Featured Research

from universities, journals, and other organizations

Earth more sensitive to carbon dioxide than previously thought

Date:
December 7, 2009
Source:
University of Bristol
Summary:
In the long term, the Earth's temperature may be 30-50 percent more sensitive to atmospheric carbon dioxide than has previously been estimated, reports a new study. The results show that components of the Earth's climate system that vary over long timescales -- such as land-ice and vegetation -- have an important effect on this temperature sensitivity, but these factors are often neglected in current climate models.

The temperature response of the Earth (in degrees C) to an increase in atmospheric carbon dioxide from pre-industrial levels (280 parts per million by volume) to higher levels (400 parts per million by volume). (a) shows predicted global temperatures when processes that adjust on relatively short-term timescales (for example sea-ice, clouds, and water vapour) are included in the model (b) includes additional long-tem processes that adjust on relatively long timescales (vegetation and land-ice).
Credit: Image courtesy of University of Bristol

In the long term, the Earth's temperature may be 30-50% more sensitive to atmospheric carbon dioxide than has previously been estimated, reports a new study published in Nature Geoscience.

The results show that components of the Earth's climate system that vary over long timescales -- such as land-ice and vegetation -- have an important effect on this temperature sensitivity, but these factors are often neglected in current climate models.

Dan Lunt, from the University of Bristol, and colleagues compared results from a global climate model to temperature reconstructions of the Earth's environment three million years ago when global temperatures and carbon dioxide concentrations were relatively high. The temperature reconstructions were derived using data from three million-year-old sediments on the ocean floor.

Lunt said, "We found that, given the concentrations of carbon dioxide prevailing three million years ago, the model originally predicted a significantly smaller temperature increase than that indicated by the reconstructions. This led us to review what was missing from the model."

The authors demonstrate that the increased temperatures indicated by the reconstructions can be explained if factors that vary over long timescales, such as land-ice and vegetation, are included in the model. This is primarily because changes in vegetation and ice lead to more sunlight being absorbed, which in turn increases warming.

Including these long-term processes in the model resulted in an increased temperature response of the Earth to carbon dioxide, indicating that the Earth's temperature is more sensitive to carbon dioxide than previously recognised. Climate models used by bodies such as the Intergovernmental Panel on Climate Change often do not fully include these long-term processes, thus these models do not entirely represent the sensitivity of the Earth's temperature to carbon dioxide.

Alan Haywood, a co-author on the study from the University of Leeds, said "If we want to avoid dangerous climate change, this high sensitivity of the Earth to carbon dioxide should be taken into account when defining targets for the long-term stabilisation of atmospheric greenhouse-gas concentrations."

Lunt added: "This study has shown that studying past climates can provide important insights into how the Earth might change in the future."

(a) shows predicted global temperatures when processes that adjust on relatively short-term timescales (for example sea-ice, clouds, and water vapour) are included in the model

(b) includes additional long-tem processes that adjust on relatively long timescales (vegetation and land-ice).

This research was funded by the Research Council UK and the British Antarctic Survey.


Story Source:

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


Journal Reference:

  1. Daniel J. Lunt, Alan M. Haywood, Gavin A. Schmidt, Ulrich Salzmann, Paul J. Valdes and Harry J. Dowsett. Earth system sensitivity inferred from Pliocene modelling and data. Nature Geoscience, 6 December 2009

Cite This Page:

University of Bristol. "Earth more sensitive to carbon dioxide than previously thought." ScienceDaily. ScienceDaily, 7 December 2009. <www.sciencedaily.com/releases/2009/12/091206162955.htm>.
University of Bristol. (2009, December 7). Earth more sensitive to carbon dioxide than previously thought. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2009/12/091206162955.htm
University of Bristol. "Earth more sensitive to carbon dioxide than previously thought." ScienceDaily. www.sciencedaily.com/releases/2009/12/091206162955.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