Climate change is affecting the speed of the Earth’s rotation and could impact how we keep time, a study says. “Global warming is already affecting global timekeeping,” says the study, published in the journal Nature. Coordinated Universal Time (UTC) — which is used by most of the world to regulate clocks and time — is calculated by the Earth’s rotation. But the Earth’s rotation rate is not constant and can therefore have an effect on how long our days and nights are. Changes to the planet’s liquid core have meant the Earth has been spinning slightly quicker. Since the 1970s, to correct for this, about 27 leap seconds have been added to the global clock, with timekeepers planning on subtracting a second for the first time in 2026. This is known as a “negative leap second.” However, the study finds that ice melting caused by climate change has partly offset that acceleration. Ice sheets are now losing mass five times faster than they were 30 years ago, meaning that the negative leap second change will not be needed until 2029, the study suggests. “It’s kind of impressive, even to me, we’ve done something that measurably changes how fast the Earth rotates,” Duncan Agnew, the author of the study, told NBC News. “Things are happening that are unprecedented.” The negative leap second has never been used before and, according to the study, its use “will pose an unprecedented problem” for computer systems across the world. “This has never happened before, and poses a major challenge to making sure that all parts of the global timing infrastructure show the same time,” Mr. Agnew, who is a researcher at the University of California, San Diego told AFP news agency. “Many computer programs for leap seconds assume they are all positive, so these would have to be rewritten,” he added. There has been some skepticism of the study, however. Demetrios Matsakis, former chief scientist for time services at the US Naval Observatory, told AFP that “Earth is too unpredictable to be sure” if a negative leap second would be needed any time soon. Human activities like burning fossil fuels are causing world temperatures to rise. That temperature rise is having a huge effect on the environment, including the rapid melting of glaciers and ice sheets.(chinadaily.com) Words to Learn 相關詞匯 【協調世界時】 xiétiáo shìjièshí Coordinated Universal Time (UTC) UTC is the basis for civil time today. This 24-hour time standard is kept using highly precise atomic clocks combined with the Earth’s rotation. 【閏秒】 rùnmiǎo leap second a second added to UTC in order to keep it synchronized with astronomical time 一項研究稱，氣候變化正在影響地球的自轉速度，并可能影響人類的計時方式。 這項發表在《自然》（Nature）雜志上的研究指出：“全球變暖已經在影響全球計時?！?/p> “協調世界時”（UTC）是根據地球自轉計算出來的，世界上大多數國家都用它來管理時鐘和時間。 但地球的自轉速度并不是恒定的，因此會對我們的晝夜長短產生影響。 地球液態內核的變化意味著地球自轉速度略快。 自 20 世紀 70 年代以來，為了糾正這一現象，全球時鐘已經增加了約 27 個閏秒，計時員計劃將在 2026 年首次減少一秒。這被稱為 “負閏秒”。 然而，研究發現，氣候變化導致的冰雪融化部分抵消了這一加速。 研究表明，冰蓋現在的質量損失速度是30年前的5倍，這意味著可能直到2029年才需要負閏秒的變化。 這項研究的作者鄧肯?阿格紐告訴美國全國廣播公司新聞（NBC News）：“即使對我來說，我們已經做了一些可以適度地改變地球旋轉速度的事情，這也是令人印象深刻的?！?/p> “正在發生的事情是前所未有的。” 負閏秒以前從未使用過，根據這項研究，負閏秒的使用將給全球計算機系統 “帶來前所未有的問題”。 加州大學圣迭戈分校的研究員阿格紐先生告訴法新社記者：”這種情況以前從未發生過，這對確保全球計時基礎設施的所有部分都顯示相同的時間構成了重大挑戰。” 他補充說：“許多計算閏秒的計算機程序都假定它們都是正數，因此這些程序必須重寫?！?/p> 然而，也有一些人對這項研究持懷疑態度。 美國海軍天文臺負責時間服務的前首席科學家德米特里奧斯?馬薩基斯告訴法新社說，“地球太不可預測了，無法確定是否在不久的將來就需要負閏秒。” 燃燒化石燃料等人類活動正在導致全球氣溫上升。 氣溫上升對環境產生了巨大影響，包括冰川和冰蓋的迅速融化。 (chinadaily.com) | 