on the planet. Over the past half century, it has been touted as one of the most rapidly warming regions on Earth. This warming is associated with major ‘physical and biologi­cal changes’, including a decline in the Adélie penguin population and disintegration in 2002 of a large portion of the Larsen B ice shelf––a major geographical feature that had existed for millennia.

It has been accepted by many that the changes at this northernmost point in Ant­arctica is “part of the inexorable southward march of purported ‘anthropogenic climate change”. Thus, it is quite remarkable (especially for a journal such as Nature) to see a paper published in Nature [attached] reporting that the Antarctic Peninsula has actually cooled during the past two decades. Authors show conclusively that the average tem­perature on the peninsula has decreased by about 0.5 °C per decade since the late 1990s––which is about the same rate at which it warmed in the preceding five decades. These fluctuations are therefore within normal variability of temperatures of any region on Earth.

To understand this apparent reversal, one has to recognize that the average warming trend observed since the middle of the twentieth century reflects several aspects of Antarctic Peninsula climate. Which aspect might dominate … appears to vary by both location and season. For example, the oft-heard claim that the peninsula is the fastest-warming place on Earth is accurate only during the winter, as recorded at the Faraday/Vernadsky station on the west coast. The annual mean temperature has decreased at a statistically significant rate, with the most rapid cooling during the Austral summer. Temperatures have decreased as a consequence of a greater frequency of cold, east-to-southeasterly winds, resulting from more cyclonic conditions in the northern Weddell Sea associated with a strengthening mid-latitude jet. The fact that solar activity has continued to decrease during these past two decades might be another contributing factor.

Winter warming at this western Antarctic sta­tion––more than 6 °C since records began in 1947––had been associated with a rapid decrease in sea ice. It should be emphasized that these studies cover only 1% of the entire Antarctic continent and emphasize that decadal temperature changes in this region simply reflect the extreme natural internal variability of regional atmospheric circulations.

Nature  21 July 2o16; 535: 411–415  &  pp 358-359 (News’n’Views)

This entry was posted in Center for Environmental Genetics. Bookmark the permalink.