Melting ice in Antarctica and Greenland is adding volume to the oceans and this extra water is being pulled towards the Equator, adding to the girth at the widest part of our planet, according to scientists.
Earth had been 'slimming down' following the Ice Age, which finished about 20,000 years ago.
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During this geological period of long-term reduction in the temperature of the Earth's surface and atmosphere, the weight of ice sheets was so great that they deformed the Earth's crust and mantle, causing it to bulge at the middle.
The Earth isn't completely spherical - land at the North Pole is a number of kilometres nearer to the core of the planet than land at the Equator.
And it was believed that the rebound effect following the Ice Age would result in our planet becoming more of a perfect sphere.
The 'bulge' at the Equator had been shrinking by less than a millimetre a year, according to National Geographic.
But by looking at measurements from the Gravity Recovery and Climate Experiment (GRACE) satellites, it was found that this effect was reversing.
'There's something else going on that offsets [the shrinking of the Earth's girth],' said John Wahr, a geophysicist at the University of Colorado.
The rate of melting ice at the North and South Poles - which totals 382 billion tons of ice a year - is counteracting the 'slimming' effect.
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