GREENHOUSE GAS (CO2, CH4) AND CLIMATE

EVOLUTION SINCE 650 KYRS DEDUCED FROM ANTARCTIC ICE CORES

EPICA gas consortiumJ.-M. Barnola (1), U. Siegenthaler (2), E. Monnin (2), R. Spahni (2), J. Chappellaz

(1),T.F. Stocker (2), D. Raynaud (2) and H. Fischer (3)  (1) Laboratoire de Glaciologie et Géophysique de l’Environnement, Grenoble

France (2) Climate and Environmental Physics, Physics Institute, Bern, Switzerland (3) Alfred-Wegener-Institut (AWI), Bremerhaven, Germany

How the gas are trapped ?

What constraints do we have on the air trapping ?

Implication on the phase relationship

CO2 and CH4 records during the last climatic cycles

Results based mainly from :

Russian US French program of VOSTOK

European programs GRIP (Greenland) and EPICA (Antarctica)

Plan of the presentation

Antarctic Drilling sites

Vostok

Dome CByrd

Dome F

DML

120

100

80

60

40

20

0

de

pth

(m

)

0.3 0.4 0.5 0.6 0.7 0.8 0.9Density

100

500

1 000

2 000

2 600

2 900

0 0.02 0.04 0.06 0.08Closed Porosity

260 280 300 320 340 360 380CO 2 concentra tion (ppm v)

120

100

80

60

40

20

0

Air hydrates

Yea

rs a

fter

the

snow

fall

M ateria l evo lu tionG as evo lu tion

Vostok firn

Densification and gas trapping

Snow

Firn

Ice

Densification of polar firn : 3 main stagesDensification of polar firn : 3 main stages

First meters :evaporation-condensation

and surface diffusionStructural rearrangementby grain boundary sliding 0.35 < < 0.55 g/cm3

Plastic deformationof contact areas

0.55 < < 0.85 g/cm3

Plastic deformation ofice matrix surrounding

cylindrical or spherical pores ~ 0.92 g/cm3

Good agreement betweenmodel and density measurements

Model

Snow : Alley

Firn : Arzt

(Arnaud et al., 2000)

0 . 2 0 . 6 1

D e n s i t y ( g / c m 3 )

1 2 0

8 0

4 0

0

Dep

th (

m)

D0

Dc

Snow

Firn

Ice

Present day Close Off :

Depth : 98 m

Age : 2800 years

Smoothing : ~ 250 years

Full Glacial Close Off :

Depth : 120 - 140 m

Age : 6500 – 7400 years

Smoothing: ~ 600 years0.3 0.4 0.5 0.6 0.7 0.8 0.9

density

140

120

100

80

60

40

20

0D

ep

th (

m)

Ag e a t .8 4 d e n sity

SAE 15 data 2850 yrs

H erron-Langw ay 2850 yrs

P im ienta 2950 yrs

A lley-A rzt 2800 yrs

H erron-Langw ay 7400 yrs

P im ienta 6750 yrs

A lley-A rzt 6450 yrs

DENSIFICATION MODEL PREDICTIONS :VO STO K INTERG LACIAL (-55°c, 2 .2 g/cm 2.yr)

AND G LACIAL (-65°c, 1.2 g/cm 2.yr)

Under present-day conditions :- Gas are trapped 70 m (« warm » sites) 100 m (cold sites) below the surface.- Gas are trapped 200 yrs –3000 yrs after the snow deposition

Air linked signals recorded deeper than ice linked signals.Air linked signals are younger than ice linked signals.

Model prediction for glacial times :Gas trapped deeper than during present day due to colder condition. Gas age difference up to 7000 years due to lower accumulation.

