Detection of anthropogenically driven trends in Arctic amplification.

The driving mechanism of Arctic amplification (AA) is so complex that no consistent and definitive conclusion has been formed yet. In particular, the internally and externally driven trends of AA have not been distinguished using observation-based methods. Given that the Arctic is more sensitive than other regions to anthropogenic greenhouse gas increases and other external forcings, we focus on separating anthropogenically driven trends from the Arctic surface air temperature (SAT) changes during 1979–2017 to quantify the contribution of anthropogenic effects on AA, with detection and attribution converted to probability distribution functions. Results indicate that the Arctic coast of the Siberian Great Plains, from the Barents Sea to the Kara Sea and eastward to the Bering Strait, has been warming most significantly, and is mainly dominated by anthropogenically driven trends. From 1979 to 2017, the minimum anthropogenically driven warming in most parts of the Arctic Ocean exceeds 2℃, especially the Kara Sea area, where the anthropogenically driven warming is significant, reaching 4℃. In addition, the minimum anthropogenic contributions exceed 60% in most parts of the Arctic Circle and are more than 80% of the warming trend in (75–90° N, 150–180° W). In 140° W–140° E Arctic region, the anthropogenically driven trend is the most remarkable, at 0.82℃ / decade, accounting for 84.5% of the measured warming trend. Meanwhile, the anthropogenically driven trend accelerates most rapidly in this area (0–140° W, 60–90° N). [ABSTRACT FROM AUTHOR]