By Vincenzo Pascucci Dipartimento di Scienze Botaniche, Ecologiche é Geologiche. Universitá di Sassari pascucci@uniss.it Conferencia impartida en el marco de los viernes científicos de la Universidad de Almería

1. PAST-CLIMATE AS THE KEY TO
UNDERSTAND THE FUTURE:
EXAMPLE FROM THE MEDITERRANEAN SEA
VINCENZO PASCUCCI
DIPARTIMENTO DI SCIENZE BOTANICHE, ECOLOGICHE E
GEOLOGICHE
UNIVERSITA’ DI SASSARI
pascucci@uniss.it

2. Climate is changing?
Which are the evidences?
Is this a normal process?
Which have been recent past climatic changes?
Which has been their impact?
Can we say something?

3. PATHWAY…
- ACTUALISM
1. PRESENT CLIMAT
2. CAUSES OF CLIMATE CHANGE
- PAST
1. GEOLOGICAL EVIDENCES OF
CLIMATE CHANGES (SARDINIA)
- CLIMATIC CHANGES OF THE LAST 125 KY

4. WHAT INFLUENCE THE CLIMATE OF THE EARTH:
1. EARTH ORBIT AROUND THE SUN
yearly

5. p
C
L e
I r
M
A m
T a
I
C n
e
B
E n
L t
T
2. LATITUDE & ALTITUDE

6. 3. GREAT OCEAN CONVEYOR BELT
500 year to make the all circuit

7. WHAT INFLUENCE
CLIMATE CHANGES?
?

8. PLATE TECTONICS: long time
(millions of year = radical changes)

9. J
u
s
t
a
n
e
x
a
m
p
l
e

10. Orbital forces: short time
(thousand of years = long lasting changes)
today the Earth axis is 23°27’ inclined
Milankovitch
cycles

11. Sun spots (hundreds to tens of years 500-11y)
short time  climate changes = sensible
The change in the number of sunspots and in solar activity
(deduced from studies of carbon-14 concentrations in the wood of
tree rings and of beryllium-10 in ice cores) suggests that there
have been various exceptional periods of solar weakness during
the last millennium, namely, the Wolf (around 1300), Spoerer
(around 1500), Maunder (between 1645 and 1715) and Dalton
(1800-1830) periods.
These low points were most likely preceded by a period of
maximum solar activity, the Medieval Solar Maximum (between
1100 and 1250) (Jirikowic, 1994). According to some authors, a
similar maximum, the Contemporary Solar Maximum, is
occurring right now and is caused by a rise in the magnetic
activity of the solar corona during the 20th century (Lockwood,
1999). Basing their conclusions on models, some authors believe
that the solar activity of the last 70 years is the most intense of the
last 8,000 years (Solanki, 2004).
2009

13. EARTH TEMPERATURE

14. ANTARTICA & GREENLAND
ICE DRILLING PROJECT

15. EPICA & VOSTOK
(ice drilling project)

16. Main results are:
1. 8 glacial stages occurred during the last 740ky;
2. Interglacial past stages were as much warm as today;
3. Without human effect the present interglacial stage will last
other 15ky;
4. CO2 concentration is the highest of the last 444ky

17. What about CO2? Man has input more CO2
in the atmosphere in the
last 200y than the earth
system in 20ky… however
normally an increase of
CO2 into the system
precedes the beginning of
a glacial stage!!!!
CO2
T

18. Form Marine Isotopic Stages (MIS) to
Glacial and Interglacial stages: the last 300ky
…. Isotopic stages MIS (even=caluroso; odds=frio)…simple!!!

