Why has’not Earth warmed as much as expected?
Is the anthropocene an exceptional climatic era?
J.P. Rozelot
OCA - LAGRANGE (UMR 6525),
Nice-Sophia-Antipolis University,
BP 4 229, 06304 - NICE CEDEX 4, France
7th WORKSHOP ON LONG-TERM CHANGES AND TRENDS IN THE ATMOSPHERE
Buenos Aires, 2012
• A few historical considerations …
The collapse of the Classical Mayan civilization (800 AD – 1000 AD)
Mayan people, occupied Guatemala during the early pre-classical period
(2000 BC to 250 AD).
. This pre-classical period was followed by the major flowering of the Mayan
society, the Classical Period, from perhaps the 2nd century AD to the late 8th
century.
The Maya developed a system of writing, using elaborate symbols. Astronomy was
well developed and they had a very accurate calendar.
. The Mayans had entered a new period of partial ‘‘Collapse’’ called the Terminal
Classic (800 AD to 1000 AD). In 800 AD, before the ‘‘Collapse’’ it has been
estimated the population was about 3 million. By 1000 AD it was less than a
million or so. They finally disappear around 1100 AD.
Various causes have been suggested including foreign invasion, intercity warfare, soil
exhaustion, and revolt of the lower classes. All of these events appear to have taken
place at diverse places throughout the region during the collapse, but what was the
initiating cause?
The collapse of the Classical Mayan civilization (800 AD – 1000 AD)
A 2600-year climate history of the Yucatan Peninsula has been reconstructed from lake
sediments. These show a recurrent pattern of droughts with a dominant periodicity of
206 years (Hodell et al., 2001).
As noted by Haug et al. (2003) rapid expansion of the Maya from 550 to 750 AD took
place during a relatively wet period. However, from 750 to 950 the southern Maya
experienced devastating climate change, a generally dry period began about 760
AD. The dry period continued for about 140 years.
It was punctuated by a series of more severe multiyear droughts, about 760 AD,
810 AD, 860 AD, and 910 AD, which are shown in the detailed record of the rainfall
(Haug et al., 2003).
The relative dryness and periodic droughts undoubtedly put strains on the ability of
the people to sustain themselves. So, they disappeared or they migrated.
After Feynman, Advances in Space Research 40 (2007) 1173–1180
• A few years later, In Europe the Norse were leaving their
home territories and were marauding in Europe and
beyond.
• One of their first target (Erik the Red) was Greenland in
982 AD.
• Greenland colonies collapse in 1420.
• J. Ruzmaikin suggested they were responding to the
same widespread climate change as the Maya.
After Pulstil’nik, Sol. Physics, 2004
The Little Ice Age (LIA)
Max:
1410
1550 140 yr
1685 135 yr
1715
1870 155 yr
Smoothed values of the Winter Severity Index (after Van Engelen et al. 2001). The
Winter Severity Index values are expressed as departures from the 1501--1900 mean
and have been reversed, so that the most severe winters are indicated by negative
Values (See also Robinson, 2005).
800
900
1000
Severe floods
Maya Collapse
1050 and 1400
Medieval
Optimum
1530-1610 1600 and 1650
Wheat prices up
Deep Little Ice Age
982: Erik the Red 1420
(Greenland)
Greenland colonies
collapse
Does the severe climatic events are the ignition or the consequences
of the Earth’s temperature change ?
Cultural consequences
Historical studies of disasters continues to occupy a marginal position, but this is
slowly changing today.
Climatic scenarios do not have only to be built on present models, but have to take
into account past disasters, that cannot longer be regarded as single exceptional
cases. Deterministic models, as those used in GCM are useful. They are
unquestionably allowed and still permit to perform useful projections to help to take
right decisions.
But it would be of interest to link historical climatology and disaster studies,
as Christian Pfister wrote in his paper “Weeping in the Snow, the second period of
Little Ice Age-type impacts” [Pfister 2005].
But “the greatest obstacle continues to be a general suspicion of natural or climatic
determinism. Positing causal links between natural and socio-cultural facts is
considered a risky undertaking” as Erich Landsteiner has already mentioned in his
memoir ”Wenig Brot und saurer Wein” [Landsteiner 2005].
There has been impressive progress made over the last three decades in
reconstructing historical climate from well documentary sources.
• And to day …
Earth global warming
First semester
2012
2008
2008 Global Surface Temperature
(James Hansen, Makiko Sato, Reto Ruedy, Ken Lo)
Lower temperatures in 2008 than the
long term average.
