Ten days ago the journal Science issued an embargoed press release about a forthcoming paper that suggested the warming observed in West Antarctica was due to natural climatic variability. West Antarctica has always been looked on by alarmists as being the southern example of polar temperature amplification – a phenomenon predicted by most climate change models. The Arctic temperature amplification is very apparent so there must be an Antarctic equivalent, and there it is.
But while scientists have been well aware that Antarctica is warming asymmetrically, with West Antarctica experiencing more than East Antarctica and frequently attributed to climate change, the underlying causes of this phenomenon have been poorly understood, and the suggestion that West Antarctica may be experiencing natural warming has been suggested before though not taken up very enthusiastically, if at all.
This new paper, “The internal origin of the west-east asymmetry of Antarctic climate change”, expresses the dilemma well. In explaining the asymmetry, it suggests factors such as atmosphere-ocean feedbacks along the coast of West Antarctica and the shape of the Antarctic terrain combine to create a pattern of upper troposphere circulation over the West Antarctic subcontinent that flows opposite to the Earth’s rotation. The researchers conclude,”the current west-east asymmetry of Antarctic surface climate change is undoubtedly of natural origin because no external factors (e.g., orbital or anthropogenic factors) contribute to the asymmetric mode.”
They add that the consistent pattern of warmer sea surface temperatures over the Amundsen and Bellingshausen Antarctic seas suggests that regional sea surface temperature anomalies around Antarctica are a driving factor behind the continent’s asymmetrical warming. Paleoclimate datasets revealed variability in surface air temperatures spanning multiple decades, suggesting climate fluctuations in the tropics, such as the El Niño Southern Oscillation, may also contribute to the discrepancies in warming rates between both subcontinents.
Overall, it’s a fascinating paper especially given the concern about the region’s ice decline leading to present and future sea level change. But unless you look at two or three specialised outlets you won’t have heard about it.
via climate science
June 21, 2020 at 01:30AM