Humans Are Causing the Earth To Wobble More Than It Should, NASA Finds (bgr.com)

Iwastheone shares a report from BGR: When looking at the Earth from afar it appears to be a perfect sphere, but that actually isn't the case. Because Earth isn't uniform on all sides due to land masses that shift and change over time, our planet actually wobbles a bit when it spins. Now, a new study by researchers with NASA's Jet Propulsion Laboratory and several universities and science centers has pinpointed the causes of Earth's imperfect spin, called "polar motion," and they found that humans are contributing to it. The researchers used a wealth of data gathered over 100 years to build mathematical models to trace the causes of the wobble and found that three factors are at play, and mankind is responsible for one of them. Two of the three factors identified by the scientists are glacial rebound and mantle convection. Glacial rebound happens when thick ice sheets physically push down on land masses, compressing them, but then release that pressure upon melting. The land then balloons back up over time, causing Earth's spin to wobble as if slightly off-axis. The effects of the last ice age, which would have compressed a huge amount of land across many continents, is still being felt today in the form of glacial rebound.

Mantle convection, the other uncontrollable factor in Earth's wobble, relates to our planet's inner workings. The plates on Earth's surface are in constant flux due to the movement of liquid rock far beneath our feet. The researchers believe these currents also contribute to the planet's imperfect spin. The third and final factor identified by the scientists is the massive loss of ice on Greenland and other areas, which is the direct result of global warming thanks to human activities. The researchers estimate that Greenland has lost roughly 7,500 gigatons, or 7,500,000,000,000 metric tons of ice due to global warming. All that ice loss has happened in the 20th century, and greenhouse gas production has been cited as the primary culprit. Losing all that mass has caused a significant shift on the planet and has contributed to the wobble as well.

Comments

Contradiction

[ichthus]

The effects of the last ice age, which would have compressed a huge amount of land across many continents, is still being felt today in the form of glacial rebound....
{snip}
The third and final factor identified by the scientists is ... the direct result of global warming thanks to human activities.

So... acknowledgment that we're still coming out of the last ice age (you know, warming), but (and in the very next breath, mind you) blaming (in its entirety) this warming solely on human activity. How fucking stupid do they think we are? ...

Re:Contradiction

[Plus1Entropy]

They are speaking of 2 different effects, both caused by the melting of ice.

The first effect is due to how the land responds to the ice melting. This continues long after the ice has melted, because the land does not decompress instantly. This is not (really) about glaciers that are melting today, the land is rebounding from glaciers which melted millennia ago.

The second effect is due simply to the loss of the ice itself. As stated in TFS, the 7500Gtons is only over the last 100 years. That much mass loss in a fairly localized area was enough to make a significant contribution to the movement of Earth's center of mass, impacting the wobble.

Finally, it's not the direction so much as the rate. Yes, we're coming out of an ice age, so we would expect average temperatures to gradually climb. However, what we have seen is that the climb has accelerated. Specifically, it has accelerated during the time that we have become industrialized. That acceleration means that certain effects will be more extreme, and we will have less time to adapt or prepare for them.

This is not just true of the climate, but of any non-linear dynamic system (aka everything). When a system moves from one state to another, there are high frequency effects introduced. The faster the system transitions, the more pronounced those effects are.

Yo Mamma

[alvinrod]

Yo mamma so fat, she makes the earth wobble more than it should.

We all know that's the real cause.

Popcorn time!

[Opportunist]

Get out your bag of popcorn folks and grab a soda, the astroturfers are on stage again! What are they gonna give us today? "It's not man made"? "It doensn't happen"? Or are we going to be entertained by a new conspiracy theory around the evil scientist that gets rich from wanting to change our way of life?

Anyhow, we know it's gonna be a blast! Let the show begin!