Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Growth in Amazon cropland may impact climate and deforestation patterns

21.09.2006
Scientists using NASA satellite data have found that clearing for mechanized cropland has recently become a significant force in Brazilian Amazon deforestation. This change in land use may alter the region's climate and the land's ability to absorb carbon dioxide.

A study published online in the September 14, 2006 edition of the Proceedings of the National Academy of Sciences examined cropland expansion in Mato Grosso, the Brazilian state with the highest deforestation and soybean production rates. Using data from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra and Aqua satellites and information from field observations, researchers found that in 2003, the peak year of deforestation, more than 20 percent of the state's forests were converted to cropland. This finding suggests that the recent cropland expansion in the region is contributing to further deforestation.

The high resolution and daily frequency of MODIS images allows researchers to distinguish vegetation types in greater detail than other satellites. This capability has helped the scientists to see for the first time that the size of the clearings used for crops has averaged twice the size of clearings used for pasture. Land conversion has also occurred rapidly, with about 90 percent of new crops planted within a year of deforestation.

"Deforestation for cropland usually involves clearing several square kilometers of land and results in greater separation of remnant patches of forest than other types of land use," said study lead author Douglas Morton, University of Maryland, College Park, Md. "MODIS data is especially helpful in monitoring these changes because its two daytime observations provide much better data than other satellites over typically cloudy regions like the Amazon basin to help distinguish different land cover types."

In addition to mapping the change in land use type over Mato Grosso between 2001 and 2004, the researchers compared these changes with shifts in agricultural prices in the region. The study found a strong correlation between the amount of land deforested and the average annual soybean price. As soybean prices rose in 2003, the conversion from forest to cropland increased, while the amount of land converted to pasture declined.

"In 2005, soybean prices fell by more than 25 percent and some areas of Mato Grosso showed a decrease in large deforestation events, although the central agricultural zone continued to clear forests," said Morton. "But, deforestation rates could return to the high levels seen in 2003 as soybean and other crop prices begin to rebound in international markets." Brazil has become a leading worldwide producer of grains including soybean, accounting for more than one-third of the country's gross national product. This new driver of forest loss suggests that the rise and fall of prices for other crops, beef and timber may also have a significant impact on future land use in the region, according to the study.

Converting forests to cropland also has a more pronounced ecological and climate impact than other land conversions because it involves the complete removal of land biomass, including tree trunks, stumps and woody roots. "The carbon once contained in the living material and soil is released into the air from multiple fires during the clearing process, causing atmospheric carbon dioxide concentrations, a primary greenhouse gas, to increase," said co-author Ruth DeFries, University of Maryland. Of all land uses and types, croplands are also one of the least efficient at absorbing carbon from the air.

In a related study, to be published in Earth Interactions, researchers found that the region's climate is impacted not only by the overall extent of clearing, but also by the type of subsequent land use. Changes in land cover and use directly influence climate by affecting the amount of solar energy absorbed at the surface, the transfer and flow of heat, and the transport of water from the land and plants through evaporation, a cooling process.

Using a computer climate model driven by MODIS data, the researchers examined the sensitivities of climate to recent changes in Mato Grosso. Model results indicate that areas converted from tropical forest to cropland, including soybean, result in warmer, drier conditions. But the conversion of forest into pasture -- land with grasses -- results in a cooling effect.

Tropical forests generally keep temperatures cooler because they transpire water through their leaves and roots. As a result, forests can maintain the regional climate more readily than croplands, even during the dry season.

"We found areas deforested and left with bare ground had the most profound impact on climate, raising temperatures up to 3 degrees Fahrenheit," said study co-author Lahouari Bounoua, NASA Goddard Space Flight Center, Greenbelt, Md. "Forests replaced with croplands had the second most significant climate impact, followed next by pastures."

These findings suggest that recent land conversions of the Amazon forest may have measurable effects on the regional climate.

It is important for scientists to understand climate change in the region because the tropics receive two-thirds of the world's rainfall. When it rains, water changes from liquid to vapor and back again, storing and releasing heat in the process. With so much rainfall, a large amount of heat is released into the atmosphere -- fueling large-scale atmospheric circulations that transport heat and influence weather patterns both regionally and globally.

Deforestation remains Brazil's largest source of carbon dioxide emissions. These studies identify the evolution of individual land clearings over time to help grasp the fate of land use following deforestation. "This research provides the information needed for programs to reduce deforestation, projections of future deforestation, and efforts to identify priority areas for conservation," said Morton.

Both research studies were supported by the Large Scale Biosphere-Atmosphere Experiment in the Amazon, an international research effort led by the Brazilian Ministry of Science and Technology and sponsored by NASA's Terrestrial Ecology and Land Use-Land Cover Change Programs. The project aims to understand how Amazonia functions as a regional entity within the larger Earth system, and how changes in land use and climate will affect the biological, physical, and chemical functioning of the region's ecosystem.

Rob Gutro | EurekAlert!
Further information:
http://www.nasa.gov
http://www.nasa.gov/centers/goddard/news/topstory/2006/amazon_crops.html

More articles from Ecology, The Environment and Conservation:

nachricht Joint research project on wastewater for reuse examines pond system in Namibia
19.12.2016 | Technische Universität Darmstadt

nachricht Scientists produce a new roadmap for guiding development & conservation in the Amazon
09.12.2016 | Wildlife Conservation Society

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

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

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

17.01.2017 | Materials Sciences

Smart homes will “LISTEN” to your voice

17.01.2017 | Architecture and Construction

VideoLinks
B2B-VideoLinks
More VideoLinks >>>