Arctic warming trends and their uncertainties based on surface temperature reconstruction under different sea ice extent scenarios

Abstract

IPCC AR6 states that the neglect of recent rapid warming in the Arctic generally leads to an underestimate of global warming trends. In this study, by reconstructing the surface temperature (ST) datasets in the Arctic under different sea ice extent scenarios (Imax and Imin), we respectively evaluated the annual and seasonal warming trends and their uncertainties from 1900 to 2020. The results show that the reconstructed datasets have a good representation of the ST change trends in the Arctic. In 1900–2020, the annual warming trends in the Arctic (0.17 ± 0.031 and 0.14 ± 0.025 °C per decade under the Imax and Imin reconstruction, respectively) are roughly 1.6–1.8 times the global mean warming trends (0.10 ± 0.008 and 0.09 ± 0.008 °C per decade). While in 1979–2020, the Arctic warming trends (0.66 ± 0.100 and 0.55 ± 0.080 °C per decade) increase to 3.1–3.5 times of the global warming trend (0.19 ± 0.023 and 0.18 ± 0.023 °C per decade) for Imax and Imin, respectively, indicating that the Arctic amplification effect has been significantly enhancing in recent decades. Although the seasonal warming trends are closely related to cloud feedback mechanisms, atmospheric circulation, and ocean circulation, they are not sensitive to the different reconstruction scenarios.