Global warming, driven by climate change, poses a significant threat to life on Earth. Surprisingly, it is already influencing global timekeeping, according to a recent study.
Published in Nature, the research reveals that the accelerated melting of ice in Greenland and Antarctica has altered Earth’s angular velocity more rapidly than previously observed. Since 1972, the angular velocity of Earth’s liquid core has been steadily decreasing, leading to an increase in the angular velocity of the rest of the planet.
By extrapolating these trends, scientists predict that the current definition of Coordinated Universal Time (UTC) will require a negative discontinuity by 2029. This poses a unique challenge for computer network timing and may necessitate adjustments to UTC earlier than planned.
Interestingly, before 1955, high-quality timescales relied on synchronization with Earth’s rotation, which was considered more consistent than any available oscillator. The second was defined as a specific fraction of Earth’s rotational period relative to the stars, creating a timescale known as UT.
However, the introduction of atomic frequency standards using caesium proved far more stable than Earth’s rotation. Consequently, the second was redefined based on atomic frequency, leading to the establishment of an atomic timescale called TAI in 1955. Although UT and TAI were aligned in 1958, they have since diverged due to Earth’s variable rotation rate. This historical variability continues to challenge UTC and is expected to pose even greater difficulties in the future.
