Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Fires in far northern forests to have cooling, not warming, effect

20.11.2006
Droughts and longer summers tied to global warming are causing more fires in the Earth's vast northernmost forests, a phenomenon that will spew a steadily increasing amount of carbon dioxide into the atmosphere.

Many scientists have predicted that the result of this influx of greenhouse gas will be even more warming, followed by even more fires and so on – a vicious climactic cycle.

But a team of scientists, including two University of Florida ecologists, has arrived at just the opposite conclusion. Their research shows that while the carbon released by burning high-latitude forests of North America, Europe and Russia will no doubt have a warming effect, it will be less than an unexpected cooling effect. That will come from millions of new deciduous trees reflecting the sun's light away from Earth with their light green leaves in the summer. In the winter, these trees lose their leaves, and white snow on the ground will reflect even more light.

A paper about the research is set to appear Friday in the journal Science.

"The reflectivity effect in the long run is larger than the carbon effect," said Michelle Mack, a co-author and a UF assistant professor of ecology in the botany department.

The research is of broad interest because it calls for a re-examination of strategies to reduce carbon dioxide emissions through human-wrought changes to ecosystems, such as forest management and tree plantations. These strategies have been widely discussed since the 1990s. The study doesn't suggest that such so-called "carbon sequestration" plans will never work. Indeed, reducing atmospheric carbon is generally a good idea, say Mack and Ted Schuur, a UF assistant professor of ecology in the botany department and a co-author.

Rather, the study implies that scientists need to look at the entire chain of events in a plan to manage climate effects using ecosystems before concluding how the plan will contribute to, or offset, a warming effect.

"What we're showing," Schuur said, "is that if you are going to manage an ecosystem to have an effect on the climate via carbon sequestration, you need to consider all the other climate forcing factors you may be changing at the same time."

Northern, or boreal, forests occupy 5.7 million square miles, or 14.5 percent, of the earth's land surface. They store 30 percent of Earth's "carbon pool" in plants and soils.

Scientists agree that the effects of global warming are most severe nearest the poles, and boreal forests are already facing longer summers and more prolonged dry periods. This has spurred many large fires, with the most massive forest fires in recorded Alaskan history occurring in the summer 2004.

While carbon emissions from these fires have long been thought to contribute to global warming, the UF and other researchers decided to look at other associated climate effects of fires. They focused on both the single year after an Alaska fire and for an 80-year period during which plants and trees would re-grow over the burnt landscape.

Seventeen researchers from at least nine universities and research institutes conducted a wide range of investigations for the study, which examined the site of the 1999 Donnelly Flats crown fire, a fire that burned about 18,780 acres in Alaska's interior.

At UF, Mack measured the amount of carbon released in the burning of black spruce, the most common tree species in North American boreal forest, and the re-growth of new vegetation. Schuur studied the exchange of carbon dioxide between boreal soils and the atmosphere. Other scientists examined the so-called "albedo," or amount of light reflected from spruce, burned soils and broad-leaved trees.

The scientists plugged their field observations and satellite data into computer models, which extended the results eight decades. The first year following fire was warmer, due in part to added carbon, aerosol and ozone from burning, the researchers found. But the models came to the opposite conclusion relatively quickly, within 10 to 15 years.

The main reason was that the first trees to replace the burnt conifers were aspen, birch and other deciduous trees, with large light-green leaves. These leaves reflected more of the sun's energy than did the dark green, thin-needled black spruce, and as a result, less of the incoming energy went into heating the ecosystem. Even more important, in the winter the birches and other deciduous trees lose their leaves – revealing even more reflective (white snow. The black spruce would eventually grow back, but it will take a long time to dominate the deciduous trees and reduce the reflected light, the researchers said.

Ted Schuur | EurekAlert!
Further information:
http://www.ufl.edu

More articles from Ecology, The Environment and Conservation:

nachricht Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel

nachricht Removing fossil fuel subsidies will not reduce CO2 emissions as much as hoped
08.02.2018 | International Institute for Applied Systems Analysis (IIASA)

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: Attoseconds break into atomic interior

A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.

In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...

Im Focus: Good vibrations feel the force

A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.

By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...

Im Focus: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Basque researchers turn light upside down

23.02.2018 | Physics and Astronomy

Finnish research group discovers a new immune system regulator

23.02.2018 | Health and Medicine

Attoseconds break into atomic interior

23.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>