Research

53 pages
132 views

Fires in the Brazilian Amazon: greenhouse gas emissions from burning of different ecosystems in Roraima during the 1997-98 El Niño event

Please download to get full document.

View again

of 53
All materials on our website are shared by users. If you have any questions about copyright issues, please report us to resolve them. We are always happy to assist you.
Share
Description
Area burned, total biomass above and below-ground, charcoal formation, burning efficiency and the carbon concentration were estimated in the different natural landscapes and agricultural systems that were exposed to fire during the El Niño event of
Transcript
   1 FIRES IN THE BRAZILIAN AMAZON: GREENHOUSE GAS EMISSIONS FROM BURNING OF DIFFERENT ECOSYSTEMS IN RORAIMA DURING THE 1997-98 EL NIÑO EVENT Reinaldo Imbrozio Barbosa National Institute for Research in the Amazon (INPA) CTA-Conv. INPA/GERR Caixa Postal 96 69301-970 Boa Vista, Roraima tel/fax +55 (95) 623 9433 e-mail: imbrozio@technet.com.br Philip Martin Fearnside National Institute for Research in the Amazon (INPA) Department of Ecology Caixa Postal 478 69011-970 Manaus, Amazonas tel +55 (92) 643 1822 fax +55 (92) 642 8909 e-mail: pmfearn@inpa.gov.br Updated and corrected translation of: Barbosa, R.I. and P.M. Fearnside. 1999. Incêndios na Amazônia brasileira: Estimativa da emissão de gases do efeito estufa pela queima de diferentes ecossistemas de Roraima na passagem do evento "El Niño" (1997/98). Acta Amazonica 29(4): 513-534. 4 April 2000   2 TABLE OF CONTENTS Abstract Keywords Introduction ............................................... General description of the Area ............................ Area of the Natural Systems and Agroecosystems Affected Original area ......................................... Area Burned ........................................... Total Original Plant Biomass Present biomass ....................................... Forest arboreal biomass killed by the fire ............ Formation of Charcoal ...................................... Burning efficiency ......................................... Concentration of Carbon .................................... Fate of Carbon Affected by the Fire ........................ Gross emissions of Greenhouse Gases ........................ Conclusions ................................................ ACKNOWLEDGMENTS ............................................ LITERATURE CITED ........................................... FIGURE LEGENDS .............................................   3 Abstract Area burned, total biomass above and below-ground, charcoal formation, burning efficiency and the carbon concentration were estimated in the different natural landscapes and agricultural systems that were exposed to fire during the El Ni ñ o event of 1997-98 in the state of Roraima, in the northernmost part of the Brazilian Amazon. Total area burned was 38,144-40,678 km 2 , of which 11,394-13,928 km 2  was intact primary forest, 22,583 km 2  was savanna, 1,388 km 2  was white-sand scrub formations, and 2,780 km 2  was pasture, secondary forest and agricultural plots. Total carbon affected by the fire was 45.63 ×  10 6  metric tons (t), with 18.90 ×  10 6  t being released from combustion, 26.21 ×  10 6  t from decomposition, and 0.52 ×  10 6 t converted to charcoal (long-term carbon storage). Based on a range of published emission factors for different greenhouse gases, gross emissions from combustion were 60.8 ×  10 6 t CO 2 , 0.18-0.22 ×  10 6  t CH 4 , 4.42-5.56 ×  10 6  t CO, 0.001-0.003 ×  10 6  t N 2 O, 0.06-0.09 ×  10 6  t NO x  and 0.68 ×  10 6  t NMHC (non-methane hydrocarbons). The total emission from combustion in CO 2 -equivalent carbon, based on the IPCC global warming potentials of each gas over a 100-yr horizon, was 17.7-18.0 ×  10 6  t C. Keywords: forest fires, carbon, Amazonia, Roraima, greenhouse effect, El Ni ñ o, global warming.   