According To New NASA Data Humans Have Literally Knocked Planet Earth Off-Balance

Wednesday, 26 September 2018 - 1:01PM
Earth
Wednesday, 26 September 2018 - 1:01PM
According To New NASA Data Humans Have Literally Knocked Planet Earth Off-Balance
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Pixabay Composite
If you paid attention in science class, you know that the Earth isn't a perfect sphere – it's an "oblate spheroid" that bulges at the equator. If you're a real science nerd, though, you may have heard of the Chandler wobble: a phenomenon unrelated to the sitcom Friends where the Earth's axis of rotation changes (or "wobbles") by tiny amounts, a process called "polar motion." The source of these wobbles has been a mystery for years, but NASA recently announced that they've got a lock on it. Three big factors are causing the anomalies in Earth's spin: glacial rebound, molten convection, and...

Humans.

If you imagine the Earth as a big, spinning top with a bunch of continents on it, you can understand how adding weight to one side (say, the southwestern hemisphere) is going to cause the whole top to spin a little off balance. This is essentially what's happening, but – instead of adding weight – huge pieces of the Earth are actually moving around.

In the case of glacial rebound, landmasses are rising due to the weight of glaciers disappearing during the last Ice Age, shifting their weight toward the outer parts of the Earth. Meanwhile, the tectonic plates beneath Earth's surface are in constant motion, shifting their weight around as they're carried by currents of molten rock.

Then there's us humans. According to NASA, human-driven climate change has caused Greenland to lose 7,500,000,000,000 metric tons of ice over the past 100 years, which has triggered its own kind of glacial rebound. According to NASA: "With these three broad contributors identified, scientists can distinguish mass changes and polar motion caused by long-term Earth processes over which we have little control from those caused by climate change. They now know that if Greenland's ice loss accelerates, polar motion likely will, too."

It's pretty awe-inspiring to know that human actions have the potential to literally throw the planet off balance but, on the list of human accomplishments, it's probably not our proudest.

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