Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Deforestation reduces rainfall in West African forests

19.09.2011
Cutting down forests to create cropland in the West African rainforest reduces precipitation over the rest of the forest, according to new research.

The study shows that West African rainforest deforestation reduces precipitation over neighboring trees by about 50 percent due to increased surface temperatures of croplands, which affect raincloud formation.

The authors say the findings have important implications for future decisions about land management in this region and other rainforests, including the Amazon.

"We already know from satellite observations that changes in land use can have a big impact on local weather patterns," says Luis Garcia-Carreras with the University of Leeds School of Earth and Environment, lead author of the recent study. "Here we have been able to show why this happens."

"Our findings suggest that it's not just the number of trees removed that threatens the stability of the world's rainforests. The pattern of deforestation is also important."

Garcia-Carreras and his colleague present their new findings in an article accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union.

The forests of West Africa and the Congo Basin are the second largest in the world after the Amazon rainforest. They serve not only as a habitat for a vast and diverse ecosystem but also as a carbon sink, removing a large proportion of the carbon dioxide in the Earth's atmosphere and slowing down climate change.

For many years deforestation has been occurring widely in Africa, with tree canopies being removed for agriculture, plantations and other non-forest uses.

While the removal of trees has an immediate impact on the forest, this new study suggests that there also may be a secondary effect caused by the reduced rainfall.

"African rainforests already have the lowest rainfall of any rainforest ecosystem on Earth, which could make them particularly sensitive to changes in local weather patterns," Garcia-Carreras says. "If rainfall is reduced even further as a result of deforestation, it could threaten the survival of the remaining forest by increasing the trees' sensitivity to drought."

To investigate the effects of different vegetation on locally-produced rain in West Africa, the researchers used a Met Office computer model to simulate rainfall under different land-use conditions.

In rainforests where stands had been converted to cropland, the total amount of precipitation was largely unaffected, but the rainfall was distributed differently.

Rainfall was four to six times higher over warm areas (cropland) than when no deforestation has occurred, while rainfall over the remaining forest was half or less.

The difference in rainfall is caused by the temperature change between cropland and forest, which produces winds that converge over the crop area and form clouds.

And the results in West Africa could apply elsewhere, adds Doug Parker, a study co- author with the University of Leeds. "While our study only focused on a small region in Africa, it's reasonable to suggest that this mechanism could be common in other global forests based on similar observations of rainfall in Amazonia," he says.

"This has implications for planners in terms of how deforestation is managed. If forest must be removed to create cropland, we need to think about what are the shapes and distributions of deforestation that will be least damaging to the adjacent forests and national parks."

The research was funded by the UK's Natural Environment Research Council as part of the international African Monsoon Multidisciplinary Analysis (AMMA).

Title:
"How Does Local Tropical Deforestation Affect Rainfall?"
Authors:
Luis Garcia-Carreras and Douglas J. Parker: Institute for Climate and Atmospheric Science, University of Leeds, Leeds, United Kingdom.
Contact information for the authors:
Luis Garcia-Carreras, Leeds research fellow: +44 113 3434931, L.Garcia- Carreras@leeds.ac.uk

Kate Ramsayer | American Geophysical Union
Further information:
http://www.agu.org

More articles from Earth Sciences:

nachricht What makes corals sick?
11.12.2017 | Leibniz-Zentrum für Marine Tropenforschung (ZMT)

nachricht Mars’ atmosphere well protected from the solar wind
08.12.2017 | Schwedischer Forschungsrat - The Swedish Research Council

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

Im Focus: Virtual Reality for Bacteria

An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications

Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...

Im Focus: A space-time sensor for light-matter interactions

Physicists in the Laboratory for Attosecond Physics (run jointly by LMU Munich and the Max Planck Institute for Quantum Optics) have developed an attosecond electron microscope that allows them to visualize the dispersion of light in time and space, and observe the motions of electrons in atoms.

The most basic of all physical interactions in nature is that between light and matter. This interaction takes place in attosecond times (i.e. billionths of a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

Blockchain is becoming more important in the energy market

05.12.2017 | Event News

 
Latest News

New research identifies how 3-D printed metals can be both strong and ductile

11.12.2017 | Physics and Astronomy

Scientists channel graphene to understand filtration and ion transport into cells

11.12.2017 | Materials Sciences

What makes corals sick?

11.12.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>