4 Introduction Forest fires of great proportions in areas with high humidity in Amazonia could be considered as rare events, and only a short while ago few people would have believed that real a danger existed of such fires taking place (Uhl et al., 1988; Kauffman, 1991; Nelson and Irm ã o, 1998). However, in late 1997 and early 1998, fires penetrated primary forests and other types of ecosystems of the state of Roraima, located in the extreme north of the Brazilian Amazon (Barbosa, 1998a,b,c; Brazil, IBAMA, 1998; Brazil, INPE, 1998, 1999a; Shulze, 1998). Fires in savannas and transformed forest systems (secondary forests, pastures and clearings), which are traditionally burned at this time of year, spread over thousands of square kilometers of intact primary forest, provoking the death of trees and the emission of million of tons of greenhouse gases to the atmosphere. The enormous size of the fire was credited, mainly, to the drought provoked by the strong El Ni ñ o phenomenon of 1997-98. However, the occurrence of the Great Roraima Fire should not be seen as an event caused exclusively by this climatic effect. Instead, it was the result of a series of factors acting simultaneously, with the El Ni ñ o aggravating the effect of the pre-existing conditions. At present, the probability of events such as this can be expected to increase over time due to pressure of human settlements in forest areas throughout Amazonia, amplified by the increasing logging, clearing for agriculture and burning for conversion of primary forests to pastures, all increasing the vulnerability of the adjacent forests (Cochrane et al., 1999; Kauffman et al., 1988; Negreiros et al., 1996; Nepstad et al., 1999a,b). Studies are rare that try to evaluate the risks of fires in Amazonia and their release of greenhouse gases. With the growth of human activities in the Amazon, there is a need to increase the volume of information on the impacts that this type of event can cause at regional and global levels. With this in mind, we calculated the emissions of greenhouse gases provoked by the fires in Roraima in different types of natural systems and agroecosystems that were affected by fire in 1997 and 1998. In order to calculate these emissions we estimated the following parameters: (a) the area of each natural   5 system and agroecosystem affected, (b) the total plant biomass (above and below ground) per unit of area, (c) mortality of trees due to the fire, (d) the formation of charcoal in the systems affected, (e) burning efficiency for the different biomass categories that it comprise each system and (f) the concentration of carbon in each of these categories. General description of the Area Roraima is one of the former federal territories transformed into states by Brazil ’ s 1988 constitution, located in the northernmost portion of the Brazilian Amazon. The local population tripled between 1980 and 1998, growing from 82,018 to 260,705 inhabitants (Brazil, IBGE, 1999). The migratory explosion of this period was motivated by local public authorities in three phases: (a) at the end of the 1970s, with support of the Federal Government as part of the POLORORAIMA sub-program of the Amazonian Development Poles Program (POLOAMAZ Ô NIA), (b) through the “ mining boom ”  in the Yanomami indigenous lands at the end of the 1980s, when the territory was transformed into a state and (c) in the early 1990s through state government programs to recruit migrants in other parts of the country with land-tenure problems (Barbosa, 1993). The population growth provoked an increase by 55.6 fold in the total area of deforestation, expanding from 100 km 2  in 1978 to 5,560 km 2  in 1997 (Brazil, INPE, 1999b). The natural vegetation of Roraima is a mosaic of landscapes that range from savannas (northeast) to forests (south and west), and different types of oligotrophic (nutrient-poor) systems such as campos (grasslands), campinas and campinaranas (low woodlands on white-sand soils) in the center-south portion of the state (Silva, 1997). The annual precipitation is variable and forms a gradient from 1000 mm (in the savannas at the northeast end of the state) up to 2300 mm (southern and far western parts of the state) (Barbosa, 1997). The place with largest volume of climatic data is the capital at Boa Vista. The annual average precipitation is 1614 mm (1910 to 1995). Between September 1997 and March 1998 the precipitation was only 30.6 mm in this area, when the expected amount based on the historical average for same period would be 352 mm (Brazil, DEFARA
Related Documents
View more...
We Need Your Support
Thank you for visiting our website and your interest in our free products and services. We are nonprofit website to share and download documents. To the running of this website, we need your help to support us.

Thanks to everyone for your continued support.

No, Thanks
SAVE OUR EARTH

We need your sign to support Project to invent "SMART AND CONTROLLABLE REFLECTIVE BALLOONS" to cover the Sun and Save Our Earth.

More details...

Sign Now!

We are very appreciated for your Prompt Action!

x