Featured Research

from universities, journals, and other organizations

Carbon dioxide controls Earth's temperature, new modeling study shows

Date:
October 15, 2010
Source:
NASA/Goddard Space Flight Center
Summary:
Water vapor and clouds are the major contributors to Earth's greenhouse effect, but a new atmosphere-ocean climate modeling study shows that the planet's temperature ultimately depends on the atmospheric level of carbon dioxide.

Various atmospheric components differ in their contributions to the greenhouse effect, some through feedbacks and some through forcings. Without carbon dioxide and other non-condensing greenhouse gases, water vapor and clouds would be unable to provide the feedback mechanisms that amplify the greenhouse effect.
Credit: NASA GISS

Water vapor and clouds are the major contributors to Earth's greenhouse effect, but a new atmosphere-ocean climate modeling study shows that the planet's temperature ultimately depends on the atmospheric level of carbon dioxide.

The study, conducted by Andrew Lacis and colleagues at NASA's Goddard Institute for Space Studies (GISS) in New York, examined the nature of Earth's greenhouse effect and clarified the role that greenhouse gases and clouds play in absorbing outgoing infrared radiation. Notably, the team identified non-condensing greenhouse gases -- such as carbon dioxide, methane, nitrous oxide, ozone, and chlorofluorocarbons -- as providing the core support for the terrestrial greenhouse effect.

Without non-condensing greenhouse gases, water vapor and clouds would be unable to provide the feedback mechanisms that amplify the greenhouse effect. The study's results are published Oct. 15 in Science.

A companion study led by GISS co-author Gavin Schmidt that has been accepted for publication in the Journal of Geophysical Research shows that carbon dioxide accounts for about 20 percent of the greenhouse effect, water vapor and clouds together account for 75 percent, and minor gases and aerosols make up the remaining five percent. However, it is the 25 percent non-condensing greenhouse gas component, which includes carbon dioxide, that is the key factor in sustaining Earth's greenhouse effect. By this accounting, carbon dioxide is responsible for 80 percent of the radiative forcing that sustains the Earth's greenhouse effect.

The climate forcing experiment described in Science was simple in design and concept -- all of the non-condensing greenhouse gases and aerosols were zeroed out, and the global climate model was run forward in time to see what would happen to the greenhouse effect.

Without the sustaining support by the non-condensing greenhouse gases, Earth's greenhouse effect collapsed as water vapor quickly precipitated from the atmosphere, plunging the model Earth into an icebound state -- a clear demonstration that water vapor, although contributing 50 percent of the total greenhouse warming, acts as a feedback process, and as such, cannot by itself uphold the Earth's greenhouse effect.

"Our climate modeling simulation should be viewed as an experiment in atmospheric physics, illustrating a cause and effect problem which allowed us to gain a better understanding of the working mechanics of Earth's greenhouse effect, and enabled us to demonstrate the direct relationship that exists between rising atmospheric carbon dioxide and rising global temperature," Lacis said.

The study ties in to the geologic record in which carbon dioxide levels have oscillated between approximately 180 parts per million during ice ages, and about 280 parts per million during warmer interglacial periods. To provide perspective to the nearly 1 C (1.8 F) increase in global temperature over the past century, it is estimated that the global mean temperature difference between the extremes of the ice age and interglacial periods is only about 5 C (9 F).

"When carbon dioxide increases, more water vapor returns to the atmosphere. This is what helped to melt the glaciers that once covered New York City," said co-author David Rind, of NASA's Goddard Institute for Space Studies. "Today we are in uncharted territory as carbon dioxide approaches 390 parts per million in what has been referred to as the 'superinterglacial.'"

"The bottom line is that atmospheric carbon dioxide acts as a thermostat in regulating the temperature of Earth," Lacis said. "The Intergovernmental Panel on Climate Change has fully documented the fact that industrial activity is responsible for the rapidly increasing levels of atmospheric carbon dioxide and other greenhouse gases. It is not surprising then that global warming can be linked directly to the observed increase in atmospheric carbon dioxide and to human industrial activity in general."


Story Source:

The above story is based on materials provided by NASA/Goddard Space Flight Center. The original article was written by Kathryn Hansen, NASA's Earth Science News Team. Note: Materials may be edited for content and length.


Journal Reference:

  1. A. A. Lacis, G. A. Schmidt, D. Rind, R. A. Ruedy. Atmospheric CO2: Principal Control Knob Governing Earth's Temperature. Science, 2010; 330 (6002): 356 DOI: 10.1126/science.1190653

Cite This Page:

NASA/Goddard Space Flight Center. "Carbon dioxide controls Earth's temperature, new modeling study shows." ScienceDaily. ScienceDaily, 15 October 2010. <www.sciencedaily.com/releases/2010/10/101014171146.htm>.
NASA/Goddard Space Flight Center. (2010, October 15). Carbon dioxide controls Earth's temperature, new modeling study shows. ScienceDaily. Retrieved September 30, 2014 from www.sciencedaily.com/releases/2010/10/101014171146.htm
NASA/Goddard Space Flight Center. "Carbon dioxide controls Earth's temperature, new modeling study shows." ScienceDaily. www.sciencedaily.com/releases/2010/10/101014171146.htm (accessed September 30, 2014).

Share This



More Earth & Climate News

Tuesday, September 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Balloon Descends to Bottom of Croatian Cave

Raw: Balloon Descends to Bottom of Croatian Cave

AP (Sep. 29, 2014) An Austrian balloon pilot has succeeded in taking a balloon deep underground, a feat which he believes is a world first. (Sept. 29) Video provided by AP
Powered by NewsLook.com
Bodies Recovered from Japan Volcano Eruption

Bodies Recovered from Japan Volcano Eruption

AP (Sep. 29, 2014) Rescue crews finished recovering the remaining 27 bodies from atop Japan's Mount Ontake Monday. At least 31 people were killed Saturday in the mountain's first fatal volcanic event in modern history. (Sept. 29) Video provided by AP
Powered by NewsLook.com
Raw: Japan's Mount Ontake Erupts

Raw: Japan's Mount Ontake Erupts

AP (Sep. 27, 2014) A volcano erupted in central Japan on Saturday, sending a large plume of ash high into the sky and prompting a warning to climbers and others to avoid the area. (Sept. 27) Video provided by AP
Powered by NewsLook.com
California University Designs Sustainable Winery

California University Designs Sustainable Winery

Reuters - US Online Video (Sep. 27, 2014) Amid California's worst drought in decades, scientists at UC Davis design a sustainable winery that includes a water recycling system. Vanessa Johnston 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