Science & Tech · Science & Environment · 4 hrs ago
Melting polar ice is changing Earth's solid shape
Earth is not a perfect sphere: its rotation makes it slightly flatter at the poles and wider around the equator.
A study found Earth's solid surface is becoming rounder as polar ice melts and shifts mass across the planet.
The research used satellite navigation measurements and found the poles rose while the equatorial bulge shrank by about 1 millimeter a year from 2011 to 2015.
That rate was faster than in 1997–2000, when the change was about 0.5 millimeters a year.
Melting ice reduces pressure on the Earth's crust, allowing the surface near the poles to rise, while changing mass also affects the equator.
The oceans behave differently from the solid Earth: when both are counted, Earth becomes slightly flatter because seawater bulges more around the equator.
The redistribution of mass has also been linked to a slower Earth rotation.
Researchers can combine satellite and gravity measurements to track the effects of melting ice in Greenland and Antarctica and changing ocean water.
A study reports that melting polar ice is changing Earth’s solid shape, with polar regions rising and the equatorial bulge shrinking.
The changes were about 1 millimeter per year from 2011 to 2015, faster than the rate measured from 1997 to 2000.
The researchers say melting ice reduces pressure on Earth’s crust, allowing the surface to rise as mass shifts.
When the oceans are included, Earth is becoming flatter by about 0.8 millimeters per year because seawater bulges around the equator.
The study used satellite navigation measurements and gravity-field observations to track changes linked to climate change.
- Who
- Researchers including Christoforos Kotsakis, a geodesy professor at Aristotle University of Thessaloniki, studied the changes.
- What
- Melting polar ice is changing Earth’s solid shape, raising the polar regions and reducing the equatorial bulge.
- When
- The reported change was about 1 millimeter per year during 2011 to 2015. The study was published on September 9, 2026.
- Where
- The changes involve Earth’s polar regions and equatorial region, including ice loss in Greenland and Antarctica.
- Why
- Melting ice reduces pressure on Earth’s crust and shifts mass from the polar regions, while redistributed seawater affects the equatorial bulge.
This story does not have two clearly opposing sides.
Earth’s solid shape became rounder at a rate of about 0.5 millimeters per year.
The polar regions rose and the equatorial bulge shrank by about 1 millimeter per year.
The study was published in the journal JGR Solid Earth.
- Solid-shape change, 2011–2015
- About 1 millimeter per year
- Earlier rate, 1997–2000
- About 0.5 millimeters per year
- Combined solid Earth and oceans
- Earth becomes flatter by about 0.8 millimeters per year
- Study journal
- JGR Solid Earth
- Researcher
- Christoforos Kotsakis, Aristotle University of Thessaloniki, Greece
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What people are saying
the phenomenon is similar to bread dough expanding again after being pressed with a finger