Possible constraints on close-off depth through gravitational and Thermal fractionation of permanent gas isotopes.(Schwander et al, Sowers et al, Severinghaus et al)

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

*1 5 N o u *4 0 A r (p er m il)

100

90

80

70

60

50

40

30

20

10

0

Pro

fond

eur

(m)

0.2 0.4 0.6 0.8 1

D en sité

* 1 5 N * 4 0 A r

-36 -32 -28 -24 -20 -16Te m p é ra tu re (°C )

100

90

80

70

60

50

40

30

20

10

0

Pro

fon

de

ur

(m)

Fractionnem ents therm iques et gravita tionnels à N orth-G R IP (G roenland)

Thermal and Gravitational fractionation at N-GRIP

(A. Landais et al, 2004)

Convection zone

Diffusion zone

Non diffusive zone

Close-Off

Heavier molecules enriched in colder zone and in deeper part of the firn.In case of abrupt temperature change strong thermal gradient in the firn can exist which can be recorded by through the isotopic composition.

See also Poster U. Seibt FF351

Model and isotopes are in good agreement in Greenland

Different prediction during glacial times in Antarctica : Models predict deeper close off depth, while isotopes give thinner diffusive zone

However : -From the comparison of different cores the modeled age at the close off is right - Isotopes and modeled firn ice thickness equivalent are the same (Blunier et al, Bender et al, G Dreyfus).

Conclusion :Even if the model and isotopes disagree on the depth, the two approach are coherent for the age of the gas at the close off

Comparison Models –Isotopes for the glacial conditions

2440 2460 2480 2500 2520 2540 2560 2580 2600 2620 2640D e p th (m )

0.35

0.4

0.45

0.5

0.55

0.6

15 N

(0 /

00)

-46

-44

-42

-40

-38

-36

18 O

(0 /

00

)

400

440

480

520

560

CH

4 (p

pbv)

18O : tem perature proxy linked to the ice phase

15N tem perature proxy linked to the gas phase

Adapted from A. Landais (2004)

D O 18

D O 19

D O 20

DO 21

15N allows to avoid the problem of the gas age-ice age differenceCH4 in phase with Greenland temperature

CH4 in Antarctic cores can be used as a time marker of Greenland Temp for the pre-Eemien times

CH4 - temperature timing from N2 isotopes

Previous glacial periods

High resolution Vostok CH4 record shows millennial-scale variabilityduring MIS 6 and MIS8 (periods of 2 to 7 kyr) Delmotte et al (2004)

MIS 6 MIS 8

• During major stadials/interstadials,

• Antarctica warms up when Greenland is cool, and it starts to cool down when Greenland suddenly warms up

Blunier et al., Nature, 1998

North-south correlation based on CH4

Blunier et Brook, Science, 2001

Rahmstorf, Nature, 2002

Blunier et al., Nature, 1998

Modeled delta age

Byrd :600 years

Vostok : 6000 years

The good agreement between ice linked and gas linked information adds confidence in modeled ages and phase relationships deduced

Modeled delta age

Byrd :600 years

Vostok : 6000 years

The good agreement between ice linked and gas linked information adds confidence in modeled ages and phase relationships deduced

Stadials and interstadials

CO2 : 20 ppmv variability correlated with Antarctic temperature

CH4 : - 100-200 ppbv variability associated with North Atlantic climate shifts - synchronous with t° or lags by a few decades- increases over 50 to 150 yr

Stauffer et al., 2002 and ref. therein

TIME

Glacial-interglacial transition

CO2 : parallels Antarctic warming

CH4 : parallels N. Atlantic warming

N2O : parallels N. Atlantic warming but with slower response than CH4

Stauffer et al., 2002 and ref. therein

TIME

130000 120000 110000 100000 90000

A ge

5

4

3

Na

(L

og

)

- 8

- 6

- 4

- 2

0

2

Tem

pe

ratu

re

400

500

600

700

CH

4 (

ppbv

)

240

260

280

CO

2 (

pp

mv)

- 2

- 3

- 4

- 5

Du

st

(lo

g)

stage 5e Stage 5d Stage 5c

Last g lacia l inception on Vostok

Am ong a ll the param eters m easuredonly D ust and C O 2 have the sam e patternat th end of the in terg lacia l.

