Wildly unexpected consequences of polar ice melt has scientists on edge

Have you felt like the days are getting longer? If so, your perception is spot on. This unexpected occurrence is closely tied to the manner in which polar ice and water are shifting around our planet, and dramatically impacting the Earth’s rotation and spin axis.

A couple of recent NASA-funded studies have discovered that the length of Earth’s days is indeed on an upward tick.

What’s more, the pace is picking up. These studies underscore the profound influence of climate change on our planet’s fundamental dynamics.

Masterminds behind the curtain

The central character behind the scenes of these fascinating findings is Dr. Surendra Adhikari, a distinguished geophysicist stationed at NASA’s Jet Propulsion Laboratory (JPL) in Southern California.

The research conducted by his team aims to demonstrate how Earth’s surface changes, driven by climatic events, are influencing our planet’s rotation.

These changes, whether natural phenomena or human-induced activities like urbanization and industrialization, significantly impact Earth’s rotational dynamics.

This could potentially affect everything from weather patterns to the length of our days.

By exploring these dynamics, we can better understand the intricate connections between our environment and planetary behavior, highlighting the broader implications of such transformations.

Polar ice melt and Earth’s spin

How does this work, you ask?

When ice sheets and glaciers disappear quicker than they can replenish, and when underground water reservoirs (or aquifers) are depleted faster than the rainfall can restock them, this leads to a jumbled mass on Earth.

As these vast quantities of water shift from frozen stores and underground reservoirs into the oceans, they cause the distribution of the Earth’s mass to change.

This redistribution of weight causes the planet to wobble on its axis as it spins, akin to how an off-balance top might spin unevenly.

The wobbling effect makes the planet’s rotation sluggish, which, in turn, lengthens our days by minuscule amounts over time.

This phenomenon, known as polar wander, has been under observation by scientists since the dawn of the 20th century, and its implications continue to be a critical area of research in understanding Earth’s changing climate and its broader impacts.

Earth’s changing rotation and day length

In their first study, the scientists scrutinized the polar motion over a span of 120 years, and came to the conclusion that the Earth’s axis movements could heavily be attributed to shifts in groundwater, ice sheets, glaciers, and sea levels.

The bulk of these mass variations during the 20th century were mainly due to natural climate cycles, as noted in their publication in Nature Geoscience.

The scientists then turned their focus onto day length in a follow-up study published in Proceedings of the National Academy of Sciences.

Their astonishing discovery revealed that since the turn of the millennium, days have been lengthening at a rate of about 1.33 milliseconds per century which is faster than any time in the past one hundred years.

This acceleration is primarily due to the amplified melting of glaciers and the ice sheets in Antarctica and Greenland, a direct result of human-induced greenhouse gas emissions.

“The common thread between the two papers is that climate-related changes on Earth’s surface, whether human-caused or not, are strong drivers of the changes we’re seeing in the planet’s rotation,” explained Adhikari.

Evolution of polar ice motion tracking

In the early days, scientists gauged polar motion by deducing the apparent movements of stars, observing their positions and tracking changes to understand the Earth’s shifting axis. Over time, as technology advanced, more sophisticated techniques were adopted.

One such method is very long baseline interferometry, which deciphers radio signals from distant quasars to measure the Earth’s orientation with high precision.

Another technique is satellite laser ranging, which involves shooting lasers at satellites equipped with retroreflectors to determine their exact positions in orbit and, consequently, infer details about the Earth’s movement.

These advancements have significantly improved our understanding of polar motion and its implications for global navigation and geophysics.

Power of machine learning

Machine-learning algorithms were employed to meticulously dissect 120 years of data, ranging from 1900 to 2018.

This comprehensive analysis revealed that an impressive 90% of the recurring fluctuations during this period could be explained by shifts in groundwater, ice sheets, glaciers, and sea levels.

These findings indicate that changes in our planet’s water systems play a significant role in these variations.

The balance of the fluctuations, accounting for the remaining 10%, were largely attributed to Earth’s internal dynamics, such as tectonic activities and volcanic processes, which also contribute to the planet’s complex and ever-changing nature.

Human influence behind polar motion

Past investigations have established a connection between recent polar motion and human activities, underscoring the profound impact of our actions on the Earth’s axis.

For instance, Dr. Adhikari’s earlier work attributed a sudden eastward drift of the axis around 2000 to the quicker melting of the Greenland and Antarctic ice sheets, which significantly altered the distribution of mass on the planet.

Additionally, groundwater depletion in Eurasia has been identified as a critical factor, further contributing to this shift in the Earth’s rotational axis.

“It’s true to a certain degree” that human activities factor into polar motion, said Mostafa Kiani Shahvandi, lead author of both papers and a doctoral student at the Swiss university ETH Zurich.

“But there are natural modes in the climate system that have the main effect on polar motion oscillations.”

Crux of satellite data

Researchers capitalized on satellite observations from the GRACE mission and its follow-on GRACE-FO, together with earlier mass-balance studies, to gain a comprehensive understanding of how changes in groundwater, ice sheets, and glaciers contributed to rising sea levels in the 20th century.

These detailed observations allowed scientists to track the movement and distribution of water on Earth with unprecedented accuracy, shedding light on the complex interactions between various components of the Earth’s hydrological system.

This research is crucial for predicting future sea level rise and its potential impact on coastal communities worldwide.

Impact of human behavior on polar ice

In summary, these findings highlight the intricate and far-reaching consequences of human-induced climate change and resource exploitation on our planet’s orbital stability.

Dr. Adhikari’s profound statement rings true, “In barely 100 years, human beings have altered the climate system to such a degree that we’re seeing the impact on the very way the planet spins.”

The far reaching impacts of climate change serve as a stark reminder of the urgency and sustained efforts required to reduce emissions, and mitigate the effects of climate change, thus guaranteeing a stable future for our planet and all its inhabitants.

As we continue to understand these complex connections between our actions and Earth’s natural processes, we can better appreciate the importance of nurturing our planet.

Let’s pledge to adopt informed decisions and collaborate to safeguard our planet for the sake of future generations.

The full study was published in the journals Nature Geoscience and  Proceedings of the National Academy of Sciences.

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