By Ethan Linck
22 July 2016
(The Stranger) – One Small Part of Antarctica Stayed Cool While the Rest Warmed: Perhaps the most frustrating aspect of climate change denialism is the willful idiocy of using local exceptions to a widely supported trend as evidence that trend is false. Climate science—like meteorology, biology, and political science—is a field defined by intrinsic variation of its object of study, and is reliant on statistical tools with the power to infer signal from noise. The inherent uncertainty of this pursuit can lead some researchers (like UW’s Cliff Mass) to avoid attributing any single weather event to climate change, even if the event itself is consistent with predictions of weather under future climate regimes, for fear of discrediting climate research more broadly. (It will not surprise regular Puget Sound news readers to learn this is not a universally supported position. Which is why a recent Nature study highlighting one such local exception—the absence of 21st century warming on the Antarctic Peninsula in the face of overall increasing temperatures elsewhere across the continent—is both good, necessary science, but at the same time it's sure to be seized upon from predictable quarters, the deniers of a widely supported trend, global warming. [more]
ABSTRACT: Since the 1950s, research stations on the Antarctic Peninsula have recorded some of the largest increases in near-surface air temperature in the Southern Hemisphere1. This warming has contributed to the regional retreat of glaciers2, disintegration of floating ice shelves3 and a ‘greening’ through the expansion in range of various flora4. Several interlinked processes have been suggested as contributing to the warming, including stratospheric ozone depletion5, local sea-ice loss6, an increase in westerly winds5, 7, and changes in the strength and location of low–high-latitude atmospheric teleconnections8, 9. Here we use a stacked temperature record to show an absence of regional warming since the late 1990s. 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. These circulation changes have also increased the advection of sea ice towards the east coast of the peninsula, amplifying their effects. Our 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.