How robust are the temperature trends on the Antarctic Peninsula?

Abstract

The upward evolution of temperatures in the Antarctic Peninsula has weakened and even reversed in the last two decades. Due to the long-term variability of the region it is not easy to assess whether observed recent cooling trends are consistent with the internal variability or not. For this reason, in this paper we assess the robustness of the trends by analyzing their sensitivity with respect to the choice of time period selected. Every possible temperature trend in the 1958-2016 interval has been calculated and displayed in a two-dimensional parameter diagram. Our results suggest that the warming observed in the Antarctic Peninsula since 1958 is robust, as all periods longer than 30 years exhibit statistically significant changes, especially in summer (with lower magnitude and higher significance) and autumn and winter (whit larger magnitude and lower significance). Instead, periods shorter than 30 years exhibit alternations of warming and cooling periods, and therefore do not represent robust trends even if they are statistically significant. Consequently, the recent 20-year cooling trend cannot be considered at the moment as an evidence of a shift in the overall sign of the trend.