D ust are be lieved to be representative o f the sea ice extent around Antarctica

This stress on the in fluence of Southern oceanon the a tm ospheric C O 2

4 last Glacial-interglacial cycles from Vostok

Maximum range of natural changes : CO2 : 185-300 ppmv (~20 ppmv / °C)CH4 : 350-800 ppbv (~75 ppbv / °C)N2O : 200-275 ppbv (~15 ppbv / °C)

Steady-state information is useful, time-dependent information is even more !

Petit et al., Nature 1999Time

Dome Concordia station seen By SPOT(not available on Google Earth)

0 500 1000 1500 2000 2500 3000 3500

D epth (m)

-460

-440

-420

-400

-380

-360

De

ute

riu

m (

0 /00

)

200

400

600

800

1000

CH

4 (

pp

bv

)

160

200

240

280

320

CO

2 (

pp

mv

)

D om e C EPIC A Core

-440

-420

-400

-380

-360

32003000280026002400

-440

-420

-400

-380

-360

8006004002000

4.5

4.0

3.5

3.0

2.5

2.0

Age in kyr BP

Depth in meters

Benthic Oxy18 (Lisiecki and Raymo)

Deuterium EPICA DC

Bottom

Bottom

Deut/Age

Deut/Depth

Benthic 5 7 9 11 13 15 17 19 20

Dating by inverse modeling with 4 control windowsComparison with stacked marine record : Full glacial condition more constant than in marine record, interglacials cooler prior to stage 11.

Time

700000 600000 500000 400000 300000 200000 100000 0

Age (yr BP)

400

500

600

700

800

CH

4 (

pp

bv

)

-10

-8

-6

-4

-2

0

2

4

(

°C)

180

200

220

240

260

280

300

CO

2 (p

pm

v)

Climate and Greenhouse Gases during the last 650 Kyrs

375 ppm v

1700 ppbv

E PIC A D om e CInderm uehle et a l (subm itted)EP IC A pro ject m em bers (2004)Spahni et a l (subm itted)

VostokPépin e t a l ( 2001)Petit e t a l (1999)D elm otte et a l (2004)

440000 420000 400000 380000 360000A ge (yr)

180

200

220

240

260

280

300

CO

2 (p

pm

v)

-480

-460

-440

-420

De

ute

riu

m (

0 /00

)

300

400

500

600

700

CH

4 (p

pb

v)

MIS 11 O N Vostok and D om e C

MIS 11

Tem p : N o clim atic op im um a t the beginn ing of M IS 11. CO2 : C oncentra tion s im ila r to the holocene lag at the g lacia l inception .

CH4 : Lag during the deglacia tion N o lag a t the g lacia l inception.

E PIC A (2004), R aynaud et a l (2005)Inderm uehle e t a l, Spahni e t a l (subm itted)

Very good agreement between Dome C and Vostok

700000 600000 500000 400000 300000 200000 100000 0Age (yr BP)

400

500

600

700

800

CH

4 (p

pb

v)

-10

-8

-6

-4

-2

0

2

4

(

°C)

180

200

220

240

260

280

300

CO

2 (p

pm

v)

Climate and Greenhouse Gases during the last 650 Kyrs

375 ppm v

1700 ppbv

EPIC A D om e CInderm uehle et a l (subm itted)EP IC A pro ject m em bers (2004)Spahni et a l (subm itted)

VostokPépin e t a l ( 2001)Petit e t a l (1999)D elm otte et a l (2004)

280 ppmv260 ppmv

180 ppmv

650 ppbv600 ppbv

350 ppbv

CO2 : Relationship with antarctic temperature remains unchangedGlacial interglacial amplitude lower before stage 11 than afterFull glacial concentration at the same level (185 ppmv) even if sea level is differentMaximum at the very beginning of the last three interglacials

CH4 :Relationship with antarctic temperature remains unchangedGlacial interglacial amplitude lower before stage 11 than afterFull glacial concentration varies (as sea level do ?)

