Institut dAstronomie et de Gophysique G Lematre Chemin

Institut d’Astronomie et de Géophysique G. Lemaître Chemin du Cyclotron, 2 1348 Louvain-la-Neuve Paramètres Astronomiques : le métronome des changements climatiques A. Berger et M. F. Loutre Ecole Eté de Physique sur la Physique de notre Planète : la Terre et son Climat, E 2 PHY, Université de Bordeaux I, 25 -28 août 2003

Last Glacial Maximum 21 kyr BP LGM Today DT=-5°C Pre-industrial CO 2 = 280 ppmv Dsea level = – 130 m 2000 AD CO 2 = 370 ppmv Dice volume = +52 106 km 3 CO 2 = 200 ppmv (Joussaume, 1993)

(Paja Jovanovic, 1943)

1. ASTRONOMICAL SOLUTION 2. MATHEMATICS OF INSOLATION 3. MODELLING THE PAST 4. MODELLING THE FUTURE 5. MAN’S IMPACTS ON CLIMATE/ ASTRONOMICAL TIME SCALE

ORBIT-ECC-LATSIS, 2001

ORBIT-O-LATSIS, 2001

ORBIT-11 ky-LATSIS, 2001

0. 0167 • 14 kyr. BP | ~80 kyr SS Aphelion • SS Perihelion 9 kyr. BP | • 23° 4 e large SS Perihelion (v=270°; e sin v min) } High insolation Lat. MAX NH in summer D lat in summer D season in high lat NH } MAX

1. ASTRONOMICAL SOLUTION 2. MATHEMATICS OF INSOLATION 3. MODELLING THE PAST 4. MODELLING THE FUTURE 5. MAN’S IMPACTS ON CLIMATE/ ASTRONOMICAL TIME SCALE

Present day departure from the last 400 kyr average of insolation

105 Wm-2 11 kyr BP 25 Wm-2 9 kyr AP

24 h mean irradiance (Wm-2) Mid-month June

Insolation (Wm-2) Deviation from present day value 115 kyr BP 125 kyr BP

10 kyr. BP departure from the last 400 kyr average of insolation

1. ASTRONOMICAL SOLUTION 2. MATHEMATICS OF INSOLATION 3. MODELLING THE PAST 4. MODELLING THE FUTURE 5. MAN’S IMPACTS ON CLIMATE/ ASTRONOMICAL TIME SCALE

Bertrand et al. , 2002

1. ASTRONOMICAL SOLUTION 2. MATHEMATICS OF INSOLATION 3. MODELLING THE PAST 4. MODELLING THE FUTURE 5. MAN’S IMPACTS ON CLIMATE/ ASTRONOMICAL TIME SCALE

The EXCEPTIONAL astronomical forcing over the next 50 kyr

0. 0167 • 14 kyr. BP | ~80 kyr SS Aphelion • SS Perihelion 9 kyr. BP | • 23° 4 e large SS Perihelion (v=270°; e sin v min) } High insolation Lat. MAX NH in summer D lat in summer D season in high lat NH } MAX

105 Wm-2 11 kyr BP 25 Wm-2 9 kyr AP

24 h mean irradiance (Wm-2) Mid-month June

STAGE 11 / STAGE 1 and its Future

Orbital parameters : an analogue for the future

MIS 11 : an analogue for the future

MIS 11 : an analogue for the future Ref : Petit et al. , 1999

MIS 11 : an analogue for the future CO 2 = Vostok

MIS 11 : other CO 2 scenarios Stage 11 is replaced by stage 9 or stage 5 Stage 11 is made older by 10 kyr or by 20 kyr

1. ASTRONOMICAL SOLUTION 2. MATHEMATICS OF INSOLATION 3. MODELLING THE PAST 4. MODELLING THE FUTURE 5. MAN’S IMPACTS ON CLIMATE/ ASTRONOMICAL TIME SCALE

(Pedersen, IGBP Newsletter 44, dec 2000)

(Bradley, IGBP Newsletter 44, dec 2000)

LE FUTUR A L’ECHELLE GEOLOGIQUE Une prévision à base d’astronomie et de gaz à effet de serre

Période Glaciaire QUATERNAIRE HOLOCENE ANTHROPOCENE (P. Crutzen) Période chaude QUINTERNAIRE A. Berger, 2001

Développement Durable-Paleoclimat Les échelles de temps sont-elles comptatibles ? • Comprendre le comportement du système climatique dans une diversité suffisante de climats • Recher le(s) meilleur(s) analogue(s) possible(s) pour T et CO 2 • Etudier la stabilité des sites d’entreposage des déchets • Analyser les interactions possibles entre les impacts des activités humaines sur le climat des siècles à venir et les variations naturelles à l’échelle géologique. Notre responsabilité face à l’histoire de la Terre est-elle engagée ?

http: //www. climate; unibe. ch/gallery_co 2. html

14 kyr BP 0. 0167 | • ~80 kyr SS Aphelion • SS Perihelion 9 kyr BP 23° 4 • | 105 Wm-2 | 25 Wm-2 11 kyr BP | 9 kyr AP ~50 kyr ~20 kyr

Sustainable Development – Paleoclimate Are the time scales comptatible ? • To understand the behaviour of the climate system in a set of largely different climates • To find the best analogs for T and CO 2 • To study the stability of the repository sites for nuclear waste disposal • To analyse the possible interactions between impacts of human activities on the next centuries climate and the natural variations at the geological time scale. Is our responsability committed facing the Earth history ?