Earth’s Days to Grow at an Unprecedented Rate as Polar Ice Melts

Scientists are uncovering more ways our planet is being affected as the climate crisis escalates. A recent study published in the Proceedings of the National Academy of Sciences has revealed that the melting of polar ice caps is causing Earth to spin more slowly, leading to longer days at an unprecedented rate.

Impact of Melting Polar Ice

The study, co-authored by Surendra Adhikari from NASA’s Jet Propulsion Laboratory and Benedikt Soja from ETH Zurich, explains that the melting polar ice from Greenland and Antarctica is redistributing mass to the equator. This redistribution of water acts similarly to a figure skater extending their arms during a spin, causing them to slow down. As the ice melts, the additional water around the equator increases Earth’s physical inertia, slowing its rotation.

Earth’s Changing Shape

Though we often think of Earth as a perfect sphere, it is an “oblate spheroid,” meaning it bulges at the equator. This shape constantly changes due to various factors, such as daily tides, tectonic plate movements, and natural disasters like earthquakes, polar ice and volcanic eruptions. These changes impact the planet’s rotation and, consequently, the length of our days.

Measuring Earth’s Rotation

Scientists used observational techniques like Very Long Baseline Interferometry (VLBI) and the Global Positioning System (GPS) to understand these changes. VLBI measures the time it takes for radio signals from space to reach different points on Earth, allowing scientists to infer variations in the planet’s orientation and the length of the day. GPS technology measures Earth’s rotation to within one-hundredth of a millisecond, and ancient eclipse records dating back millennia were also utilized.

Implications for Space Travel

A slower Earth rotation means longer days by a few milliseconds. While this might seem negligible, it has significant implications for space travel and navigation. Accurate knowledge of Earth’s orientation is critical for communicating with spacecraft, such as the Voyager probes, now beyond our Solar System. A slight deviation in calculations can lead to significant errors over vast distances.

Climate Change vs. Lunar Influence

Currently, the Moon’s gravitational pull, through tidal friction, is the most significant factor slowing Earth’s rotation, causing a deceleration of 2.40 milliseconds per century over millions of years. However, the study suggests that if greenhouse gas emissions continue at their current rate, the warming climate will substantially impact Earth’s rotation by the end of the 21st century than the Moon’s pull.

Future Projections

From 1900 to today, climate change has caused days to lengthen by approximately 0.8 milliseconds. Under a worst-case scenario with high greenhouse gas emissions, climate change could extend days by 2.2 milliseconds by the year 2100. While these changes are too small for humans to perceive directly, they could have far-reaching effects on navigation and communication technologies.

Conclusion

The findings from this study highlight yet another profound impact of climate change on our planet. As polar ice melts, mass redistribution will keep altering Earth’s rotation, leading to longer days. This underscores the urgency of addressing climate change to mitigate its multifaceted consequences.