Resumen de Impacts on the cryosphere of the recent cooling recorded in the Antarctic Peninsula region

Marc Oliva, Francisco José Navarro Valero , Filip Hrbáček, Armand Hernández, Daniel Nývlt, Paulo Pereira, Jesús Ruiz Fernández, Ricardo Trigo

• The majority of the papers and international reports (e.g. IPCC, 2013) published during the early 21st century have described the Antarctic Peninsula (AP) as one of the fastest warming regions on Earth since the mid-20th century. In this study, we present a reassessment of the decadal climate variability from 1950 until 2015 using data from ten stations distributed across the AP region. Results suggest a significant cooling since 1998–2000 within the long-term warming trend. Mean annual air temperatures (MAAT) were still negative in all sites, oscillating between -1.8 and -8.3 ºC for the 1986–2015 period. The coldest decade was 1956–1965 in the southern AP region and 1966–1975 in the northern part.

  The warmest decade was 1996–2005 mainly driven by the powerful effects of El Niño of 1997–1998. Since then, temperatures have dropped across the region, with MAATs significantly lower than the previous decade average in the N-NE of the AP (0.6–0.9 ºC), South Shetland Islands (0.5–0.6 ºC), Orkney Islands (0.2 ºC), but still slightly higher in the SW corner of the AP (0.1–0.2 ºC). This decrease was mainly compelled by lower autumn and winter temperatures, which control the presence of sea ice, and in turn, influence temperatures inland. The consequences of this significant cooling trend have impacted the cryosphere in the region: increase of extent and duration of sea ice, positive glacial annual mass-balances and thinning of the active layer of permafrost.