NASA: “Climate Change Shifting Earth’s Motion on Its Polar Axis”

 

 

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Melting ice sheets in Greenland are changing the distribution of weight on Earth, according to a study by NASA scientists, that has caused both the North Pole and the wobble, which is called polar motion, to change course. Scientists and navigators have been accurately measuring the true pole and polar motion since 1899 and for almost the entire 20th century they migrated a bit toward Canada. But that has changed with this century and now it's moving toward England, said study lead author Surendra Adhikari at NASA's Jet Propulsion Lab.

 


"The recent shift from the 20th-century direction is very dramatic," Adhikari said in a study published Friday in the journal Science Advances.

While scientists say the shift is harmless, it is meaningful. Jonathan Overpeck, professor of geosciences at the University of Arizona who wasn't part of the study, said "this highlights how real and profoundly large an impact humans are having on the planet."

Evidence for a new geological epoch which marks the impact of human activity on the Earth is now overwhelming according to a paper released in January 2016 by an international group of geoscientists. The Anthropocene, which is argued to start in the mid-20th Century, is marked by the spread of materials such as aluminium, concrete, plastic, fly ash and fallout from nuclear testing across the planet, coincident with elevated greenhouse gas emissions and unprecedented trans-global species invasions. 

The scientists are studying whether human activity has driven the Earth into a new geological epoch – the Anthropocene. They ask: to what extent are human actions recorded as measurable signals in geological strata, and is the Anthropocene world markedly different from the stable Holocene Epoch of the last 11,700 years that allowed human civilization to develop?

The Holocene Epoch has been a time during which human societies advanced by gradually domesticating the land to increase food production, built urban settlements and became proficient at developing the water, mineral and energy resources of the planet. The proposed Anthropocene Epoch, however, is marked as a time of rapid environmental change brought on by the impact of a surge in human population and increased consumption during the 'Great Acceleration' of the mid-20th century.

 

Greenland

 

Since 2003, Greenland has lost on average more than 600 trillion pounds of ice a year and that affects the way the Earth wobbles in a manner similar to a figure skater lifting one leg while spinning, said NASA scientist Eirk Ivins, the study's co-author.

Ivins said he likes to think of it as a billion trucks each year dumping ice out of Greenland. On top of that, West Antarctica loses 275 trillion pounds of ice and East Antarctica gains about 165 trillion pounds of ice yearly, helping tilt the wobble further, Ivins said.

They all combine to pull polar motion toward the east, Adhikari said.

Jianli Chen, a senior research scientist at the University of Texas' Center for Space Research, first attributed the pole shift to climate change in 2013 and he said this new study takes his work a step further. "There is nothing to worry about," said Chen, who wasn't part of the NASA study. "It is just another interesting effect of climate change."

The Daily Galaxy via advances.sciencemag.org

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