By JR on Saturday, March 18, 2017
Natural factors shown as a big influence on Arctic warming
The Arctic is the only place where there seems to have been some warming in recent times. So Warmists are constantly cheering it. But is the warming there part of anthropogenic global warming? Hard to see how when the globe overall is not warming. So what IS causing Arctic warming? The authors below have traced a lot of it to natural factors. The balance of the warming may be due to subsurface vulcanism. There are some huge undersea volcanoes in the Arctic, particularly along the Gakkel ridge
Influence of high-latitude atmospheric circulation changes on summertime Arctic sea ice
Qinghua Ding et al.
The Arctic has seen rapid sea-ice decline in the past three decades, whilst warming at about twice the global average rate. Yet the relationship between Arctic warming and sea-ice loss is not well understood. Here, we present evidence that trends in summertime atmospheric circulation may have contributed as much as 60% to the September sea-ice extent decline since 1979. A tendency towards a stronger anticyclonic circulation over Greenland and the Arctic Ocean with a barotropic structure in the troposphere increased the downwelling longwave radiation above the ice by warming and moistening the lower troposphere. Model experiments, with reanalysis data constraining atmospheric circulation, replicate the observed thermodynamic response and indicate that the near-surface changes are dominated by circulation changes rather than feedbacks from the changing sea-ice cover. Internal variability dominates the Arctic summer circulation trend and may be responsible for about 30–50% of the overall decline in September sea ice since 1979.
Nature Climate Change (2017) doi:10.1038/nclimate3241