Global warming has been discovered to have a surprising effect on our everyday lives: it's slowing down the
Earth's rotation, and this could mess with how we keep time. A recent study, hot off the presses on Wednesday,
points to the culprit: melting polar ice, a direct result of human-caused climate change.
Think of it like this: when the ice at the poles melts, it changes where Earth's mass is concentrated. Picture a
figure skater spinning on ice. If she extends her arms or legs, she slows down. But tuck those arms in, and she
spins faster. That's kind of what's happening to our planet.
Duncan Agnew, a smarty-pants geophysicist from the University of California San Diego, explains it simply. As the
ice melts, all that water heads towards the equator, making Earth heavier around its middle.
“What you’re doing with the ice melt is you’re taking water that’s frozen solid in places like Antarctica and
Greenland, and that frozen water is melting, and you move the fluids to other places on the planet,” said Thomas
Herring, a professor of geophysics at the Massachusetts Institute of Technology, “The water flows off towards the
equator.”
Human influence has changed the speed of the Earth's rotation measurably. “Things are happening that are
unprecedented,” Agnew said.
His study suggests that the Earth has begun to spin faster in recent decades because of a combination of factors.
This temporary trend has prompted scientists to consider subtracting a single “negative leap second” from clocks
worldwide as soon as 2026 for the first time. However, the melting of polar ice has delayed that possibility by
about three years, according to Agnew.
If timekeeping organizations do eventually decide to add a negative leap second, the adjustment could disrupt
computer networks. Adding or subtracting leap seconds has the potential to disrupt satellite, financial, and
energy transmission systems that rely on extremely precise timing.
How does the Greenland seem to change from satellite images?
Greenland Ice Sheet, the single ice sheet or glacier covering about 80 percent of the island of Greenland and the
largest ice mass in the Northern Hemisphere, globally second in size to only the ice mass that covers Antarctica.
According to Britannica, the Greenland Ice Sheet is protected by cold waters of mostly Arctic origin against the
temperate Atlantic waters from the southeast. In volume, it contains 12 percent of the world’s glacier ice, and,
if it completely melted, the sea level would rise 24 feet (7.4 meters).
The decrease in mass of the Greenland Ice Sheet has been extensively recorded since the 1990s, with the pace of
ice loss accelerating notably in the 21st century. This decline is primarily attributed to various factors
affecting the surface mass balance (SMB) of the ice sheet, including changes in solar radiation, air temperature,
precipitation levels, and substantial losses from iceberg calving.
As melting persists, fjords are widening, allowing warm air to penetrate glacier bases, further hastening glacier
movement and leading to increased iceberg discharges. Consequently, the Greenland Ice Sheet is estimated to have
contributed 0.4 inches (10.6 mm) to the global rise in sea levels since the 1990s.
How did the sea ice area and extent change in the North Pole and South Pole through the decades?
Back in 1979, the North Pole ice area measured approximately 70 thousand km². Since then, it has fluctuated over
the past 45 years, experiencing both decreases and increases. In 1983, there was a historical peak, with the ice
area reaching 95 thousand km². However, just 13 years ago, in 2011, the ice area dwindled to a mere 43 thousand
km². Thankfully, this year has brought a positive turn, with a recorded ice area of nearly 52 thousand km².
However, it's worth noting that this represents a 15% drop from the previous year.
The expanse of ice at the South Pole has traditionally surpassed that of the North Pole. In 1979, the ice covered
an area of approximately 129 thousand km². However, over time, there has been a consistent trend of ice loss. By
1992, the ice area had dwindled to about half its 1979 extent, measuring only 67.5 thousand km². Subsequently, the
ice area fluctuated, experiencing both increases and decreases, before rebounding to 114 thousand km² by 2011.
This year, there has been a notable increase compared to the previous year, with the ice area expanding from 61.2
to 85.8 thousand km².
Since 1979, a consistent pattern of decline has been observed in the extent of North Pole ice. Initially, in
1979, the ice extent decreased by 25.7% over the course of the year. However, subsequent years showed a lesser
percentage of loss. In the 1990s, the average annual loss decreased to 1.86%. Nevertheless, starting in the 2000s,
there was a noticeable increase in the average annual loss, reaching 3.43%.
The situation in the South Pole presents a slightly more positive picture compared to the North Pole. Over the
decades, there has generally been an upward trend in the ice area for most years. Despite a significant decrease
in 1979, with a record loss of 111% of the extent, there was nearly a 23% increase just two years later. Since
then, there has been a gradual increase in ice extent each year, averaging around 2.2% until recent times However,
this upward trend came to a halt in 2021. In the past two years (2022 and 2023), there has been an average loss of
0.4% in ice extent.
So...?
Whether or not clocks undergo adjustments, the notion that melting polar ice is influencing Earth's rotation
underscores the gravity of the issue. Previous research has already highlighted the profound repercussions of ice
loss on coastal communities.
Scientists anticipate a hastening of sea level rise as the climate continues to warm—a process projected to
persist over centuries. In a report released last year, leading polar researchers sounded the alarm, warning of
the potential collapse of crucial ice sheets and urging coastal communities to brace themselves for substantial
sea level increases. Should global temperatures rise by 2 degrees Celsius, experts caution that the planet could
face a staggering rise of over 40 feet in sea levels.
