Tuesday 10 april 2012 2 10 /04 /Abr /2012 22:18

.

Between May 2000 and August 2005, Brazil lost more than 132,000 km2 of forest—an area larger than Greece—and since 1970, over 600,000 km2 of Amazon rainforest have been destroyed. Why is Brazil losing so much forest? What can be done to slow deforestation?

Alertan sobre el impacto de la deforestación

Para especialista del Programa de las Naciones Unidas para el Desarrollo, la tala de bosques contribuye con hasta el 20 por ciento de la emisión de gases de efecto invernadero que aumentan la temperatura del planeta.

(Agencia CyTA-Instituto Leloir. Bruno Geller)-. Las tasas de deforestación a nivel mundial contribuyen con el 15 al 20 por ciento de las emisiones globales de gases con efecto invernadero, lo que tiene un impacto directo tanto sobre el cambio climático como en la reducción de la biodiversidad. Así lo señaló a la Agencia CyTA la economista Emma Torres, asesora principal de medio ambiente y energía de la dirección regional de America Latina y el Caribe del Programa de las Naciones Unidas para el Desarrollo (PNUD).

Según la especialista, el fenómeno responde a varios factores. “Por ejemplo, en lo que respecta al bosque tropical amazónico, la deforestación está asociada en gran medida con la expansión de la frontera agrícola y ganadera, con la construcción de carreteras, la extracción ilegal de madera, la exploración minera y petrolera y la expansión de plantas hidroeléctricas”, puntualizó Torres, para quien merece destacarse el gran esfuerzo realizado por Brasil para reducir las talas en el Amazonas  en más de 70 por ciento durante seis años consecutivos.

Si bien existen registros de plantas terrestres de hace 420 millones de años y 35 millones de años después aparecieron los grandes árboles que protegieran de irradiación el suelo con sus copas, recién se han conocido bosques similares a los que podemos ver en los últimos 60 millones de años, destacó a la Agencia CyTA el doctor Ari Iglesias, investigador del CONICET en la División Paleobotánica del Museo de Ciencias Naturales de la Universidad de La Plata.

Los bosques proporcionan numerosos y singulares beneficios a la humanidad: proveen madera, purifican el agua, absorben CO2, fertilizan la tierra  y ayudan distribución de semillas y control de plagas, entre otras funciones.

“Los bosques desempeñan un papel similar al de una gran industria de servicios públicos”, afirmó Torres, quien agregó que se estima que los bosques ancestrales tropicales absorben unos 4,4 mil millones de toneladas de CO2 por año o el equivalente al 15 por ciento de emisiones anuales de gases con efecto invernadero. “Por tanto, la tala de árboles no solo genera emisiones de CO2 sino que a su vez reduce de manera permanente una fuente importante de secuestro de  carbón de la atmosfera”, agregó.

América Latina contiene la superficie compacta más grande de bosque tropical del mundo, así como vastos bosques templados, es decir, alrededor del 22 por ciento de todos los bosques del planeta, aseguró Torres. Y continuó: “Al interior de la región, aproximadamente el 90 por ciento de las zonas boscosas se encuentra en América del Sur, el 9 por ciento en América Central y México y el 0,4 por ciento en el Caribe. Tenemos que proteger los bosques de esta región y del planeta en su conjunto”.

La creciente demanda global de alimentos y de productos  tales como el café, la carne, la soja, el aceite de palma y la madera contribuye significativamente a la deforestación. Y la mayoría de los países con bosques tienen alternativas limitadas para generar crecimiento económico. De acuerdo a Torres, se requiere generar “condiciones comerciales favorables para productos no madereros con considerable valor añadido,  que hagan al manejo sustentable de los bosques y que provean los incentivos necesarios para reducir la deforestación”.

