Forests damaged by Katrina may contribute to global warming

November 15, 2007

Researchers led by biologist Jeffrey Chambers of Tulane University have determined that the losses inflicted by Hurricane Katrina on Gulf Coast forest trees are enough to cancel out a year's worth of new tree biomass (trunks, branches and foliage) growth in other parts of the country.

"The carbon that will be released as these trees decompose is enough to cancel out an entire year's worth of net gain by all U.S. forests. And this is only from a single storm," says Chambers, lead author of an article detailing the team's findings, "Hurricane Katrina's Carbon Footprint on Gulf Coast Forests," published in the Nov. 16 issue of the journal Science.

The study was carried out by researchers at Tulane and the University of New Hampshire. Using NASA satellite sensing technology, ecological field investigations and statistical analysis, the investigators estimate that 320 million large trees were killed or severely damaged by the August 2005 storm.

As the Earth's climate warms, evidence is accumulating that hurricanes, tornados and frontal systems will gain in energy, producing more violent storms and stronger winds. Increased wind disturbance will cause more tree mortality and damage, and this dead wood will release additional carbon to the atmosphere, potentially amplifying global warming.

Young, healthy forests play a vital role in removing carbon, in the form of carbon dioxide, a greenhouse gas, from the atmosphere by photosynthesis, and are thus important in the battle against warming. These young forests are valued as "carbon sinks," removing carbon dioxide from the atmosphere and storing it as growing vegetation.

The total amount of carbon stored in a forest is the result of the growth of new and existing trees, and tree death from age and disturbance. Dead trees and downed wood decompose and release carbon to the atmosphere. Thus, an increase in disturbance frequency, for example from more powerful storms, can tilt this balance toward the loss side, reversing the storing process and becoming a source of atmospheric carbon dioxide.

This increase in carbon emissions can enhance global warming in what is termed by scientists a "positive feedback mechanism." Increased carbon dioxide warms the climate, causing more intense storms and elevated tree mortality, releasing yet more carbon dioxide and further warming the climate.
-end-
The study was funded by the U.S. Department of Energy's National Institute of Climatic Change Research. NASA provided satellite data for the study and many of the methods used were first developed as part of a NASA Large Scale Biosphere-Atmosphere Experiment in Amazonia, led by Chambers.

Tulane University

Related Greenhouse Gas Articles from Brightsurf:

Make your own greenhouse gas logger
Researchers at Linköping University's Department of Thematic Studies, Environmental Change, have developed a simple logger for greenhouse gas flows.

Old carbon reservoirs unlikely to cause massive greenhouse gas release
As global temperatures rise, permafrost and methane hydrates -- large reservoirs of ancient carbon -- have the potential to break down, releasing enormous quantities of the potent greenhouse gas methane.

Mediterranean rainfall immediately affected by greenhouse gas changes
Mediterranean-type climates face immediate drops in rainfall when greenhouse gases rise, but this could be interrupted quickly if emissions are cut.

Seeking better guidelines for inventorying greenhouse gas emissions
Governments around the world are striving to hit reduction targets using Intergovernmental Panel on Climate Change (IPCC) guidelines to limit global warming.

Nitrous oxide, a greenhouse gas, is on the rise
A new study from an international group of scientists finds we are releasing more of the greenhouse gas nitrous oxide into the atmosphere than previously thought.

Atmospheric pressure impacts greenhouse gas emissions from leaky oil and gas wells
Fluctuations in atmospheric pressure can heavily influence how much natural gas leaks from wells below the ground surface at oil and gas sites, according to new University of British Columbia research.

Natural-gas leaks are important source of greenhouse gas emissions in Los Angeles
Liyin He, a Caltech graduate student, finds that methane in L.A.'s air correlates with the seasonal use of gas for heating homes and businesses

From greenhouse gas to fuel
University of Delaware scientists are part of an international team of researchers that has revealed a new approach to convert carbon dioxide gas into valuable chemicals and fuels.

UBC researchers explore an often ignored source of greenhouse gas
In a new study from UBC's Okanagan campus, researchers have discovered a surprising new source of carbon dioxide (CO2) emissions -- bicarbonates hidden in the lake water used to irrigate local orchards.

Corncob ethanol may help cut China's greenhouse gas emissions
A new Biofuels, Bioproducts and Biorefining study has found that using ethanol from corncobs for energy production may help reduce greenhouse gas emissions in China, if used instead of starch-based ethanol.

Read More: Greenhouse Gas News and Greenhouse Gas Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.