- Past climate changes : general presentation and tools - Antarctic ice cores : from Byrd to Vostok - - Greenland ice cores : from Camp Century to GRIP/GISP2.

- Past climate changes : general presentation and tools

- Antarctic ice cores : from Byrd to Vostok-

- Greenland ice cores : from Camp Century to GRIP/GISP2- Historical overview- GRIP and GISP 2 rapid changes

- Dating strategy Isotope :temperature- Dating strategy

- Rapid changes in the North Atlantic- Geographical extension of rapid cahnges- Greenland / Anatarctica- The 8.2 K event

- Ongoing projects : EPICA, North GRIP and others

GRIP and GISP2 (Central Greenland) ; North GRIP

Les forages glaciaires

au GROENLAND

-44

-40

-36

-32

10080604020Age [kyr BP]

-44

-40

-36

-32

18O

[‰

]

-44

-40

-36

-32

-44

-40

-36

-32

GRIP ss09 ages 50 yr

GRIP ss09sea ages 50 yr

GISP2 "counted" and SPECMAP

GRIP stratigraphic chronology

GRIP/GISP2 time scale comparison

Below 2700 m (~ 100 000 years) the two profiles diverge due to ice flow disturbances

12

10

8

6

4

2

d (

deu

t e

xcess)

‰

16151413121110

age (kyr)

-320

-300

-280

-260

D

(‰

/sm

ow

)

GRIPD

d excess

YD

The last deglaciation

d = D - 8 * 18O

12

8

4

d (d

eu

t excess) ‰

6050403020

age (kyr)

-320

-280

D (

‰/s

mow

)GRIPD

d excess

The glacial period : the Dansgaard / Oeschger events

D0 8D0 12

-42

-40

-38

-36

-34

-32

18 O

(‰

)

26

00

25

00

24

00

23

00

22

00

21

00

20

00

19

00

18

00

17

00

16

00

15

00

14

00

13

00

Depth (m)

25

20

15

10

5

0

Te

mp

era

ture

ch

an

ge

14.5 21 34.8 68.5

YD

Bølling

LGM

D/O9 D/O19

HOLOCENE

8.2 11.6

GRIP Ice Core 20°C

Review of independent temperature estimates : Jouzel (1999)Differences largely due to seasonality (Krinner et al., 1997 ; Werner et al., 2000)

1716151413121110

Calendar Age (ka)

0.25

0.20

0.15

0.10

0.05

GIS

P2 A

ccum

ulatio

n (m

/yr)

-42

-40

-38

-36

-34

GIS

P2 1

8 Oic

e (

‰)

0.60

0.50

0.40GIS

P2 1

5 N (

‰)

700

600

500

400

Meth

ane (p

pb

V)

GISP2 Taylor Dome

Severinghaus et al. (Nature, 1998)Severinghaus and Brook (Science, 1999)

Rapid 15N changes caused by thermal and gravitational processes

Combined use of 15N /14N and 40Ar/ 36Ar isotopic ratios allows precise estimate of the associated temperature change

Comparison of the ice and gas records allow direct estimate of the firn thickness and of the gas age/ ice age difference

Direct comparison of gas records (e.g. CH4, CO2 ….) with rapid temperature change

Method also useful for Antarctica(Cf Caillon et al., Science, 2003 who inferred the timing between CO2 and temperature change at Termination 3

Le névé

18Oglace et

Dglace

= f (T°C)

Zone convective

Zone diffusive

Zone non-diffusive

CLOSE-OFF

névé

glace

même âge

âge

Dans les bulles d'air :

Age de l'air différent de l'âge de la glace : âge

40Ar et 15N = f ( T°C , Accumulation…) [CH4] , [CO2], 18Oatm …

Le névé

18Oglace et

Dglace

= f (T°C)

Zone convective

Zone diffusive

Zone non-diffusive

CLOSE-OFF

névé

glace

même âge

âge

Dans les bulles d'air :

Age de l'air différent de l'âge de la glace : âge

40Ar et 15N = f ( T°C , Accumulation…) [CH4] , [CO2], 18Oatm …

Zone convective

Zone diffusive

Zone non-diffusive

CLOSE-OFF

névé

glace

même âge

âge

Zone convective

Zone diffusive

Zone non-diffusive

CLOSE-OFF

névé

glace

même âge

âge

Dans les bulles d'air :

Age de l'air différent de l'âge de la glace : âge

40Ar et 15N = f ( T°C , Accumulation…) [CH4] , [CO2], 18Oatm …

18

19

20

40Ar and 15N measurements combined with a firn model allow precise estimates of Tsite : 10°C (18 and 20), 15°C (19) ;

Landais et al. (In preparation)

North GRIP

Rapid changes in the North Atlantic

Découverte de variations climatiques rapides dans le passé ( ~ 10°C en quelques décennies)Groenland, atlantique nord, continents..

