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 相关词汇

【协调世界时】 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.

【闰秒】 rùnmiǎo leap second

a second added to UTC in order to keep it synchronized with astronomical time

一项研究称，气候变化正在影响地球的自转速度，并可能影响人类的计时方式。

这项发表在《自然》（Nature）杂志上的研究指出：“全球变暖已经在影响全球计时。”

“协调世界时”（UTC）是根据地球自转计算出来的，世界上大多数国家都用它来管理时钟和时间。

但地球的自转速度并不是恒定的，因此会对我们的昼夜长短产生影响。

地球液态内核的变化意味着地球自转速度略快。

自 20 世纪 70 年代以来，为了纠正这一现象，全球时钟已经增加了约 27 个闰秒，计时员计划将在 2026 年首次减少一秒。这被称为 “负闰秒”。

然而，研究发现，气候变化导致的冰雪融化部分抵消了这一加速。

研究表明，冰盖现在的质量损失速度是30年前的5倍，这意味着可能直到2029年才需要负闰秒的变化。

这项研究的作者邓肯•阿格纽告诉美国全国广播公司新闻（NBC News）：“即使对我来说，我们已经做了一些可以适度地改变地球旋转速度的事情，这也是令人印象深刻的。”

“正在发生的事情是前所未有的。”

负闰秒以前从未使用过，根据这项研究，负闰秒的使用将给全球计算机系统 “带来前所未有的问题”。

加州大学圣迭戈分校的研究员阿格纽先生告诉法新社记者：”这种情况以前从未发生过，这对确保全球计时基础设施的所有部分都显示相同的时间构成了重大挑战。”

他补充说：“许多计算闰秒的计算机程序都假定它们都是正数，因此这些程序必须重写。”

然而，也有一些人对这项研究持怀疑态度。

美国海军天文台负责时间服务的前首席科学家德米特里奥斯•马萨基斯告诉法新社说，“地球太不可预测了，无法确定是否在不久的将来就需要负闰秒。”

燃烧化石燃料等人类活动正在导致全球气温上升。

气温上升对环境产生了巨大影响，包括冰川和冰盖的迅速融化。

(chinadaily.com)