Research press release


Nature Climate Change

Climate change: The South Pole feels the heat

1989年以降の南極点における温暖化のペースが、全球平均の3倍以上になっていることを報告する論文が、Nature Climate Change に掲載される。この温暖化期の主な駆動要因は、熱帯における自然な気候変化であり、温室効果ガスの増加によって温暖化が激化した可能性が高いとされる。


今回、Kyle Clemたちの研究チームは、測候所の観測データ、グリッド観測気候モデルを分析して、南極点における温暖化傾向を調べた。その結果、過去30年間の南極内陸部における大幅な温暖化の主な駆動要因が熱帯地方にあることが明らかになった。つまり、熱帯太平洋西部の海洋温度が上昇しており、そのためにウェッデル海(南大西洋高緯度海域)の上空の大気圧が低下し、南極点への暖気の輸送が増えたのだ。Clemたちは、このような南極の海岸線に沿った大気の変化が、南極の内陸部での数十年規模の気候異常を駆動する重要な機構だと考えている。


The South Pole has warmed at over three times the global rate since 1989, according to a paper published in Nature Climate Change. This warming period was mainly driven by natural tropical climate variability and was likely intensified by increases in greenhouse gas, the study suggests.

The Antarctic climate exhibits some of the largest regional temperature trends on the planet. Most of West Antarctica and the Antarctic Peninsula experienced warming and ice-sheet thinning during the late twentieth century, and this has continued to the present day. By contrast, the South Pole — located in the remote and high-altitude continental interior — cooled until the 1980s and has since warmed substantially. These trends are affected by natural and anthropogenic climate change, but the individual contribution of each factor is not well understood.

Kyle Clem and colleagues analysed weather station data, gridded observations and climate models to examine warming trend at the South Pole, and found that it was chiefly driven by the tropics. Warm temperatures in the western tropical Pacific Ocean — associated with the negative phase of the Interdecadal Pacific Oscillation — increased the delivery of warm air to the South Pole. Stronger winds around Antarctica — caused by a shift to a positive phase of the Southern Annular Mode — further boosted this warming. The authors suggest these atmospheric changes along Antarctica’s coast are an important mechanism driving climate anomalies in its interior.

The authors argue that these warming trends were unlikely the result of natural climate change alone, emphasizing the effects of anthropogenic warming and large tropical climate variability on Antarctic climate.

doi: 10.1038/s41558-020-0815-z


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