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

PALEOCLIMATIC STUDIES

Adaptaded from Ruddiman, 2001

PALEOCLIMATIC RECORDS

CO2 and Temperature

2005

“Business as Usual”(fossil intensive)

2100

CO2 and Temperature

Turcq et al., 2002

CSS2

Levoglucosan – Study case

Elias et al., 2001

Biomass burning –

dryer periods

GLOBAL CLIMATE CHANGES

CO2: LGM 180-200 ppmv Before Industrial Revolution 280 ppmv 1958 315 ppmv 2006 384 ppmv

1850–1980 90 – 120 Gt C (Forest fires)

165 Gt C (Fossil fuel)

Burning of fossil fuel 5,6 Gt C.ano-1

Biomass burning 2,4 Gt C.ano-1

Biomass burning could had influenced the atmospheric CO2 in the past.

Source: Keeling, 2005

7000-1000 years BP:

25 ppmv CO2 concentration.

Input of ~ 260 Gt C

to the atmosphere. Origin?

H1: Only variations in biomass burning;

H2: Biomass burning + SST

H3: CaCO3 cycle.

H4: Corg sea cycle

Land biomass

Indermuhle et al., 1999 Nature

1000

2000

3000

4000

5000

6000

7000

8000

9000

C a lib ra d a AP

Pa rtic u la s. ,c m .yr

Ro ra im a Do m He lvé c i (M G )

-2 -1

1 5 7 1 2 3 4

1 0 1 0 1 0

3 1 2 3 1 0

4 23

Pa rtic u la s. c m .yr Pa rtic u la s. c m .yr-2 - 1

-2 -1

Ta ylo r Do m e Antá rtid a

- 6.7 - 6.5 - 6.3 C C O p p m

1 3

2

260 27 0 28 0 290 2 4 666 810

4

Pa rtic u la s. c m .yr-2 -1

Sa o G a b rie l (AM )oCarajás (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).

Amazonic Climatic Changes during the Holocene

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 25000 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)

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 21000 yr BP. (Behling, 2001)

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 CO2 increase in Taylor Dome, Antartica.

- The biomass burning events in the Holocene produced smaller impacts than the land use change (in the present).

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.

Alta Floresta (MT) - Land use change events

Results

0,0E+00

2,5E+05

5,0E+05

7,5E+05

1,0E+06

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

Idades calendário (AC/DC)

N°

of

char

coal

par

ticu

les

flu

x (n

°/cm

²/yr

)

0

100000

200000

300000

400000

500000

600000

700000

800000

Pro

du

to In

tern

o B

ruto

Bra

sile

iro

(x

10*3

)

Fluxo de Partículas de Carvão

0

20000

40000

60000

80000

100000

120000

140000

160000

180000

200000

Ror M

ed

Ror M

ax

LP L

GM

CSS93/6

méd

ia

PV úm

ido

LP A

pLG

M

LP A

nLG

M

LP m

édia

PV Sec

o

CSS93/6

atu

al

CSN 93/

3 HS

CSN 93/

3 at

ual

CSN 93/

3 HM

CSN 93/

3 HS

PV méd

ia

CSN 93/

3 m

ax

CSS93/6

max

HS

CSS93/2

atu

al

Saci m

édia

PV máx

imo

em M

aio

CSS 93/

2 m

édia

CSS93/6

max

CSS 93/

2 HS

AF IC

CSS 93/

2 HM

AF m

édia

Saci m

ax

CSS93/2

max

AF m

áxim

o

(n°/

cm²/

ano

)

Mudanças no uso da terra

Mudanças paleoambientais

Deposição atmosférica

Charcoal particles fluxes

Land Use Change

Paleoclimate Changes

Atmospheric Deposition

What do we want?

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.

Thanks!