Plate Nº 44 · recorded October 10, 2026
Earth & ClimateReported finding
Earth's Poles Are Rising About 1 Millimeter Per Year, Study Finds
Earth's poles are rising by as much as one millimeter per year, according to research highlighted by AGU on October 1, 2026, gradually nudging the planet toward a rounder shape.
By James Calloway3 min read662 words
In brief
- Earth's poles are rising by up to 1 millimeter per year, according to a study highlighted by AGU on October 1, 2026.
- Earth is an oblate spheroid, with an equatorial diameter of about 12,756 km and a polar diameter of about 12,714 km — a flattening of about 0.3 percent.
- At that rate, eliminating the 43-km polar-equatorial difference on its own would take roughly 43 million years.
- NASA's Artemis II crewed lunar flyby took place in April 2026, providing the imagery used alongside the AGU release.
- The AGU summary did not name the study's authors, institution, or journal of publication.
Earth's poles are lifting at a rate of up to one millimeter per year, a new study reports, gradually rounding a planet that has long been slightly squashed at its top and bottom.
The finding, highlighted October 1, 2026, by the American Geophysical Union (AGU), comes from research suggesting that the polar regions are rising relative to the equator. Earth is not a perfect sphere — it bulges outward near the equator and flattens at the poles, a shape called an oblate spheroid. If the poles climb while the equatorial bulge stays put, the planet inches toward a more uniform, rounded profile.
In the AGU news release, the finding was summarized directly: "our home planet is gradually getting rounder as the poles rise by up to a millimeter every year."
How round is Earth to begin with?
The difference between Earth's equatorial and polar radii is small but real. The equatorial diameter measures roughly 12,756 kilometers, about 43 kilometers larger than the polar diameter of about 12,714 kilometers. That works out to a flattening of roughly 0.3 percent — invisible to the eye, but easily detectable with satellites and precise geodesy.
A one-millimeter annual rise at the poles would take about 43 million years to erase that 43-kilometer gap on its own. In practice, the change is much slower than that comparison suggests, because most of the equatorial-to-polar difference reflects rotation and deep-Earth dynamics that this millimeter-scale signal does not address.
What could push the poles upward?
The AGU summary does not specify the driver. Several processes can shift mass at high latitudes:
- Glacial isostatic adjustment: Continents that once sat under massive ice sheets during the last ice age are still rebounding, slowly lifting land — and in some cases seafloor — thousands of years after the ice retreated. Scandinavia and Canada are classic examples.
- Ice mass changes: Loss of ice from Greenland and Antarctica redistributes water from high latitudes toward equatorial oceans.
- Deep-Earth convection: Slow movement of rock in the mantle can reshape the planet's gravity field and surface over geological time.
The combination of these effects, rather than any one alone, is likely what the researchers measured, though the original paper would be needed to confirm which dominates.
How do scientists measure a millimeter of pole movement?
Modern geodetic techniques can detect vertical changes of just a few millimeters across continents. The main tools include:
- GNSS networks: Arrays of ground receivers track their own position over time relative to orbiting satellites.
- Satellite altimetry: Spacecraft bounce radar or laser pulses off the ocean surface, mapping sea level with centimeter accuracy.
- Gravity-sensing missions: Satellites such as GRACE and its successor measure tiny variations in Earth's gravitational pull, which reveal how mass shifts around the planet.
Why does a millimeter matter?
A single millimeter per year is too small to affect daily life, weather, or sea level in the short term. The value of the measurement lies in what it reveals about the planet's interior and its response to surface change. Long-term geodetic records help researchers separate natural cycles — such as the slow rebound from past ice ages — from modern signals like ice-sheet loss or groundwater extraction.
The finding also gives an accessible way to talk about planetary shape. Earth looks like a blue marble in images from NASA's Artemis II, a crewed lunar flyby conducted in April 2026. (That mission's imagery, credited to NASA/Artemis II/JSC/ESRS/University of Texas at El Paso/Kevin M. Gill via Wikimedia Commons, accompanies the AGU release.) Behind the apparent roundness, geodesists keep finding that the planet is anything but static.
The study was released in conjunction with AGU's 2026 Annual Meeting; press registration for that gathering opened the same week. The AGU summary did not name the study's authors, institution, or journal, so independent verification of the methodology will have to wait for the underlying paper.
via agupubs.onlinelibrary.wiley.com (Original)
More from James Calloway
Show full bio
Staff writer covering marketplaces and e-commerce at SciBeat.
205 articles
Nearby plates
- Earth's Day Drifts by Milliseconds. The Culprit May Be the Inner Core.
- Hubble Spots a Sudden 10-Sided Wave at Saturn's South Pole
- African Superplume May Be Reshaping the East African Rift from Below
- Antarctica Gained 695 Billion Tons of Ice. The Trigger Was Thousands of Miles Away
- Arctic Melt Season Grew 40 Days Longer Since 1979—Then Stalled in 2010