The quandary of detecting the signature of climate change in Antarctica

The current global warming driven by human activities has been accentuated in Polar Regions due to the polar amplification, resulting in large releases of ice that have impacts on circulation and sea level at the global scale. In the Arctic, the temperature has increased at three times the global rate, and lead to significant melt of the Greenland ice sheet and sea ice decline. Yet, for Antarctica, the impact of warming is still poorly constrained given the lack of instrumental data and the large decadal climate variability. Using a compilation of 78 ice core records, we provide a high-resolution reconstruction of past temperatures over the last 1000 years for seven regions of Antarctica and direct evidence of Antarctic polar amplification at regional and continental scales. We also show that both the natural and forced variability are not captured by pseudo-proxy experiments using the CMIP5 and 6 ensembles. This that the feedback loops causing the polar amplification are not properly taken into account, leading to an underestimation of the magnitude of anthropogenic warming and its consequences in Antarctica.
The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)