Climate Change Could Affect Global Timekeeping氣候變化或?qū)⒂绊懭蛴?jì)時(shí)

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.

一項(xiàng)研究稱，氣候變化正在影響地球的自轉(zhuǎn)速度，并可能影響人類的計(jì)時(shí)方式。這項(xiàng)發(fā)表在《自然》雜志上的研究指出，全球變暖已經(jīng)在影響全球計(jì)時(shí)。

“協(xié)調(diào)世界時(shí)”是根據(jù)地球自轉(zhuǎn)計(jì)算出來的，世界上大多數(shù)國家都用它來調(diào)節(jié)時(shí)鐘和時(shí)間。但地球的自轉(zhuǎn)速度并不是恒定的，因此會(huì)對我們的晝夜長短產(chǎn)生影響。地球液態(tài)的地核發(fā)生變化意味著地球的自轉(zhuǎn)速度略快。

為了糾正這一現(xiàn)象，自20世紀(jì)70年代以來，全球時(shí)鐘已經(jīng)增加了約27個(gè)閏秒。計(jì)時(shí)員計(jì)劃在2026年首次減少一秒，這被稱為“負(fù)閏秒”。然而，研究發(fā)現(xiàn)，氣候變化導(dǎo)致的冰雪融化在一定程度上抵消了這一加速。研究表明，現(xiàn)在冰原質(zhì)量損失的速度是30年前的5倍，這意味著可能直到2029年才需要負(fù)閏秒的變化。

“It’s kind of impressive， even to me. We’ve done something that measurably changes how fast the Earth rotates，” said Duncan Agnew， the author of the study. 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，” Mr Agnew added. “Many computer programs for leap seconds assume they are all positive， so these would have to be rewritten.”

There has been some skepticism of the study， however. Demetrios Matsakis， former chief scientist for time services at the US Naval Observatory， said， “Earth is too unpredictable to be sure if a negative leap second would be needed any time soon.”

這項(xiàng)研究報(bào)告的作者鄧肯·阿格紐說：“即使對我來說，這也是令人印象深刻的。我們已經(jīng)做了一些明顯改變地球自轉(zhuǎn)速度的事情。”負(fù)閏秒以前從未使用過，根據(jù)這項(xiàng)研究，負(fù)閏秒的使用將給全球的計(jì)算機(jī)系統(tǒng)“帶來前所未有的難題”。

阿格紐先生補(bǔ)充說：“這種情況以前從未發(fā)生過。許多計(jì)算機(jī)程序都默認(rèn)閏秒是正數(shù)，因此這些程序必將重寫。”

然而，也有一些人對這項(xiàng)研究持懷疑態(tài)度。美國海軍天文臺(tái)負(fù)責(zé)時(shí)間服務(wù)工作的前首席科學(xué)家德米特里奧斯·馬薩基斯說：“地球?qū)嵲谑请y以預(yù)測，因此在不久的將來是否需要負(fù)閏秒還無法確定。”