Recent regional climate cooling on the Antarctic Peninsula and associated impacts on the cryosphere

Abstract

The Antarctic Peninsula (AP) is often described as a region with one of the largest warming trends on Earth since the 1950s, based on the temperature trend of 0.54°C/decade during 1951-2011 recorded at Faraday/Vernadsky station. Accordingly, most works describing the evolution of the natural systems in the AP region cite this extreme trend as the underlying cause of their observed changes. However, a recent analysis (Turner et al., 2016) has shown that the regionally stacked temperature record for the last three decades has shifted from a warming trend of 0.32°C/decade during 1979-1997 to a cooling trend of -0.47°C/decade during 1999-2014. While that study focuses on the period 1979-2014, averaging the data over the entire AP region, we here update and re-assess the spatially-distributed temperature trends and inter-decadal variability from 1950 to 2015, using data from ten stations distributed across the AP region. We show that Faraday/Vernadsky warming trend is an extreme case, circa twice those of the long-term records from other parts of the northern AP. Our results also indicate that the cooling initiated in 1998/1999 has been most significant in the N and NE of the AP and the South Shetland Islands (>0.5°C between the two last decades), modest in the Orkney Islands, and absent in the SW of the AP. This recent cooling has already impacted the cryosphere in the northern AP, including slow-down of glacier recession, a shift to surface mass gains of the peripheral glacier and a thinning of the active layer of permafrost in northern AP islands.

Changes in glacier dynamics in the northern Antarctic Peninsula since 1985

“…Thus, the higher retreat rates in sector East after 1995 could be indirectly caused by the disintegration of Prince Gustav and Larsen A Ice Shelf in Sector East-IceShelf. At Base Marambio, ∼ 100 km east of this sector, approximately 2 • C higher mean annual air temperatures were recorded in the period 1996-2005 as compared to the period 1986-1995 (Oliva et al, 2017). Unfortunately, no tempera- The symbols used for the velocity change categories (see Table 3) are the same as in Fig.…”

“…This process can be initiated by climatic forcing (Benn and Evans, 1998). Significant higher surface air temperature at the northeastern AP and a cooling trend in the 21st century was reported by Oliva et al (2017) and Turner et al (2016) (see Sect. 1).…”

“…1) and the observed retreat of tidewater glaciers on James Ross Island in the period 1975(Skvarca et al, 1995. However, a recent cooling trend on the AP was revealed by Oliva et al (2017) and Turner et al (2016) since the late 1990s. Shepherd et al (2012) compiled a comprehensive glacier mass balance database of the polar ice sheets.…”

“…1). Hence, we assume that the initial recessions of the glaciers in sector East were forced by the warming observed by Oliva et al (2017) and Skvarca et al (1998) since the 1970s. Therefore, this initial frontal destabilization and retreat led to high flow speeds at the beginning of our ice dynamics time series (earliest velocity measurements from 1992) and the subsequently observed frontal stabilization (after 1985) caused the deceleration of the ice flow.…”

Recent Deceleration of the Ice Elevation Change of Ecology Glacier (King George Island, Antarctica)

“…This led to a large scale retreat of glacial fronts an rapid glacial change, including the disintegration of the Larsen A and B ice shelves [16,17]. However, it was shown by Turner et al [18], Oliva et al [19] that since 1999 a regional cooling has been observed, which has also influenced the behaviour of the cryosphere [19,20]. Air temperature records from the Bellingshausen Station (Figure 1; [21]) confirmed that for the 2012-2015 period a significant cooling was observed during summer months on the Fildes Peninsula, King George Island.…”