Las tasas de deforestación a nivel mundial contribuyen con el 15 al 20 por ciento de las emisiones globales de gases con efecto invernadero, lo que tiene un impacto directo tanto sobre el cambio climático como en la reducción de la biodiversidad. Así lo indicó la economista Emma Torres, Asesora Principal de Medio Ambiente y Energía de la Dirección Regional de America Latina y el Caribe del Programa de las Naciones Unidas para el Desarrollo.

.


Deforestation in Brazil: This image of the southern Amazon uses satellite data from the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite collected in 2000 and 2001 to classify the terrain into three separate land surface categories: forest (red), herbaceous (non-woody) vegetation like grasses (green), and bare ground (blue). The Amazon’s numerous rivers appear white.

Why is the Brazilian Amazon being Destroyed?

.



http://rainforests.mongabay.com/amazon/amazon_destruction.html

In many tropical countries, the majority of deforestation results from the actions of poor subsistence cultivators. However, in Brazil only about one-third of recent deforestation can be linked to “shifted” cultivators. A large portion of deforestation in Brazil can be attributed to land clearing for pastureland by commercial and speculative interests, misguided government policies, inappropriate World Bank projects, and commercial exploitation of forest resources. For effective action it is imperative that these issues be addressed. Focusing solely on the promotion of sustainable use by local people would neglect the most important forces behind deforestation in Brazil.

Plane view of deforestation in the Amazon

Plane view of deforestation in the Amazon
Location: Southeastern Peru; from Cuzco to Boca Manu

AerialRainforestDeforestation

Image code: aerial-rainforest-Aerial_1026_3227


Brazilian deforestation is strongly correlated to the economic health of the country: the decline in deforestation from 1988-1991 nicely matched the economic slowdown during the same period, while the rocketing rate of deforestation from 1993-1998 paralleled Brazil’s period of rapid economic growth. During lean times, ranchers and developers do not have the cash to rapidly expand their pasturelands and operations, while the government lacks funds to sponsor highways and colonization programs and grant tax breaks and subsidies to forest exploiters.

A relatively small percentage of large landowners clear vast sections of the Amazon for cattle pastureland. Large tracts of forest are cleared and sometimes planted with African savanna grasses for cattle feeding. In many cases, especially during periods of high inflation, land is simply cleared for investment purposes. When pastureland prices exceed forest land prices (a condition made possible by tax incentives that favor pastureland over natural forest), forest clearing is a good hedge against inflation.

Such favorable taxation policies, combined with government subsidized agriculture and colonization programs, encourage the destruction of the Amazon. The practice of low taxes on income derived from agriculture and tax rates that favor pasture over forest overvalues agriculture and pastureland and makes it profitable to convert natural forest for these purposes when it normally would not be so.

A Closer Look at Brazilian Deforestation

Today deforestation in the Amazon is the result of several activities, the foremost of which include:

  1. Clearing for cattle pasture
  2. Colonization and subsequent subsistence agriculture
  3. Infrastructure improvements
  4. Commercial agriculture
  5. Logging



http://rainforests.mongabay.com/amazon/amazon_destruction.html

http://www.mongabay.org/images/external/2006/satellite/sat_braz_101.jpg

.

tens of thousands of fires burning across the Amazon. Typically understory shrubbery is cleared and then forest trees are cut. The area is left to dry for a few months and then burned. The land is planted with crops like bananas, palms, manioc, maize, or rice. After a year or two, the productivity of the soil declines, and the transient farmers press a little deeper and clear new forest for more short-term agricultural land. The old, now infertile fields are used for small-scale cattle grazing or left for waste.


