Printer Friendly

Termites not to blame for methane.

Termites not to blame for methane

As concern builds over the threat of global warming, scientists are trying to understand why atmospheric levels of methane, a greenhouse gas, have more than doubled in the last two centuries. Researchers in the early 1980s suggested termites may deserve partial blame for the increase, but a comprehensive study downplays their role.

"Although the uncertainties are still very large, the weight of the scientific evidence is shifting toward the conclusion that termites are not an important global sources of methane," report M. Aslam K. Khalil and R.A. Rasmussen at the Oregon Graduate Center in Beaverton along wth Australian colleagues. They describe their work in the March 20 JOURNAL OF GEOPHYSICAL RESEARCH.

The researchers measured gases emitted by six termite species in Australia and reviewed the published data concerning how much food termites consume. They estimate termites worldwide emit about 12 X [10.sup.12] grams per year of methane, which amounts to about 2 percent of the methane released by all global sources each year. This number agrees with results from lab measurements and a field study in Africa.

In 1982, researchers from the National Center for Atmospheric Research in Boulder, Colo., sparked the debate over termites when they reported estiamtes based on laboratory work that termites emit 150 X [10.sup.12] grams each year, which would constitute about 30 percent of the world's annual methane emissions. They also suggested that human activities such as deforestation have boosted termite populations, which could explain part of the rise in methane concentrations.

Khalil says the earlier study overestimated the amount of food consumed by termites each year and did not take into account methane absorption by the ground near their mounds, a fact discovered only during field experiments. According to Khalil, the methane buildup in the atmosphere stems not from a population explosion in termites but from increasing numbers of rice fields, cattle and sheep.
COPYRIGHT 1990 Science Service, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1990, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

 Reader Opinion

Title:

Comment:



 

Article Details
Printer friendly Cite/link Email Feedback
Publication:Science News
Date:Apr 28, 1990
Words:321
Previous Article:Cancer-fighting cell receptor cloned.
Next Article:Cuba proposed site for K/T impact.
Topics:


Related Articles
Are landfills a major threat to climate?
Soil nitrogen leaves methane up in the air.
Wetlands provide clue to greenhouse gas.
CO2 increase boosts methane emissions.
Caribbean blasts sparked global warmth.
Global warming culprit: greenhouse gases.
Tree-Eating Termites Hit South.
No Tenting Tonight.
Does my gas cause global warming? Belches and flatulence are harmless, right? Wrong! When cattle and sheep burp and pass gas, the entire planet...
Munching along: warning: aggressive alien termites could be headed your way.

Terms of use | Copyright © 2014 Farlex, Inc. | Feedback | For webmasters