backtop


Print 48 comment(s) - last by tng.. on Mar 30 at 5:59 PM


  (Source: img.wendmag.com)
Study blames human activity for climate change

NASA and international university researchers claim that humans have thrown off the balance between the Earth's rotation, surface air temperatures and movements in its molten core through our contribution of greenhouse gases.

Those included in the study were Jean Dickey and Steven Marcus from NASA's Jet Propulsion Laboratory, along with Olivier de Viron, from the Universite Paris Diderot and Institut de Physique du Globe de Paris in France.

It is well known that an Earth day consists of 24 hours, which is the time it takes for the Earth to make one full rotation. Over a year's time, seasonal changes occur due to energy exchanges between fluid motions of the Earth's atmosphere, the oceans and solid Earth itself, which changes the length of a day by about 1 millisecond. In addition, the length of a day on Earth can vary over longer timescales such as interannual timescales (two to 10 years) or decadal timescales (10 years).

But Earth’s oceans or motions of its atmosphere cannot explain the variances in the length of day over longer timescales. Instead, longer fluctuations are explained by the flow of liquid iron within Earth's outer core, which interacts with the mantle to determine Earth's rotation. This is also where the Earth's magnetic field originates, and because researchers cannot observe the flows of liquid iron directly, the magnetic field is observed at the surface.  

Studies have shown that this liquid iron "oscillates in waves of motion that last for decades," and have timescales that resemble long fluctuations in Earth's day length. At the same time, other studies have shown that long variations in Earth's day length are closely related to fluctuations in Earth's average surface air temperature. 

In this study, the NASA/university team of researchers has linked Earth's rotation, surface air temperatures and the movement in its molten core. They did this by mapping existing data on yearly length-of-day observations and fluid movements within Earth's core against "two time series of annual global average surface temperature." One dated back to 1880 from NASA's Goddard Institute of Space Studies in New York, and the other dated back to 1860 from the United Kingdom's Met Office.  

According to the study, temperature changes not only occur naturally, but are also affected by human activities. So researchers used computer climate models of Earth's oceans and atmosphere to generate changes made by humans. Then, these temperature changes caused by human activities were removed from the overall total observed temperature records. What they found was that old temperature data coordinated with data on Earth's day length and movements of its core until 1930, but after that, surface air temperatures increased without corresponding changes in movements of the core or day length. According to the study, this deviation after 1930 is linked to increased levels of the human contribution of greenhouse gases.  

But the new temperature data that the researchers generated (which subtracted human activity from the equation) had a temperature record that coordinated with Earth's core movements and day length, showing how human activity has thrown the Earth's climate off balance. 

"The solid Earth plays a role, but the ultimate solution to addressing climate change remains in our hands," said Dickey. 

Dickey is unsure as to why these three variables correlate, but hypothesized that Earth's core movements might interfere with the magnetic fielding of charged particle fluxes, which may affect cloud formation. This affects how much sunlight the Earth absorbs and how much is reflected back into space. 

"Our research demonstrates that, for the past 160 years, decadal and longer-period changes in atmospheric temperature correspond to changes in Earth's length of day if we remove the very significant effect of atmospheric warming attributed to the buildup of greenhouse gases due to mankind's enterprise," said Dickey. "Our study implies that human influences on climate during the past 80 years mask the natural balance that exists among Earth's rotation, the core's angular momentum and the temperature at Earth's surface." 

This study was published in the Journal of Climate.



Comments     Threshold


This article is over a month old, voting and posting comments is disabled

By geddarkstorm on 3/14/2011 5:10:42 PM , Rating: 3
No, that's speculation, no matter what they want to call that, it's pure hand waving and conjecture. There is no friggin way the surface temperature of Earth, within the range of natural variability, is going to affect rotational speed.

However, what about the other way around? What about the frictional heat generated by the core and the mantle? Might THAT affect surface temperature of the Earth? Wouldn't that not only make senses, but follow the laws of physics that the other way would likely be breaking?

What makes more sense?


By Lexda on 3/15/2011 11:44:04 AM , Rating: 2
Tell me again why you believe "there's no friggin' way?" If you're trying to show an aura of competence regarding science, you're doing it wrong. I mean, personally, there's no friggin' way a bowling ball and a golf ball will fall at the same rates; it just doesn't make sense!

"The greatest words ever uttered by a scientist aren't 'Eureka!" but rather, 'Now that's funny...'"

Science isn't about proclaiming "But that's impossible!" It's about figuring out why something we previously thought was impossible actually occurs.


By geddarkstorm on 3/15/2011 5:34:56 PM , Rating: 2
They have absolutely no mechanism. Nor is there any mechanism in physics I know of. Perhaps I'm wrong, but think about heat transfer for a minute and spin dynamics between a solid and a fluid. Then look at the orders of magnitude difference between small fluctuations of 10C on the surface of the planet between the mass and temperature of the core/mantle.

Use your head for a second.

Now, what about the other direction? Could changes in the MASSIVE core of our planet rubbing against the MASSIVE mantle, affect within a few tenths of a degree C the temperature of the surface? Think for a minute, and do some empirical experiments of your own instead of of just swallowing whatever you're spoon fed.

As to your example, empirical evidence quickly showed they did fall at the same rate, nor was there no obvious violation of physics that would preclude them to do so, or any opposite, and far more likely mechanism. So don't go spouting off cliches without actually thinking about the issue.


By Lexda on 3/15/2011 6:16:02 PM , Rating: 2
I'm not trying to offer an explanation. I'm simply noting that all of my scientific training has taught me to not discard something simply because it doesn't meet my preconceptions.


By RedemptionAD on 3/16/2011 1:56:20 AM , Rating: 2
The law of probability says that nothing is impossable. It's just a matter of is it probable. No exceptions.


By geddarkstorm on 3/17/2011 1:17:49 PM , Rating: 2
And scientific training says outlandish speculation requires outlandish proof before it's anything more than. Or, that to be science in the first place, it must be testable. There's nothing testable about this, so it can't even be considered science. On the other hand, what we do know of physics contradicts this.

Could it be real? As the other person who replied to you said, of course; and our overarching theories get modified and changed by discoveries every year. But probable? No way. So should we freak out and start talking about this as if it were fact? NO. And that's where the danger lies, and that's where rationality needs to step in and put on the breaks.


"I mean, if you wanna break down someone's door, why don't you start with AT&T, for God sakes? They make your amazing phone unusable as a phone!" -- Jon Stewart on Apple and the iPhone














botimage
Copyright 2014 DailyTech LLC. - RSS Feed | Advertise | About Us | Ethics | FAQ | Terms, Conditions & Privacy Information | Kristopher Kubicki