Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Tropical deforestation and global warming

14.02.2003


Smithsonian scientist challenges results of recent study



Late last year, Frédéric Achard and colleagues published a controversial article in which they contended that earlier estimates of worldwide tropical deforestation and atmospheric carbon emissions were too high. In the February 14 issue of Science, Philip Fearnside from the National Institute for Amazonian Research in Brazil, and William Laurance from the Smithsonian Tropical Research Institute in Panama argue that the Achard study contains serious flaws rendering its conclusions about greenhouse gases unreliable.
The article in question ("Determination of deforestation rates of the world’s humid tropical forests", Science, vol. 297, pages 999-1002), which received extensive press coverage, asserted that only about 0.6 to 1.0 billion tons of greenhouse gases (most carbon dioxide and carbon monoxide) were being produced by the razing and felling of tropical forests each year. This estimate is considerably lower than those of earlier studies, which estimated up to 2.4 billion tons annually.

Fearnside and Laurance list seven serious errors or limitations of the Achard study, which, they say, collectively lead to a major underestimate of greenhouse gas emissions.



Among the errors they identify is that the Achard team failed to include drier tropical forests--which are also being rapidly cleared and burned--in their estimate. Other concerns include underestimating the amount of biomass--and hence the amount of carbon--contained in tropical forests. The study assumes that regenerating forests on abandoned lands will re-absorb large amounts of atmospheric carbon. In fact, such forests are often re-cleared after a few years. The study also fails to consider the effects of important greenhouse gases like methane and nitrous oxide, which are also produced by deforestation.

Fearnside and Laurance further assert that the effects on global warming of selective logging, habitat fragmentation, and other types of forest degradation are not included in the Achard study. Selective logging, for example, does not cause deforestation per se but produces hundreds of millions of tons of greenhouse gas emissions each year.

"When you look at all these factors, you can’t help but conclude that their numbers are too small," said Laurance. "They’re suggesting that tropical deforestation and degradation accounts for only about a tenth of the global production of greenhouse gases. Personally, I’d argue that their estimate is two to three times too low."

Each year, humans produce seven to eight billion tons of greenhouse gas emissions, which are considered the major cause of global warming. Most emissions are produced by the burning of fossil fuels and tropical deforestation, but the relative importance of these two sources remains controversial.



For further information:
William F. Laurance
Smithsonian Tropical Research Institute
Balboa, Panama
Phone: 507-314-9206 and 507-212-8252
Email: laurancew@tivoli.si.edu

Philip M. Fearnside
National Institute for Amazonian Research
Manaus, Brazil
Phone: 55-92-642-8913 and 55-92-643-1822
Email: pmfearn@inpa.gov.br

Researchers at the Smithsonian Tropical Research Institute, with headquarters in Panama City, Panama, study the past, present and future of tropical biodiversity and its implications for humankind.

Dr. Bill Laurance | EurekAlert!
Further information:
http://www.si.edu/

More articles from Ecology, The Environment and Conservation:

nachricht Upcycling 'fast fashion' to reduce waste and pollution
03.04.2017 | American Chemical Society

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

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: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

NASA's Fermi catches gamma-ray flashes from tropical storms

25.04.2017 | Physics and Astronomy

Researchers invent process to make sustainable rubber, plastics

25.04.2017 | Materials Sciences

Transfecting cells gently – the LZH presents a GNOME prototype at the Labvolution 2017

25.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>