19. The present interglacial stage: the last 11ky

20. 1 warm every 1KY

21. Hannibal crosses the Alps with the elephants during the warm roman time

22. CLIMATE CHANGES OF THE LAST 1000 ANNI (ΔT = ±2 °C)
important changes every 500y

23. THE LAST 30y
ΔT = ± 0.774 °C
last coldest years 2007-08-09
(the most sensible to humans)

24. TOOLS TO PERFORM
PALEOCLIMATE STUDIES
• Sedimentology  paleoenvironments
• Stratigraphy  events order
• Geomorphology  processes
• Geochronology  time
• Geochemistry  past atmosphere vs present (i.e. δ
18/16O)

25. GEOLOGICAL ARCHIVES
• ANTARCTIC – GREENLAND (ICE)
• SARDINIA (ROCKS)
• ALPS (ROCKS & ICE)

26. ITALY  SARDINIA
Tectonically stable since Pliocene and in the Mid of the Mediterranean Sea

27. PAST GEOLOGICAL EVIDENCES OF CLIMATE CHANGES
SARDINIA (ITALY) WEST COAST
1. CAPO CACCIA CAVES

28. CAPO CACCIA SUBMERGED CAVES

29. CAPO CACCIA:
Partially submerged caves
sea level height reached about 125ky + 4m

30. -7m
Cervo Sardo bones (deer extinguished around
40-30ky) are found into speleothems

31. -7m
Cervo Sardo bones (deer extinguished around
40-30ky) are found into speleothems

32. SEA LEVEL MARKERS AND DEER BONES INDICATE THAT
CAPO CACCIA CAVES WHERE FLOODED BY SEA RISE
AROUND 125KY AND SUBSEQUENTLY EMERGED DUE TO
SEA LEVEL FALL

33. WEST SARDINIA: 2. prograding ancient beaches
SEDIMENTOLOGY

34. Detail: 2 relatively shallow water features
today some meters above sea level
2
1
ALGHERO

35. 3
2

36. 3
2 3
2

37. 3
2 3
23
paleosoil
2

38. OSL ages
dunes
3
2
Beaches and paleosoils

39. ….moreover, tropical warm fauna in beach deposits
STROMBUS
BUBONIUS

40. Additional items: 3. tidal notch and dunes
4. Tidal notch(s) +2/4m
DUNES

41. Things to remember
• 1-4 features:
– 1. fossiliferous/gravelly beach-shoreface (about
125ky);
– 2. silicoclastic beach (about 100ky);
– 3. dunes (about 77-47 ky);
– 4. tidal notch(s) partially covered by dunes (125-100
ky);

42. PAST GEOLOGICAL EVIDENCES OF CLIMATE CHANGES
SARDINIA (ITALY) EST COAST
CALA GONONE (OROSEI GULF)

43. FEATURES INDICATING SEA LEVEL CHANGES
1. OLD NOTCH(S) (4/8 m asl) MODERN NOTCH

44. 2. Bue Marino Cave aeolian sediments
Medium-coarse grained BUE 1 sample
bioclastic-rich sand, blown by the
wind into the cave from a marine
source (shelf/beach)
BUE 5 sample
BUE 2 sample

45. 2. BUE MARINO CAVE SEDIMENTS: AGES
BUE 1-5:
80-100KY
AL: Speleothem samples, BUE: sediment samples
1: Jurassic limestone; 2: clastic sediments; 3: Lithophaga boreholes
OSL age Clastic sedimentary infill pre-date the notch referred at 125ky

46. FEATURES INDICATING CLIMATE CHANGES:
3. COARSE ALLUVIAL FAN (dated at 45ky OSL)

47. 4. U-SHAPED VALLEY

48. 5. PERIGLACIAL DEPOSITS “ÉBULIS ORDONNÉ” (18-20 ky)

49. now forming as cryo-clastic processes in the alps…

50. Things to remember
• 1-4 features:
– 1. notch(s) (about 125ky) (sea level 4/6 m higher);
– 2. cave sediments (aeolian) (about 100-80 ky) (input
from an exposed sandy shelf during a relative sea
level fall) ;
– 3. coarse alluvial fan (about 40 ky);
– 4. u-shaped valley (no age data);
– 5. periglacial deposits (?18-20ky)

