氣候變化是指天越來越長, 科學家發現

Climate change means days are getting longer, scientists find

 

技術Guardian.co.uk這篇文章題為 “氣候變化是指天越來越長, 科學家發現” was written by Oliver Milman, for theguardian.com on Friday 11th December 2015 19.00 世界標準時間

The impact of climate change may appear to be overwhelmingly negative but there is a bright spot for those who struggle to find enough time in the day: 冰川融化是造成地球自轉減慢,從而延長我們的日子, 新的研究發現,.

哈佛大學的研究人員提供了一個答案,一個長期持有的難題在如何冰川融化的影響地球的旋轉和軸向, 計算那一天的持續時間已經過去的加長了一毫秒 100 歲月.

The brakes will be more sharply applied to the Earth’s rotation as glaciers melt at an ever faster rate, meaning that at least five milliseconds will be added to each day over the course of the 21st century. The axis of the Earth will shift too, with the north pole set to move position by about 1cm (o.4in) during this century.

這個調查, published in Science Advances, apparently solved a scientific puzzle known as “Munk’s enigma”, which came from a 2002 researcher paper by oceanographer Walter Munk, 研究如何冰川的融化已經改變了地球的自轉和軸.

由於陸冰從兩極融化,由於上升的大氣溫度, 在世界各地水換檔重量應引起的變化對於軸線在其上地球旋轉, 並在旋轉稍微擺動. 還, 朝赤道水增加的重量會導致地球放緩, 很多的方式,如果他或她達到了自己的手臂遠離自己的身體旋轉的花樣滑冰運動員將放緩.

Munk factored in the impact of the end of the Ice Age 5,000 幾年前, when melting over the previous 15,000 years would have helped slow the Earth’s rotation. 但, surprisingly, he found that even with average sea level rises of 2mm a year during the 20th century, there was no change to the Earth’s rotation or axis beyond that caused by the Ice Age ending.

“There should’ve been a whopping great signal and it would be immediate as it only takes days or weeks for that melted water from the poles to shift around the world,” said Jerry Mitrovica, 地球物理學教授研究的哈佛大學和領導者.

米特羅維察的球隊又回到了蒙克的研究和應用的最新科學認識到它. 他們發現,芒克略有高估的平均海平面上升 - 每年在20世紀,它是在1mm左右至1.5mm而小於2mm.

他們還採用了更新的模式來計算. 芒克認為,地球已迅速調整到作為冰河時代結束時發生冰融化. 最近認識的這個時候, 然而, suggests that the Earth was not as spherical as it is now for a long time, as the huge ice sheets caused the poles to flatten and the equator to bulge out.

Once the team had factored in other influences such as the tides, they found that the glacier melting of the 20th century had indeed caused the Earth to slow and wobble. The speed of the planet’s rotation can be gauged from measurements of stars’ position in relation to Earth and also the orbit of satellites, 其中有調整略如果世界上的旋轉變化.

這種放緩將成為更加明顯. 全球平均海平面上升已經結束3毫米, 根據IPCC, 與世界冰川的卷集之間低迷所 15% 和 85% 由 2100, 這取決於國家如何大幅減少溫室氣體排放和反大規模砍伐森林.

最近的一項研究發現,世界上冰川的退縮電流 是“史無前例”, 科學家警告說,巨大的冰川 格陵蘭 that holds enough water to raise global sea levels by half a meter has begun to crumble into the North Atlantic Ocean. Sea level rise is also fuelled by thermal expansion, where the ocean grows as it warms up.

“The period of a day is now a millisecond longer than a century ago but that will accelerate as the melting increases,” Mitrovica said. “People won’t be running from their houses screaming about an extra millisecond but it adds yet further confirmation of what we are doing to our environment. 這是另一種指紋。“

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