Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Tropical Deforestation Affects Rainfall in the U.S. and Around the Globe

13.09.2005


Today, scientists estimate that between one-third and one-half of our planet’s land surfaces have been transformed by human development



Now, a new study is offering insight into the long-term impacts of these changes, particularly the effects of large-scale deforestation in tropical regions on the global climate. Researchers from Duke University, Durham, N.C., analyzed multiple years of data using the NASA Goddard Institute for Space Studies General Circulation Computer Model (GCM) and Global Precipitation Climatology Project (GPCP) to produce several climate simulations. Their research found that deforestation in different areas of the globe affects rainfall patterns over a considerable region.

Deforestation in the Amazon region of South America (Amazonia) influences rainfall from Mexico to Texas and in the Gulf of Mexico. Similarly, deforesting lands in Central Africa affects precipitation in the upper and lower U.S Midwest, while deforestation in Southeast Asia was found to alter rainfall in China and the Balkan Peninsula. It is important to note that such changes primarily occur in certain seasons and that the combination of deforestation in these areas enhances rain in one region while reducing it in another.


This finding contradicts earlier research suggesting deforestation would result in a reduction in precipitation and increase in temperature in the Amazon basin, but carry no detectable impact on the global water cycle.

"Our study carried somewhat surprising results, showing that although the major impact of deforestation on precipitation is found in and near the deforested regions, it also has a strong influence on rainfall in the mid and even high latitudes," said Roni Avissar, lead author of the study, published in the April 2005 issue of the Journal of Hydrometeorology.

Specifically, deforestation of Amazonia was found to severely reduce rainfall in the Gulf of Mexico, Texas, and northern Mexico during the spring and summer seasons when water is crucial for agricultural productivity. Deforestation of Central Africa has a similar effect, causing a significant precipitation decrease in the lower U.S Midwest during the spring and summer and in the upper U.S. Midwest in winter and spring. Deforestation in Southeast Asia alters rainfall in China and the Balkan Peninsula most significantly.

Elimination of any of these tropical forests, Amazonia, Central Africa or Southeast Asia, considerably enhances rainfall in the southern tip of the Arabian Peninsula. However, the combined effect of deforestation in all three regions shifts the greatest precipitation decline in the U.S. to California during the winter season and further increases rainfall in the southern tip of the Arabian Peninsula.

Improved understanding of tropical forested regions is valuable to scientists because of their strong influence on the global climate. The Amazon Basin literally drives weather systems around the world. The tropics receive two-thirds of the world’s rainfall, and when it rains, water changes from liquid to vapor and back again, storing and releasing heat energy in the process. With so much rainfall, an incredible amount of heat is released into the atmosphere - making the tropics the Earth’s primary source of heat redistribution.

"Deforestation does not appear to modify the global average of precipitation, but it changes precipitation patterns and distributions by affecting the amount of both sensible heat and that released into the atmosphere when water vapor condenses, called latent heat," said Avissar. "Associated changes in air pressure distribution shift the typical global circulation patterns, sending storm systems off their typical paths." And, because of the Amazon’s location, any sort of weather hiccup from the area could signal serious changes for the rest of the world like droughts and severe storms.

Clearly, land-cover changes in tropical regions carry potentially significant consequences on water resources, wildfire frequency, agriculture and related activities at various remote locations. And while greenhouse gas emissions and pollutants receive considerable attention, this study shows that land-cover change is another important parameter that needs to be considered in climate policies, especially since deforestation rates in tropical Africa, Southeast Asia, and South America have remained constant or have increased over the past two decades. Land-cover change, depending on its nature, can either mitigate or exacerbate greenhouse warming.

The researchers caution that their results are based on numerical simulations performed with a single general circulation model and that reproducing the experiment with other computer models using different atmospheric variables would be beneficial. Current research is attempting to answer why deforestation has such a major influence on precipitation patterns during respective seasons.

Rob Gutro | EurekAlert!
Further information:
http://www.nasa.gov/centers/goddard/news/topstory/2005/deforest_rainfall.html

More articles from Earth Sciences:

nachricht Turning the Climate Tide by 2020
29.06.2017 | Potsdam-Institut für Klimafolgenforschung

nachricht Predicting eruptions using satellites and math
28.06.2017 | Frontiers

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Making Waves

Computer scientists use wave packet theory to develop realistic, detailed water wave simulations in real time. Their results will be presented at this year’s SIGGRAPH conference.

Think about the last time you were at a lake, river, or the ocean. Remember the ripples of the water, the waves crashing against the rocks, the wake following...

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Nanostructures taste the rainbow

29.06.2017 | Physics and Astronomy

New technique unveils 'matrix' inside tissues and tumors

29.06.2017 | Life Sciences

Cystic fibrosis alters the structure of mucus in airways

29.06.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>