Featured Research

from universities, journals, and other organizations

Before Fossil Fuels, Earth's Minerals Kept Carbon Dioxide In Check

Date:
April 30, 2008
Source:
Carnegie Institution
Summary:
Over millions of years carbon dioxide levels in the atmosphere have been moderated by a finely-tuned natural feedback system -- a system that human emissions have recently overwhelmed. Scientists have now linked the pre-human stability to connections between carbon dioxide in the atmosphere and the breakdown of minerals in the Earth's crust.

Over millions of years carbon dioxide levels in the atmosphere have been moderated by a finely-tuned natural feedback system-- a system that human emissions have recently overwhelmed. A joint University of Hawaii / Carnegie Institution study published in the advance online edition of Nature Geoscience links the pre-human stability to connections between carbon dioxide in the atmosphere and the breakdown of minerals in the Earth's crust. While the process occurs far too slowly to have halted the historical buildup of carbon dioxide from human sources, the finding gives scientists new insights into the complexities of the carbon cycle.

Ken Caldeira of the Carnegie Institution's Department of Global Ecology and Richard Zeebe of the University of Hawaii studied levels of carbon dioxide in the atmosphere over the past 610,000 years using data from gas bubbles trapped in Antarctic ice cores. They used these records, plus geochemical data from ocean sediments, to model how carbon dioxide released into the atmosphere by volcanoes and other natural sources is ultimately recycled via carbon-bearing minerals back into the crust.

When carbon dioxide levels in the atmosphere rise, the chemical reactions that break down silicate minerals in soils are accelerated. Among the products of these reactions are calcium ions, which dissolve in water and are washed to the ocean by rivers. Marine organisms such as mollusks combine the calcium ions with dissolved carbon dioxide to make their shells (calcium carbonate), which removes both calcium and carbon dioxide from the ocean, restoring the balance.

The researchers found that over hundreds of thousands of years the equilibrium between carbon dioxide input and removal was never more than one to two percent out of balance, a strong indication of a natural feedback system. This natural feedback acts as a thermostat which is critical for the long-term stability of climate. During Earth's history it has probably helped to prevent runaway greenhouse and icehouse conditions over time scales of millions to billions of years -- a prerequisite for sustaining liquid water on Earth's surface.

"The system is finely in tune," says Caldeira. "That one or two percent imbalance works out to an average imbalance in natural carbon dioxide emissions that is thousands of times smaller than our current emissions from industry and the destruction of forests."

Previous researchers had suggested that such a system existed, but Caldeira and Zeebe's study provides the first observational evidence supporting the theory, and confirms its role in stabilizing the carbon cycle. But because it operates over such a long time scale--the time scale over which landscapes are eroded and washed to the sea--this geological feedback system offers little comfort with respect to the current climate crisis.

Carbon dioxide is added naturally to the atmosphere and oceans from volcanoes and hydrothermal vents at a rate of about 0.1 billion tons of carbon each year. Human industrial activity and destruction of forests is adding carbon about 100 times faster, approximately 10 billion tons of carbon each year.

"The imbalance in the carbon cycle that we are creating with our emissions is huge compared to the kinds of imbalances seen over the time of the glacial ice core records," says Caldeira. "We are emitting CO2 far too fast to expect mother nature to mop up our mess anytime soon. Continued burning of coal, oil and gas will result in long-term changes to our climate and to ocean chemistry, lasting many thousands of years."


Story Source:

The above story is based on materials provided by Carnegie Institution. Note: Materials may be edited for content and length.


Cite This Page:

Carnegie Institution. "Before Fossil Fuels, Earth's Minerals Kept Carbon Dioxide In Check." ScienceDaily. ScienceDaily, 30 April 2008. <www.sciencedaily.com/releases/2008/04/080429095100.htm>.
Carnegie Institution. (2008, April 30). Before Fossil Fuels, Earth's Minerals Kept Carbon Dioxide In Check. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2008/04/080429095100.htm
Carnegie Institution. "Before Fossil Fuels, Earth's Minerals Kept Carbon Dioxide In Check." ScienceDaily. www.sciencedaily.com/releases/2008/04/080429095100.htm (accessed October 21, 2014).

Share This



More Earth & Climate News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Traditional Farming Methods Gaining Ground in Mali

Traditional Farming Methods Gaining Ground in Mali

AFP (Oct. 20, 2014) — He is leading a one man agricultural revolution in Mali - Oumar Diatabe uses traditional farming methods to get the most out of his land and is teaching others across the country how to do the same. Duration: 01:44 Video provided by AFP
Powered by NewsLook.com
Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

3BL Media (Oct. 20, 2014) — Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-fuel Impala Video provided by 3BL
Powered by NewsLook.com
White Rhino's Death In Kenya Means Just 6 Are Left

White Rhino's Death In Kenya Means Just 6 Are Left

Newsy (Oct. 20, 2014) — Suni, a rare northern white rhino at Ol Pejeta Conservancy, died Friday. This, as many media have pointed out, leaves people fearing extinction. Video provided by Newsy
Powered by NewsLook.com
New Organic Fertilizer Helps Reforestation of Monarch Butterflies’ Winter Retreat

New Organic Fertilizer Helps Reforestation of Monarch Butterflies’ Winter Retreat

Reuters - Innovations Video Online (Oct. 20, 2014) — Using an organic fertiliser, a conservationist from the National Autonomous University of Mexico (UNAM), leads an award-winning project to reforest the sanctuary of monarch butterflies. Sharon Reich reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins