How global warming is literally making your day longer
Solving a scientific mystery over 20 years old, a team of Harvard researchers published a paper proving global warming's role in slowing the Earth's rotation.
The Thwaites Glacier in Antarctica is seen in this undated handout NASA image. The melting of glaciers caused by the world's rising temperatures appears to be causing a slight slowing of the Earth's rotation in another illustration of the far-reaching impact of global climate change, scientists said December 10, 2015.
NASA/Reuters
Melting glaciers caused by global warming will likely impact the Earth鈥檚 rotation, researchers suggest Friday in the journal Science Advances.聽
Researchers at Harvard University suggest the duration of the Earth鈥檚 day has over the past 100 years. Because, as atmospheric temperature rises and ice from the poles melts into the ocean, the weight of the planet鈥檚 water shifts from Earth鈥檚 axis to the Equator, causing the planet鈥檚 rotation to wobble and slow.
And when the Earth鈥檚 rotation slows, the days get longer.
鈥淏ecause glaciers are at high latitudes, from these high latitudes towards lower latitudes, and like a figure skater who moves his or her arms away from their body, this acts to slow the rotation rate of the Earth,鈥� Harvard University geophysicist and lead author Jerry Mitrovica told Reuters.聽
Additionally, glacial melt will make the Earth鈥檚 rotation wobble because 鈥渢he melting of glaciers isn鈥檛 perfectly symmetrical, and the than others,鈥� Mitrovica told The Washington Post.聽聽
Building off of research from a 2002 paper by oceanographer Walter Munk, Mitrovica and his team solved 鈥淢unk鈥檚 enigma,鈥� an early suggestion that melting glaciers were changing the Earth鈥檚 rotation. Dr. Munk knew that the Earth鈥檚 rotation had changed, and he knew sea-level rise had occurred, and while he knew the two were related he couldn鈥檛 make his data prove it.聽
Consequently, Munk predicted that melting polar ice caps would actually make the Earth's days shorter, because melting removes the weight of ice from the poles and , adding more mass to the poles and causing the planet to聽spin more quickly.
But to officially solve Munk鈥檚 original thesis, Mitrovica鈥檚 team lowered Munk鈥檚 estimate of sea level rise over the 20th聽century by 30 percent (equating to 1 or 1.5 millimeter each year). They also updated Munk鈥檚 model to account for Earth鈥檚 less-than-perfectly-spherical shape during the Ice Age and underestimating glaciers鈥� ability to deform underlying rock in the long term.聽
And most importantly, Munk did not account for the Earth鈥檚 liquid core, which plays a huge role in slowing the planet鈥檚 rotation.
鈥淚t鈥檚 like ,鈥� Mathieu Dumberry, a physics professor at the University of Alberta, told CBC news. 鈥淭he hamster runs in one direction and the wheel [turns] in the other.鈥�
鈥淲hat we believe in regard to melting of glaciers in the 20th聽century is [as] measured by satellites and astronomical methods,鈥� Mitrovica told Live Science. 鈥淏y resolving Munk鈥檚 enigma, we further strengthen the already-strong argument that we are impacting climate.鈥澛�
And while the change is modest, experts say it should not be underrated.
鈥淭he period of a day is but that will accelerate as the melting increases,鈥� Mitrovica told The Guardian. 鈥淧eople won鈥檛 be running from their houses screaming about an extra millisecond but it adds yet further confirmation of what we are doing to our environment. It鈥檚 another fingerprint.鈥�
The volume of Earth鈥檚 glaciers is predicted to decrease between 15 and 85 percent by 2100, further slowing Earth鈥檚 rotation.聽