Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Northern forests less effective than tropical forests in reducing global warming

25.06.2007
Scientists close in on missing carbon sink

Forests in the United States and other northern mid- and upper-latitude regions are playing a smaller role in offsetting global warming than previously thought, according to a study appearing in this week's issue of Science.

The study, which sheds light on the so-called missing carbon sink, concludes that intact tropical forests are removing an unexpectedly high proportion of carbon dioxide from the atmosphere, thereby partially offsetting carbon entering the air through industrial emissions and deforestation.

The Science paper was written by a team of scientists led by Britton Stephens of the National Center for Atmospheric Research (NCAR) in Boulder, Colo. The research was funded by the National Science Foundation (NSF).

"This research fills in another piece of the complex puzzle on how the Earth system functions," said Cliff Jacobs of NSF's Division of Atmospheric Sciences. "These findings will be viewed as a milestone in discoveries about our planet's 'metabolism.'"

Stephens and his colleagues analyzed air samples that had been collected by aircraft across the globe for decades but never before synthesized to study the global carbon cycle. The team found that some 40 percent of the carbon dioxide assumed to be absorbed by northern forests is instead being taken up in the tropics.

"Our study will provide researchers with a much better understanding of how trees and other plants respond to industrial emissions of carbon dioxide, which is a critical problem in global warming," Stephens says. "This will help us better predict climate change and identify possible strategies for mitigating it."

For years, one of the biggest mysteries in climate science has been the question of what ultimately happens to the carbon emitted by motor vehicles, factories, deforestation and other sources.

Of the approximately 8 billion tons of carbon emitted each year, about 40 percent accumulates in the atmosphere and about 30 percent is absorbed by the oceans. Scientists believe that terrestrial ecosystems, especially trees, are taking up the remainder.

Computer models that combine worldwide wind patterns and measurements of carbon dioxide taken just above ground level indicate that northern forests are taking up about 2.4 billion tons. However, ground-based studies have tracked only about half that amount, leaving scientists to speculate about a "missing carbon sink" in the north.

To test whether the computer models were correct, Stephens and his collaborators turned to flasks of air that had been collected by research aircraft over various points of the globe.

The air samples had been collected and analyzed by seven labs, where they were used to investigate various aspects of the carbon cycle, but this is the first time scientists used them to obtain a picture of sources and sinks of carbon on a global level.

The research team compared the air samples to estimates of airborne carbon dioxide concentrations generated by the computer models. They found that the models significantly underestimated the airborne concentrations of carbon dioxide in northern latitudes, especially in the summertime when plants take in more carbon.

The aircraft samples show that northern forests take up only 1.5 billion tons of carbon a year, which is almost 1 billion tons less than the estimate produced by the computer models.

The scientists also found that intact tropical ecosystems are a more important carbon sink than previously thought. The models had generally indicated that tropical ecosystems were a net source of 1.8 billion tons of carbon, largely because trees and other plants release carbon into the atmosphere as a result of widespread logging, burning and other forms of clearing land.

The new research indicates, instead, that tropical ecosystems are the net source of only about 100 million tons, even though tropical deforestation is occurring rapidly.

"Our results indicate that intact tropical forests are taking up a large amount of carbon," Stephens explains. "They are helping to offset industrial carbon emissions and the atmospheric impacts of clearing land more than we realized."

Most of the computers models produced incorrect estimates because, in relying on ground-level measurements, they had failed to accurately simulate the movement of carbon dioxide vertically in the atmosphere.

The computer models tended to move too much carbon dioxide down toward ground level in the summer, when growing trees and other plants take in the gas, and not enough carbon dioxide up from ground level in the winter.

As a result, scientists believed that there was less carbon in the air above mid-latitude and upper-latitude forests, presumably because trees and other plants were absorbing high amounts.

Conversely, scientists had assumed a large amount of carbon was coming out of the tropics and moving through the atmosphere to be taken up in other regions.

The new analysis of aircraft samples shows that this is not the case.

Cheryl Dybas | EurekAlert!
Further information:
http://www.nsf.gov
http://www.nsf.gov/mynsf/

More articles from Ecology, The Environment and Conservation:

nachricht Litter is present throughout the world’s oceans: 1,220 species affected
27.03.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

nachricht International network connects experimental research in European waters
21.03.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

'On-off switch' brings researchers a step closer to potential HIV vaccine

30.03.2017 | Health and Medicine

Penn studies find promise for innovations in liquid biopsies

30.03.2017 | Health and Medicine

An LED-based device for imaging radiation induced skin damage

30.03.2017 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>