Paving of roads brings change in the Amazon rainforestand the Chinese economy drives road-building and deforestation in the Amazon


leading exporter of soybeans. High soybean prices have also served as an impetus to expanding soybean cultivation.
Philip Fearnside, co-author of a report in Science [21-May-04] and member of Brazil’s National Institute for Amazonian Research in Manaus, explains, “Soybean farms cause some forest clearing directly. But they have a much greater impact on deforestation by consuming cleared land, savanna, and transitional forests, thereby pushing ranchers and slash-and-burn farmers ever deeper into the forest frontier. Soybean farming also provides a key economic and political impetus for new highways and infrastructure projects, which accelerate deforestation by other actors.”
Satellite data from 2004 shows a marked increase in deforestation along the BR-163 road, a highway the government has been paving in an effort to help soy farmers from Mato Grosso get their crops to export markets. Typically, roads encourage settlement by rural poor who look to the rainforest as free land for subsistence agriculture.


selectively loggedare eight times more likely to be settled and cleared by shifting cultivators than untouched rainforests because of access granted by logging roads. Logging roads give colonists access to rainforest, which they exploit for fuelwood, game, building material, and temporary agricultural lands.

balbina dam

.

Other causes of forest loss in Brazil

Historically, hydroelectric projects have flooded vast areas of Amazon rainforest. The Balbina dam flooded some 2,400 square kilometers (920 square miles) of rainforest when it was completed. Phillip Fearnside, a leading expert on the Amazon, calculated that in the first three years of its existence, the Balbina Reservoir emitted 23,750,000 tons of carbon dioxide and 140,000 tons of methane, both potent greenhouse gases which contribute to global climate change.

Mining has impacted some parts of the Amazon Basin. During the 1980s, over 100,000 prospectors invaded the state of Para when a large gold deposit was discovered, while wildcat miners are still active in the state of Roraima near the Venezuelan border. Typically, miners clear forest for building material, fuelwood collection, and subsistence agriculture.

Aerial view of open pit mine in the Amazon rainforest
http://travel.mongabay.com/pix/peru/aerial-rainforest-Flight_1022_1528.html

Aerial view of open pit mine in the Amazon rainforest
Location: Southeastern Peru; from Cuzco to Boca Manu


.
Slavery and Violence in the Amazon

The Amazon has been a place of violence since at least the arrival of European explorers, and the present is no exception. Violent conflicts between large landowners, poor colonists, and indigenous groups over land are not unusual in the Amazon and may be worsening.

The Pastoral Land Commission, a nongovernmental group working in the region, found that land battles in Brazil’s countryside reached the highest level in at least 20 years in 2004. According to the annual report by the organization, documented conflicts over land among peasants, farmers, and land speculators rose to 1,801 in 2004 from 1,690 conflicts in 2003 and 925 recorded in 2002. Tensions reached their peak earlier this year with the high-profile slaying of Dorothy Stang, an American nun who worked with rural poor, by gunmen associated with plantation owners. In response to the murder, the Brazilian government sent in the army to quell violence in the region and promised to step up environmental monitoring efforts.

The government has also stepped up efforts to end slavery in the Amazon. While Brazil officially abolished slavery in 1888, the government acknowledges that at least 25,000 Brazilians work under “conditions analogous to slavery,” clearing land and working for cattle ranches, soy farms, and other labor-intensive industries. Some groups say the true figure could be ten times that amount. In 2005, 4,133 slaves were freed after Brazilian Swat-style teams raided 183 farms.

Important Updates:


Deforestation in the Amazon

Figures for specific causes of deforestation in the Amazon are spotty at best. Below are some rough estimated ranges, based on published data, informal surveys, and other sources.


.

.

Agencia Ciencia y Tecnología Argentina
Agencia CyTA

Con el apoyo inicial de la Fundación Rene Baron y de la entonces Secretaría de Ciencia, Tecnología e Innovación Productiva, la Agencia de Noticias de Ciencia y Tecnología Argentina (Agencia CyTA-Instituto Leloir) comenzó a funcionar formalmente a principios de 2006.
El eje prioritario de trabajo de la Agencia CyTA es la difusión de noticias científicas, entrevistas y material de divulgación destinado a los medios de comunicación gráficos, audiovisuales y digitales. La popularización de investigaciones desarrolladas por especialistas argentinos o instituciones dedicadas a la ciencia y la tecnología en el país constituye, en ese contexto, una prioridad.
La información producida por CyTA es enviada periódicamente, de manera gratuita,  a través del correo electrónico a sus subscriptores, quienes suelen ser periodistas e integrantes de diferentes medios de comunicación. También consultan el material producido por CyTA docentes y funcionarios, y público en general.
Las novedades son a su vez incorporadas al portal www.agenciacyta.org.ar. Desde allí, medios nacionales y un número considerable de portales de España, Brasil, Chile, Bolivia, Uruguay, Perú, Colombia, Venezuela, México, Cuba y República Dominicana, entre otros países, suelen tomar la información para hacerla llegar a su público.
Se requiere la mención completa de la fuente (Agencia CyTA-Instituto Leloir) para poder disponer del material.
Informes: agenciacyta@leloir.org.ar