51. DATA INTERPRETATION

52. SEA LEVEL CHANGES
• 125ky (MIS 5) SL was at least +4m higher than today;
• Since 80ky (end of MIS 5) sea level started to fall;
• It reached the max of -130 bpsl about 20-18ky (MIS 2);
• From 17-11ky sea level raised very fast (end MIS2);
• We are in a highstand since 10ky (MIS 1) that should last for
other about 15ky (without human influence)

53. TEMPERATURES AND CLIMATE
• 125-95 ky (MIS 5e) temp was at least +2/4 °C higher than today
(subtropical climate and beaches formation). Apex of interglacial;
• 90-80ky (MIS 5a) temp cooled down (-3/4 °C lower than today,
soils formation) (warm and humid). End of interglacial;
• 60-45ky (MIS 4) temp was -6/8 °C lower than today (cryoclast, u-
shaped valley, exposure of shelf and dune formation) (cold and
humiddry);
• 45-20ky (MIS 3-2) temp was -8/10 °C lower than today (wide
cryoclast deposits and dune formation) (cold and very dry) Apex
of glacial

54. C
A
C
P
A
O
P
O
C
A
C
C
A
C
C
I
C
A
I
A
2
0
T
K
O
Y
D
A
A Y
G
O

55. C
A
C
P
A
O
P
O
C
A
C
C
A
C
C
I
C
A
I
A
2
0
T
K
O
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D
A
A Y
G
O

56. WHAT IS NEW?
1. SEA LEVEL CHANGES

57. SEA LEVEL FLUCTUATION DURING THE LAST
INTERGLACIAL 130-80 KY
(5 SUBSTAGES ABOUT 10KY EACH SEPARATED BY A
STRONG EROSIONAL UNCONFORMITY; 2 ASL, 1 BSL)
-bsl? +1m +4-6m

58. 10 ky cycles may be referred to:
• Subprecessional (or sub Milankovitch cycles);
– This short-time cycles can increase or decrease the
temperature of some degrees;
– At this moment it is not clear at all the origin of the
short-time cycles because very often they are non
linear and in cases they have been correlated to dust
aerosols present in the atmosphere);
– Solar irradiation variations;

59. Just an example: at the beginning of this interglacial,
in about 10 ky, the ice melted more or less completely.
This fast event is related to solar radiation changes.

60. SEA LEVEL RISE AFTER THE LGM (18KY)
…1 m rise every 100 years up to about 7/6ky, after that sea level
become more or less stable up to nowadays

61. …Y ITALIA SE CONVIRTIO’ EN BOTA!!!!
20ky ago In blu glaciers 6ky ago

62. Further studies
• Better characterize and explain the events occurred
during the last interglacial;
• Amount of dust in the past atmosphere;
• Solar irradiation variations (long and short time);
• Human impact on climate;
• Better understanding of the Atlantic Multidecadal
Oscillation (AMO) and if it existed also in the past (up
to now not older than 150y)….
• More money to geological research because our
future is written in the rocks and we only have
to find the way to dig it out!!!

63. Last example… thermal fluctuation of the
North Atlantic Ocean (AMO)
last 100 years
Mountain glaciers increase when AMO index is negative, and
retreat when AMO is positive

65. Forecast based on past (BLU LINE)
Forecast based on global warming idea (RED LINE)

66. So what is going on?
?

67. We will fire in the hellish earth!!!

68. …or we will die iced!!!

69. A possibility is also that someone is joking with us using
climate change as personal purpose to become famous!!!

70. ….but because
everybody wants
to speak about
climate…
GLOBAL WARMING EXPERCTS!!!
I did it too!!!!!!!

71. GRACIas
Le nuvole del cielo disegnano
la mia strada del ritorno,ma
solo tu raggio di sole sai quale
sia davvero.
Mi manca la tua luce, il tuo
calore, la tua bocca, il tuo
consiglio.
Questa notte solo naufragherò
tra i miei sogni dove spero di
incontrare la mia stella.
(Vince 07)