Nav: Home

Greenhouse gas effect caused by mangrove forest conversion is quite significant

April 10, 2017

CORVALLIS, Ore. - Clear-cutting of tropical mangrove forests to create shrimp ponds and cattle pastures contributes significantly to the greenhouse gas effect, one of the leading causes of global warming, new research suggests.

A seven-year study, led by Oregon State University and the Center for International Forestry Research, spanned five countries across the topics from Indonesia to the Dominican Republic. The researchers concluded that mangrove conversion to agricultural uses resulted in a land-use carbon footprint of 1,440 pounds of carbon dioxide released into the atmosphere for the production of every pound of beef; and 1,603 pounds of released carbon dioxide for every pound of shrimp.

"On a personal scale, this means a typical steak and shrimp cocktail dinner produced through mangrove conversion would burden the atmosphere with 1,795 pounds of carbon dioxide," said J. Boone Kauffman, an ecologist at Oregon State University who led the study.

"This is approximately the same amount of greenhouse gases produced by driving a fuel-efficient automobile from Los Angeles to New York City."

The findings are published online today in the journal Frontiers in Ecology and the Environment. The results were derived by the researchers through development of a new measurement - the land-use carbon footprint - by measuring the amount of carbon stored in the intact mangrove forest, the greenhouse gas emissions rising from conversion, and the quantity of the shrimp or beef produced over the life of the land use.

Mangroves represent 0.6 percent of all the world's tropical forests but their deforestation accounts for as much as 12 percent of greenhouse gas emissions that come from all tropical deforestation, Kauffman said.

"What we found was astounding," said Kauffman, a senior research professor in the College of Agricultural Sciences. "It's a remarkable amount of carbon that is emitted into the atmosphere when you convert these mangrove forests to shrimp ponds or pastures. And the food productivity of these sites is not really very high."

Mangroves are a group of trees and shrubs that live in tropical coastal intertidal zones. There are about 80 different species of mangrove trees. All of these trees grow in areas of waterlogged soils, where slow-moving waters allow fine sediments to accumulate. In these environments, mangroves sequester significant quantities of carbon that is stored for centuries.

Rates of deforestation of mangroves have been dramatic over the past three decades. They are disappearing at the rate of about 1 percent per year. Conversion to shrimp ponds is the greatest single cause of mangrove degradation and decline in Southeast Asia.

The study was conducted on 30 relatively undisturbed mangrove forests and 21 adjacent shrimp ponds or cattle pastures. The sites were in Costa Rica, the Dominican Republic, Honduras, Indonesia and Mexico. Shrimp ponds were sampled in all countries except Mexico, where the predominant land use was conversion to cattle pastures.

The decline in carbon storage from mangrove conversion to shrimp ponds or cattle pastures exceeded the research group's previous estimates.

"These forests have been absorbing carbon for the last 4,000 or 5,000 years and now through deforestation they have become significant sources of greenhouse gas emissions," Kauffman said. "Because they store so much carbon that is released as greenhouse gases when deforested they are important sites for protection in order to mitigate or slow climate change."
-end-
Collaborators on the study were researchers at Counterpart International in Arlington, Virginia; Universidade Juarez Autonoma de Tabasco Villhermosa in Mexico; the Tropical Agricultural Research and Higher Education Center in Costa Rica; the Center for Climate Change Studies at the University of Mulawarman in Indonesia; Bogor Agricultural University in Indonesia; and the Center for International Forest Research in Indonesia.

Funding for the study was provided by the U.S. Agency for International Development, the Council for Economic Development and Counterpart International.

Oregon State University

Related Global Warming Articles:

A new study provides a solid evidence for global warming
The new study allows a more accurate assessment of how much heat has accumulated in the ocean (and Earth) system.
Global warming hiatus disproved -- again
UC Berkeley scientists calculated average ocean temperatures from 1999 to 2015, separately using ocean buoys and satellite data, and confirmed the uninterrupted warming trend reported by NOAA in 2015, based on that organization's recalibration of sea surface temperature recordings from ships and buoys.
Report reassesses variations in global warming
Experts at the European Centre for Medium-Range Weather Forecasts (ECMWF) have issued a new assessment of temperature trends and variations from the latest available data and analyses.
Clouds are impeding global warming... for now
Lawrence Livermore National Laboratory researchers have identified a mechanism that causes low clouds -- and their influence on Earth's energy balance -- to respond differently to global warming depending on their spatial pattern.
Global warming's next surprise: Saltier beaches
Batches of sand from a beach on the Delaware Bay are yielding insights into the powerful impact of temperature rise and evaporation along the shore that are in turn challenging long-held assumptions about what causes beach salinity to fluctuate in coastal zones that support a rich network of sea creatures and plants.
Could global warming's top culprit help crops?
A new study tries to disentangle the complex question of whether rising amounts of carbon dioxide in the air might in some cases help crops.
Evaporation for review -- and with it global warming
The process of evaporation, one of the most widespread on our planet, takes place differently than we once thought -- this has been shown by new computer simulations carried out at the Institute of Physical Chemistry of the Polish Academy of Sciences in Warsaw.
Researchers reveal when global warming first appeared
Human caused climate change is increasingly apparent today through multiple lines of evidence.
1,800 years of global ocean cooling halted by global warming
Prior to the advent of human-caused global warming in the 19th century, the surface layer of Earth's oceans had undergone 1,800 years of a steady cooling trend, according to a new study in the Aug.
Global sea levels have risen 6 meters or more with just slight global warming
A new review analyzing three decades of research on the historic effects of melting polar ice sheets found that global sea levels have risen at least six meters, or about 20 feet, above present levels on multiple occasions over the past three million years.

Related Global Warming Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Digital Manipulation
Technology has reshaped our lives in amazing ways. But at what cost? This hour, TED speakers reveal how what we see, read, believe — even how we vote — can be manipulated by the technology we use. Guests include journalist Carole Cadwalladr, consumer advocate Finn Myrstad, writer and marketing professor Scott Galloway, behavioral designer Nir Eyal, and computer graphics researcher Doug Roble.
Now Playing: Science for the People

#530 Why Aren't We Dead Yet?
We only notice our immune systems when they aren't working properly, or when they're under attack. How does our immune system understand what bits of us are us, and what bits are invading germs and viruses? How different are human immune systems from the immune systems of other creatures? And is the immune system so often the target of sketchy medical advice? Those questions and more, this week in our conversation with author Idan Ben-Barak about his book "Why Aren't We Dead Yet?: The Survivor’s Guide to the Immune System".