Featured Research

from universities, journals, and other organizations

Rise in temperatures and CO2 follow each other closely in climate change

Date:
July 23, 2012
Source:
University of Copenhagen
Summary:
The greatest climate change the world has seen in the last 100,000 years was the transition from the ice age to the warm interglacial period. New research indicates that, contrary to previous opinion, the rise in temperature and the rise in the atmospheric carbon dioxide follow each other closely in terms of time.

The research results show that the concentration of CO2 in the atmosphere followed the temperature in Antarctica closely throughout the shift from ice age to interglacial in the period 19-11,000 years before the present. The green curve shows the temperature from measurements from the 5 ice cores marked on the map. The red and blue curves show the atmospheric CO2 content in the air bubbles in the ice cores from the two bores at Siple Dome (red) and Byrd (blue). The analysis shows that the CO2 concentration follows the increase in temperature with a delay of no more than a few hundred years. That the CO2 concentration in the atmosphere follows the Antarctic tempera- ture so closely suggests that processes in the ocean around Antarctica play an important role in the rise in CO2.
Credit: Image courtesy of University of Copenhagen

The greatest climate change the world has seen in the last 100,000 years was the transition from the ice age to the warm interglacial period. New research from the Niels Bohr Institute at the University of Copenhagen indicates that, contrary to previous opinion, the rise in temperature and the rise in the atmospheric CO2 follow each other closely in terms of time. The results have been published in the scientific journal, Climate of the Past.

In the warmer climate the atmospheric content of CO2 is naturally higher. The gas CO2 (carbon dioxide) is a green-house gas that absorbs heat radiation from Earth and thus keeps Earth warm. In the shift between ice ages and interglacial periods the atmospheric content of CO2 helps to intensify the natural climate variations.

It had previously been thought that as the temperature began to rise at the end of the ice age approximately 19,000 years ago, an increase in the amount of CO2 in the atmosphere followed with a delay of up to 1,000 years.

"Our analyses of ice cores from the ice sheet in Antarctica shows that the concentration of CO2 in the atmosphere follows the rise in Antarctic temperatures very closely and is staggered by a few hundred years at most," explains Sune Olander Rasmussen, Associate Professor and centre coordinator at the Centre for Ice and Climate at the Niels Bohr Institute at the University of Copenhagen.

Deep-sea's important role

The research, which was carried out in collaboration with researchers from the University of Tasmania in Australia, is based on measurements of ice cores from five boreholes through the ice sheet in Antarctica. The ice sheet is formed by snow that doesn't melt, but remains year after year and is gradually compressed into kilometers thick ice. During the compression, air is trapped between the snowflakes and as a result the ice contains tiny samples of ancient atmospheres. The composition of the ice also shows what the temperature was when the snow fell, so the ice is an archive of past climate and atmospheric composition.

"The ice cores show a nearly synchronous relationship between the temperature in Antarctica and the atmospheric content of CO2, and this suggests that it is the processes in the deep-sea around Antarctica that play an important role in the CO2 increase," explains Sune Olander Rasmussen.

He explains that one of the theories is that when Antarctica warms up, there will be stronger winds over the Southern Ocean and the winds pump more water up from the deep bottom layers in the ocean where there is a high content of CO2 from all of the small organisms that die and fall down to the sea floor and rot. When strong winds blow over the Southern Ocean, the ocean circulation brings more of the CO2-rich bottom water up to the surface and a portion of this CO2 is released into the atmosphere. This process links temperature and CO2 together and the new results suggest that the linking is closer and happens faster than previously believed.

Climatic impact

The global temperature changed naturally because of the changing solar radiation caused by variations in Earth's orbit around the Sun, Earth's tilt and the orientation of Earth's axis. These are called the Milankowitch cycles and occur in periods of approximately 100,000, 42,000, and 22,000 years. These are the cycles that cause Earth's climate to shift between long ice ages of approximately 100,000 years and warm interglacial periods, typically 10,000 -- 15,000 years. The natural warming of the climate was intensified by the increased amount of CO2 in the atmosphere.

"What we are observing in the present day is the mankind has caused the CO2 content in the atmosphere to rise as much in just 150 years as it rose over 8,000 years during the transition from the last ice age to the current interglacial period and that can bring the Earth's climate out of balance," explains Sune Olander Rasmussen, adding: "That is why it is even more important that we have a good grip on which processes caused the climate of the past to change, because the same processes may operate in addition to the anthropogenic changes we see today. In this way the climate of the past helps us to understand how the various parts of the climate systems interact and what we can expect in the future."


Story Source:

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


Journal Reference:

  1. J. B. Pedro, S. O. Rasmussen, T. D. van Ommen. Tightened constraints on the time-lag between Antarctic temperature and CO2 during the last deglaciation. Climate of the Past, 2012; 8 (4): 1213 DOI: 10.5194/cp-8-1213-2012

Cite This Page:

University of Copenhagen. "Rise in temperatures and CO2 follow each other closely in climate change." ScienceDaily. ScienceDaily, 23 July 2012. <www.sciencedaily.com/releases/2012/07/120723162707.htm>.
University of Copenhagen. (2012, July 23). Rise in temperatures and CO2 follow each other closely in climate change. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2012/07/120723162707.htm
University of Copenhagen. "Rise in temperatures and CO2 follow each other closely in climate change." ScienceDaily. www.sciencedaily.com/releases/2012/07/120723162707.htm (accessed July 25, 2014).

Share This




More Earth & Climate News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Goma Cheese Brings Whiff of New Hope to DRC

Goma Cheese Brings Whiff of New Hope to DRC

Reuters - Business Video Online (July 24, 2014) The eastern region of the Democratic Republic of Congo, mainly known for conflict and instability, is an unlikely place for the production of fine cheese. But a farm in the village of Masisi, in North Kivu is slowly transforming perceptions of the area. Known simply as Goma cheese, the Congolese version of Dutch gouda has gained popularity through out the region. Ciara Sutton reports. Video provided by Reuters
Powered by NewsLook.com
Bill Gates: Health, Agriculture Key to Africa's Development

Bill Gates: Health, Agriculture Key to Africa's Development

AFP (July 24, 2014) Health and agriculture development are key if African countries are to overcome poverty and grow, US software billionaire Bill Gates said Thursday, as he received an honourary degree in Ethiopia. Duration: 00:36 Video provided by AFP
Powered by NewsLook.com
Higgins Breaks Record at Mt. Washington

Higgins Breaks Record at Mt. Washington

Driving Sports (July 24, 2014) Subaru Rally Team USA drivers David Higgins and Travis Pastrana face off against a global contingent of racers at the annual Mt. Washington Hillclimb in New Hampshire. Includes exclusive in-car footage from Higgins' record attempt. Video provided by Driving Sports
Powered by NewsLook.com
Storm Kills Three, Injures 20 at Virginia Campground

Storm Kills Three, Injures 20 at Virginia Campground

Reuters - US Online Video (July 24, 2014) A likely tornado tears through an eastern Virginia campground, killing three and injuring at least 20. Linda So 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:
from the past week

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