Jul 20, 2016

Absence of 21st century warming on Antarctic Peninsula consistent with natural variability

John Turner, Hua Lu, Ian White, John C. King, Tony Phillips, J. Scott Hosking, Thomas J. Bracegirdle, Gareth J. Marshall, Robert Mulvaney, Pranab Deb
  • States that, since the 1950s, research stations on the Antarctic Peninsula have recorded some of the largest increases in near-surface air temperature in the Southern Hemisphere
  • States that this warming has contributed to the regional retreat of glaciers, disintegration of floating ice shelves and a ‘greening’ through the expansion in range of various flora 
  • States that several interlinked processes have been suggested as contributing to the warming, including stratospheric ozone depletion, local sea-ice loss, an increase in westerly winds, and changes in the strength and location of low–high-latitude atmospheric teleconnections
  • Uses a stacked temperature record to show an absence of regional warming since the late 1990s
  • Finds the annual mean temperature has decreased at a statistically significant rate, with the most rapid cooling during the Austral summer
  • Finds that 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
  • Finds these circulation changes have also increased the advection of sea ice towards the east coast of the peninsula, amplifying their effects
  • Notes that these findings cover only 1% of the Antarctic continent and emphasize that decadal temperature changes in this region are not primarily associated with the drivers of global temperature change but, rather, reflect the extreme natural internal variability of the regional atmospheric circulation