[PDF]

e Cuánto Vaien la biodiversidad y los ecosistemas  - PNUD en Perú

www.pnud.org.pe/data/noticia/Caretas%2022%20de%20setiembre.pdf

Formato de archivo: PDF/Adobe Acrobat - Vista rápida
PNUDvaloriza peso económico de ecosistemas. r tan serios desafíos para mantener tal condición. Emma Torres, ase- sora principa] del PNUDpara la región 

Deforestation Figures for Brazil

Year
Deforestation
[sq mi]
Deforestation
[sq km]
Change
[%]
1988 8,127 21,050
1989 6,861 17,770 -16%
1990 5,301 13,730 -23%
1991 4,259 11,030 -20%
1992 5,323 13,786 25%
1993 5,751 14,896 8%
1994 5,751 14,896 0%
1995 11,220 29,059 95%
1996 7,012 18,161 -38%
1997 5,107 13,227 -27%
1998 6,712 17,383 31%
1999 6,664 17,259 -1%
2000 7,037 18,226 6%
2001 7,014 18,165 0%
2002 8,260 21,651 17%
2003 9,805 25,396 19%
2004 10,722 27,772 9%
2005 7,341 19,014 -31%
2006 5,515 14,285 -49%
2007 4,498 11,651 -18%
2008 4,984 12,911 11%
2009 2,889 7,484 -42%

All figures derived from official National
Institute of Space Research (INPE) data
.Individual state figures.

*For the 1978-1988 period the figures represent
the average annual rates of deforestation.

Cattle ranches 65-70%
Small-scale, subsistence agriculture 20-25%
Large-scale, commercial agriculture 5-10%
Logging, legal and illegal 2-3%
Fires, mining, urbanization, road construction, dams 1-2%
Selective logging and fires that burn under the forest canopy commonly result in forest degradation, not deforestation. Therefore these factor less in overall deforestation figures.
Por cinabrio - Publicado en: ECOCIDIO
Escribir un comentario - Ver los 1 comentarios
Volver a la página principal

Présenta

  • : cinabrio blog
  • cinabrio blog
  • : Ciencia
  • : Ecología y sostenibilidad socioambiental, énfasis en conservación de ríos y ecosistemas, denuncia de impacto de megaproyectos. Todo esto es indesligable de la política y por ello esta también se observa. Ecology, social and environmental sustainability, emphasis on conservation of rivers and ecosystems, denounces impact of megaprojects. All this is inseparable from politics, for it, the politics is also evaluated.
  • Recomendar este blog
  • Volver a la página principal
  • Contacto

Créer un Blog

Recherche

Calendrier

September 2014
M T W T F S S
1 2 3 4 5 6 7
8 9 10 11 12 13 14
15 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30          
<< < > >>

Perfil

  • cinabrio
  • cinabrio blog
  • Biólogo desde hace más de treinta años, desde la época en que aún los biólogos no eran empleados de los abogados ambientalistas. Actualmente preocupado …alarmado en realidad, por el LESIVO TRATADO DE(DES)INTEGRACIÓN ENERGÉTICA CON BRASIL
Crear un blog en OverBlog - Contacto - C.G.U - Remuneración por el programa "Gana con tu Blog" - Reportar un abuso - Artículos más comentados