420000 410000 400000 390000A ge (yr)

300

400

500

600

700

CH

4 (p

pb

v)

-12

-8

-4

0

4

Vo

sto

k D

elt

a T

(°C

)

180

200

220

240

260

280

300

CO

2 (

pp

mv

)

MIS 11

140000 130000 120000 110000 100000A ge (yr)

300

400

500

600

700

CH

4 (p

pb

v)

-12

-8

-4

0

4

Vo

sto

k D

elt

a T

(°C

)

180

200

220

240

260

280

300

CO

2 (

pp

mv

)

MIS 5

30000 20000 10000 0 -10000A ge (yr)

300

400

500

600

700

800C

H4

(pp

bv

)

-460

-440

-420

-400

-380

EP

ICA

De

ute

riu

m (

0 /00

)

180

200

220

240

260

280

300

CO

2 (

pp

mv

)

Holocene

In terg lacia l com parison

R aynaud et a l, 2005 Petit e t a l (1999)

Jouzel et a l (2001)F lückiger et a l (2002)M onin e t a l (2004)

- Deglaciation : CO 2 in phase with Antarctic T (or lags about 600 yrs)CH 4 lags (about 1000 years)

- Glacial inception :CH4 in phase, CO2 lags

CO2 : 40 ppmv change with minimum around 7-8000 yr BP

CH4 : 150 ppbv change with minimum around 5000 yr BP

12000 10000 8000 6000 4000 2000 0Age (BP calendar)

600

650

700

CH

4 (p

pb

v)

250

260

270

280

CO

2

M onnin et a l 2001, F lückiger et a l, 2002

G renoble Values

-410

-400

-390

De

ute

rium

Jo u ze l e t a l, 2 0 0 1

7 Kyr

5 Kyr3 Kyr8.2 Kyr

___ Bern CH4

(M onnin et a l,2001, F lückiger et a l, 2002)

G renoble CH4

CO2-CH4 and Antarctic temperature during the Holocene

900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000A g e (A n n ées A .D .)

270

280

290

300

310

320

330

340

350

360

CO

2 (p

pmv)

U .I.B ., C H (S ip le , S o u th P o le )

C .S .I.R .O ., A u s (D E 0 8 , D S S )

C A O S , J (H 1 5 )

L .G .G .E ., F (D 4 7 , D 5 7 )

B arn o la, T el lu s (1 9 9 9 ).

M esu r es a tm o sp h ér iq u es(P ô le S u d )

M esu res issu esd es caro ttes d e g lace

CO2 during the last millenium

CH4 during the last millenium

1000 1100 1200 1300 1400 1500 1600 1700 1800 1900

A ge (yr A D )

640

680

720

760

800C

H4

(p

pb

v)

6 0

5 0

4 0

3 0

2 0

gra

die

nt

(pp

bv

)276

278

280

282

284

286

CO

2 (

pp

mv

)

G reenland (EU R O C O R E)B lunier et a l, G .R .L.,1993

Antarctica (D 47-D 57)C happellaz et a l,J.G .R ., 1997

Synthetic record of Antarctic C O 2Barnola Tellus,1999

CH4 INTER-POLAR GRADIENT DURING THE LAST 1000 years

What is the link between CO2 variation and CH4 gradient ?

Main Conclusion :

CO2 and CH4 Antarctic climate relation remains unchanged during the last 650 Kyrsallthough the features of glacial interglacial cycles have changed around Stage 11.

Why CO2 and CH4 change : CO2 : listen Peter Köhler and see poster from M. Leuenberger (EC-47) and from F. Joos (EC-24)CH4 See posters from S Aoki (FF-213) and J Kaplan (EC-283)