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CLIMATIC CHANGES IN SOUTH BRAZILIAN AMAZONIA (Alta Floresta/MT, São Benedito/PA): A COMPARISION BETWEEN LAND USE CHANGE AND PALEOCLIMATIC RECORDS. Renato.

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Presentation on theme: "CLIMATIC CHANGES IN SOUTH BRAZILIAN AMAZONIA (Alta Floresta/MT, São Benedito/PA): A COMPARISION BETWEEN LAND USE CHANGE AND PALEOCLIMATIC RECORDS. Renato."— Presentation transcript:

1 CLIMATIC CHANGES IN SOUTH BRAZILIAN AMAZONIA (Alta Floresta/MT, São Benedito/PA): A COMPARISION BETWEEN LAND USE CHANGE AND PALEOCLIMATIC RECORDS. Renato de Aragão Ribeiro Rodrigues Orientador: Dr. Renato Campello Cordeiro Co-orientador: Dr. Bruno Jean Turcq

2 PALEOCLIMATIC STUDIES

3 Adaptaded from Ruddiman, 2001 PALEOCLIMATIC RECORDS

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6 CO 2 and Temperature 2005

7 Business as Usual (fossil intensive) 2100 CO 2 and Temperature

8 Turcq et al., 2002 CSS2

9 Levoglucosan – Study case Levoglucosan – Study case Elias et al., 2001 Biomass burning – dryer periods

10 GLOBAL CLIMATE CHANGES CO 2 : CO 2 : LGM ppmv LGM ppmv Before Industrial Revolution 280 ppmv Before Industrial Revolution 280 ppmv ppmv ppmv ppmv ppmv 1850– – 120 Gt C (Forest fires) 1850– – 120 Gt C (Forest fires) 165 Gt C (Fossil fuel) 165 Gt C (Fossil fuel) Burning of fossil fuel 5,6 Gt C.ano -1 Burning of fossil fuel 5,6 Gt C.ano -1 Biomass burning 2,4 Gt C.ano -1 Biomass burning 2,4 Gt C.ano -1 Biomass burning could had influenced the atmospheric CO2 in the past. Biomass burning could had influenced the atmospheric CO2 in the past. Source: Keeling, 2005

11 years BP: 25 ppmv CO 2 concentration. Input of ~ 260 Gt C to the atmosphere. Origin? H1: Only variations in biomass burning; H2: Biomass burning + SST H3: CaCO 3 cycle. H4: C org sea cycle Land biomass Indermuhle et al., 1999 Nature

12 Carajás (PA) Forest fires in the Holocene were recorded by charcoal fragments in many sites in Brazil. The hypothesis that these holocenic events would be related to a global carbon cycle is noted by the relation with the Taylor Dome Ice Core. Comparision between the charcoal particles fluxes in N4 lake, Serra Norte dos Carajás (Cordeiro, 1995), lake Caracaranã, RR (Simões Filho, 2000), lake Dom Helvécio, MG (Albuquerque, 1998) e Pata lake, AM (Mendes, 2004).

13 Amazonic Climatic Changes during the Holocene

14 Lower and middle Holocene: Dry phase! - Savanas expansion in RO and AM (Pessenda et al., 1998; de Freitas et al., 2001). - Forest fires between 7000 and 3000 yr BP in Pará (Turcq et al., 1998); - Savanas pollen and fires in Bolívia (Mayle et al., 2000); - Titicaca – 8500 and 4500 yr BP – the dryest period of the last yr BP (Baker et al., 2001); - This dry phase (8500 and 4500 yr BP) was recorded in many others South American sites: - Carajás (Absy, 1991 e Cordeiro, 1995); - Magdalena Cauca-San Jorge, Colômbia (Van der Hammen, 1991); - Lago La Yeguada, Panamá (Bush et al., 1992); - Lago Ayauch, Equador (Bush e Colinvaux, 1988)

15 Upper Holocene: Wetter phase. - Expansion of the forest (Mayle et al., 2004) - Precipitation increases in Bolivian Chaco (palinological studies). (Mayle et al., 2004); - Smaller charcoal concentrations in Carajás, PA (Turcq et al., 1998); The carbon reservoir in Amazonia in this period was the biggest of the last yr BP. (Behling, 2001)

16 Hypothesys: - The middle holocene dry phase extended until the south Amazonia. - There is a conexion between a possible dry phase in this study area with the CO 2 increase in Taylor Dome, Antartica. - The biomass burning events in the Holocene produced smaller impacts than the land use change (in the present).

17 Major Objective Identificate the occurence and dimensions of forest fires, by sediment cores in lakes and dams in the Alta Floresta region in different time scales. Identificate the occurence and dimensions of forest fires, by sediment cores in lakes and dams in the Alta Floresta region in different time scales.

18 Alta Floresta (MT) - Land use change events

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21 Results

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27 Mudanças no uso da terra Mudanças paleoambientais Deposição atmosférica Charcoal particles fluxes Land Use Change Paleoclimate Changes Atmospheric Deposition

28 What do we want? Increase the date base about the biomass burning proxies in different time scales; Increase the date base about the biomass burning proxies in different time scales; Determinate the cronology of changes between dry and wet phases, linkage with the CO2 increase in Taylor Dome and the charcoal fluxes in Amazonia and Atlantic Forest. Determinate the cronology of changes between dry and wet phases, linkage with the CO2 increase in Taylor Dome and the charcoal fluxes in Amazonia and Atlantic Forest.

29 Thanks!


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