The rate of Arctic surface warming has reached 2 to 4 times the global average – a phenomenon known as ‘Arctic amplification’. Traditional theories suggest that snow and ice melt reduce surface albedo, leading to greater absorption of solar radiation and forming a positive ‘ice-albedo feedback’ loop. However, a research team led by Professor Chuanfeng Zhao from Peking University has uncovered a key regulatory role played by clouds in this process, based on CERES satellite data from 2000 to 2020 and simulations from the CMIP6 climate models.
The study found that even when cloud properties remain unchanged, the melting of snow and ice can trigger an enhancement in the cloud short-wave cooling effect. Detailing on the study, Annan Chen, a PhD candidate at Peking University, said, “This, in turn, partially slows down further melting of snow and ice, offering a new perspective on the self-regulating mechanisms of the climate system.”
Based on satellite observations from 2000 to 2020 and CMIP6 climate model data, the analysis shows that Arctic snow and ice coverage decreased by 0.016 per decade. This triggered an increase in the cloud short-wave radiative cooling effect, leading to radiative cooling at the top of the atmosphere and surface reaching -1.25 ± 0.49 and -0.21 ± 0.20 W/m² per decade, respectively. As a result, the average annual sea ice melting rate got slowed by 3.45 cm, with localized reductions up to 10 cm per year. For more information: https://bit.ly/3Gj7psb.
