Social Media Sidebar

Announcement

Please sign up, comment on articles and bring your friends!

Current poll

PlanetTech is asking:

What do you think about our new web site?

Love it, indeed
Really good solution
Same as old one
The old one was better
This is a new option

Quote of the day

'By far the greatest danger of Artificial Intelligence is that people conclude too early that they understand it'

 

Eliezer Yudkowsky

Melting of ice lid caused release of CO2 at the end of the ice age

RATE THIS! +32
Posted in Science on 5th Jan, 2016 07:50 PM by AlexMuller

A study reconstructing conditions at the end of the last ice age suggests that as the Antarctic ice melted, massive amounts of CO2 was released into the atmosphere. The study includes the first detailed reconstruction of the Southern Ocean density of the period and identified how it changed as the Earth warmed.

 

It suggests a massive reorganisation of ocean temperature and salinity, but finds that this was not the driver of increased concentration of carbon dioxide in the atmosphere. 

The ocean is made up of different layers of varying densities and chemical compositions. During the last ice age, it was thought that the deepest part of the ocean was made up of very salty, dense water, which was capable of trapping a lot of CO2. Scientists believed that a decrease in the density of this deep water resulted in the release of CO2 from the deep ocean to the atmosphere.
 
However, the new findings suggest that although a decrease in the density of the deep ocean did occur, it happened much later than the rise in atmospheric CO2, suggesting that other mechanisms must be responsible for the release of CO2 from the oceans at the end of the last ice age.
 
"We set out to test the idea that a decrease in ocean density resulted in a rise in CO2 by reconstructing how it changed across time periods when the Earth was warming," said the paper's lead author Jenny Roberts, a PhD student in Cambridge's Department of Earth Sciences who is also a member of the British Antarctic Survey. "However what we found was not what we were expecting to see."
 
In order to determine how the oceans have changed over time and to identify what might have caused the massive release of CO2, the researchers studied the chemical composition of microscopic shelled animals that have been buried deep in ocean sediment since the end of the ice age.
 
Like layers of snow, the shells of these tiny animals, known as foraminifera, contain clues about what the ocean was like while they were alive, allowing the researchers to reconstruct how the ocean changed as the ice age was ending.
 
They found that during the cold glacial periods, the deepest water was significantly denser than it is today. However, what was unexpected was the timing of the reduction in the deep ocean density, which happened some 5,000 years after the initial increase in CO2, meaning that the density decrease couldn't be responsible for releasing CO2 to the atmosphere.
 
"Before this study there were these two observations, the first was that glacial deep water was really salty and dense, and the second that it also contained a lot of CO2, and the community put two and two together and said these two observations must be linked," said Roberts. "But it was only through doing our study, and looking at the change in both density and CO2 across the deglaciation, that we found they actually weren't linked. This surprised us all."
 
Through examination of the shells, the researchers found that changes in CO2 and density are not nearly as tightly linked as previously thought, suggesting something else must be causing CO2 to be released from the ocean.
 
Like a bottle of wine with a cork, sea ice can prevent CO2-rich water from releasing its CO2 to the atmosphere. The Southern Ocean is a key area of exchange of CO2 between the ocean and atmosphere. The expansion of sea ice during the last ice age acted as a 'lid' on the Southern Ocean, preventing CO2 from escaping. The researchers suggest that the retreat of this sea ice lid at the end of the last ice age uncorked this vintage CO2, resulting in an increase in carbon dioxide in the atmosphere.
 
"Although conditions at the end of the last ice age were very different to today, this study highlights the importance that dynamic features such as sea ice have on regulating the climate system, and emphasises the need for improved understanding and prediction as we head into our ever warming world," said Roberts.

Tags: iceglobal warmingCO2ice ageclimateplanetEarthresearch

Read original article » Back to category

Comments

Author: Guest
Posted: 2016-01-06
+1
Changes in the environment include natural variations that are separate from human activity - indeed, these have to be better understood Reply


 

Recent headlines

  • Posted in Business on 2017-03-28 14:55:07
    Bots shift towards AI and garner $24 billion of investment..read more
    Posted in Science on 2017-03-28 14:45:33
    Musk launches company to pursue 'neural lace'.....read more
    Posted in Science on 2017-03-28 14:29:14
    No one knows what to do with the International Space Station..read more
    Posted in Business on 2017-03-27 19:48:26
    Tech world debate on robots and jobs heats up..read more
    Posted in Science on 2017-03-27 19:37:58
    Chemical energy storage with water heating solar panels.....read more
Posted in Business on 2013-10-10 01:33
China is working towards a manned lunar mission in about.....read more
Posted in Business on 2013-10-20 07:17
Spacex says China is their main competitor for commercial.....read more
Posted in Software on 2013-10-20 06:43
Pirate Bay Browser Clocks 1,000,000 Downloads..read more
Posted in Medicine on 2013-10-10 02:10
Google reportedly investing hundreds of millions into new.....read more
Posted in Medicine on 2013-10-14 03:13
Endothelial Cells Can Repair and Regenerate Organs,.....read more
Posted in Science on 01.01.2010
Spacex says China is their main competitor for commercial.....read more
Posted in Science on 01.01.2010
Staring at Your Phone Could Be Making You Short Sighted..read more
Posted in Science on 01.01.2010
Oculus Rift virtual reality headset coming to mobile, but.....read more
Posted in Science on 01.01.2010
China is working towards a manned lunar mission in about.....read more
Posted in Science on 01.01.2010
Delivering drugs via nanoparticles to target mitochondria..read more

Recent Blog Posts

  • Posted by AlexMuller
    Intensive medical treatment can reverse type 2 diabetes..read more
    Posted by AlexMuller
    Daily consumption of tea protects the elderly from cognitive.....read more
    Posted by AlexMuller
    New analysis method of metabolites accurately predicts whether.....read more
    Posted by AlexMuller
    Unproven stem cell 'therapy' blinds three patients at Florida.....read more
    Posted by AlexMuller
    Indigenous South American group has healthiest arteries of all.....read more

Login to your Account

Login to your PlanetTech Account here

Username:
Password:
Remember me
or

Create a New Account

You just need username and password

The following errors occured:
Username:
Email:
Password:
Verify password:
Remember me