Modifications du cycle hydrologiqueliées à la décharge massive d’icebergs

Risque de surprise climatique dans un climat plus chaud (apport d’eaudouce à travers des précipitations

Geographical extension of rapid changes

1000 1100 1200 1300

AS96-1NR [depth, cm]

-8

-7

-6

-5

-4

18O

cs

Mid-Europe [‰ PDB]

5000 6000 7000 8000 9000 10000 11000 12000 13000 14000 15000

GRIP Ice-core chronology [years] -42

-41

-40

-39

-38

-37

-36

-35

-34

18Oice Centr.Greenl. [‰ SMOW]

500 600 700 800 900 1000

AS92-5 [depth, cm]

700 800

AS93-1 [depth, cm]

Lake sediments in Bavaria, Germany ; von Grafensteinet al., Scienc, 2001

Genty et al. (Nature, soumis ) 

Stalagmite de la grotte de Villars

30000 35000 40000 45000 50000 55000 60000 65000 70000 75000 80000 85000

-10

-9

-8

-7

-6

-5

-42

-40

-38

-36

-44

-42

-40

-38

-36

-34

1

2

3

age yr

Vil9

C

GRIP

ss

09

Sore

q Ca

ve

C

GISP

2M

D 95- 2

042

-10

-9

-8

-7

-6

-5

Hulu

Cave

,

-12

-11

-10

-9

-8

-7

7 810

11

12

13

14

16 1719 20

6 78

9 10 1112

13

1416

17

18

19 20

8 101112

7 1314 16 17

18

1920

7 8 10 11 12 13 14 1617

192010

11 12 13

8 12 1419 20

D2D3D4 D1D5D6D7

H6H5b

Pla

nk.

2012

GRIP

ss09

sea

French cave200 km from the ocean

Genty et al. Nature, 2003

Hulu Cave, East of Nanjing (China) :Wang et al. (Science, 2001)

Dongge cave, Guizhou Province : Yuan et al. (Science, 2004)

Greenland / Antarctica

Blunier and Brook, Science, 2001

Corrélations Nord-Sud

De 10 000 à 90 000 ans

8.2 K event : a rapid event cooling during a warm period

The day after tomorrow

2.00

1.95

1.90

1.85

4

0Ar (‰

)

15801560154015201500

profondeur (m)

-480

-475

-470

-465

-460

-455

-450

D

(‰

)

650

600

550

500

450

CH

4 (

ppbv

)

0.49

0.48

0.47

0.46

15N

(‰

)

prof = 32 m

âge ~ 5100 ans

prof = 64 ± 2 m

âge ~ 2500 ans

âge ~ 2600 ans

D CH4 (1999)

CH4 (1990)

40

Ar

15

N

Caillon et al., unpublished

Le sud se réchauffe avant le Nord sur toute la dernière période glaciaire avec une

avance de ~2000 ans.

Rôle important joué par la circulation océanique et

l’intensité de la circulation thermohaline dans l’hémisphère Nord.

Corrélations Nord-Sud

Étude de la transition 5d/5c (108 000 ans) 

Raisbeck et al., Goldschmidt Conference, 2002

The 10Be peak straddles event 10, exactly as seen in the GRIP core. This implies that, within our ability to resolve, which we presently estimate as 200 years, the GRIP and

EPICA climaterecords at this time are synchronous.

Small events / Large events ? Interesting modelling approach ofJohnsen and Stocker, Paleoceanography, 2003

High resolution Vostok CH4 record shows millennial-scale variability during MIS 6 and MIS8 (periods of 2 to 7 kyr) : Delmotte et al., In prep , Chappellaz , Euresco, 2003

Detailed water isotope profiles combined with high resolution methane measurements should allow to extend the record of D/O events to previous glacials

5.0

4.5

4.0

3.5

3.0 fora

ms

18O

(‰)

100

100

80

80

60

60

40

40

20

20

0

0

Age (kyr)

1.0

0.5

0.0

-0.5

18 O

atm

(‰

)

-480

-460

-440

Vo

sto

k D

ice

-40

-35

-30 GIS

P2 1

8Oic

e (‰)

700

600

500

400

GIS

P2

CH 4

(pp

b)

8 12

14

16/1719 20

21

18

GISP2

Vostok

V19-30 benthics

GISP2 CH4

Vostok Dice

GISP2 18Oice

Bender.M., Malaizé, B.,Orchado, J., Sowers, T, Jouzel, J Geophysical Monograph , 1999