What can be the cause?
- The Sun as a main driver
- Possible long term oscillations
Solar output and Earth’s Climate ?
05/10/2012
Solar output and Earth’s Climate ?
Climate sensitivity parameter λ,
∆TS = λ ∆F,
∆F : change in forcing at the top of the atmosphere (around 0.17 Wm-2),
ΤS : globally averaged surface temperature.
λ of the order of 0.5 K (W m−2)−1,
Conclusion: Earth’s global temperature to vary by a mere 0.09 K ≅ 1K
Observations indicate, at least regionally, larger solar-induced climate variations,
More complicated mechanisms are required:
Amplification retroactions (UTLS)
Long term oscillations (QBO)
Large EUV modulation
…
• Sensitivity of climate to cyclical variations in solar forcing will be higher for longer
cycles due to the thermal inertia of the oceans, which acts to damp high frequencies.
climate change is 1.5 times as sensitive to 22 year cyclical forcing relative to 11 year
cyclical forcing,
• Thermal inertia of the oceans induces a lag of approximately 2.2 (± 2) years in cyclic
climate response in the temperature data
Solar output and Earth’s Climate ?
Climate sensitivity parameter λ,
∆TS = λ ∆F,
∆F : change in forcing at the top of the atmosphere (around 0.17 Wm-2),
ΤS : globally averaged surface temperature.
λ of the order of 0.5 K (W m−2)−1,
Conclusion: Earth’s global temperature to vary by a mere 0.09 K ≅ 1K
Observations indicate, at least regionally, larger solar-induced climate variations,
More complicated mechanisms are required:
Amplification retroactions (UTLS)
Long term oscillations (QBO)
Large EUV modulation
…
• Sensitivity of climate to cyclical variations in solar forcing will be higher for longer
cycles due to the thermal inertia of the oceans, which acts to damp high frequencies.
climate change is 1.5 times as sensitive to 22 year cyclical forcing relative to 11 year
cyclical forcing,
• Thermal inertia of the oceans induces a lag of approximately 2.2 (± 2) years in cyclic
climate response in the temperature data
Where are the tilt-up points leading to a positive (negative) trend
of the current warming?
2.5 yr
Such sea level
decline is not
exceptional !
In southern hemisphere
the rate of sea-level
decline exceeded 40
millimeters per year
during MWP-1A
(began 14,650 years
ago ended before
14,310 years ago)
The sea level decline
was 14 m in 350 yrs.
Followed by an
Earth abrupt climate
change.
Pierre Deschamps, Nicolas Durand, Edouard Bard, Bruno Hamelin, Gilbert Camoin, Alexander L. Thomas,
Gideon M. Henderson, Jun’ichi Okuno & Yusuke Yokoyama
« Ice-sheet collapse and sea-level rise at the Bølling warming 14,600 years ago »
2 9 MA R C H 2 0 1 2 | VO L 4 8 3 | N AT U R E | 5 5 9
Solar output and Earth’s Climate ?
http://www.leif.org/research/TSI-SORCE-2008-now.png
Does the Sun recover its activity?
http://www.leif.org/research/TSI-SORCE-2008-now.png
•
Solar UV light is primarily
responsible for both
creation and destruction of
ozone in the Earth's
stratosphere and
mesosphere.
•
Solar irradiance varies by a
factor of 2 in the EUV !
Marchand, 2010
Penetration depth of the solar
radiation inside the atmosphere
UTLS
TSI reconstruction
• Taking into account
– 1/ the evolution of the
averaged magnetic flux from
decadal values of cosmogenic
isotope concentrations
recorded in natural archives
– 2/ a series of physics-based
models connecting the
processes from the
modulation of the cosmic ray
flux in the heliosphere to their
record in natural archives
It has been possible to
reconstruct the solar
irradiance back to the years 1000 and -8000 (i.e. BC).
Year BP(1950) Phi (MeV)
1000
900
800
700
600
500
400
300
200
100
0
-100
-2000
0
2000
4000
6000
8000
10000
Vonmoos, M.,Beer, J.,Muscheler, R., (2006) Large variations in Holocene solar activity – constraints from 10Be in
the GRIP ice core, J. Geophys. Res., 111, A10105
Steinhilber, F., J. Beer, (2008) Solar modulation during the Holocene,
Astrophys. Space Sci. Trans., 4, 1-6
Year BP(1950) Phi (MeV)
Reconstructions of the total solar irradiance
for the last 3000 years.
(Vieira et al, 2011)
All reconstructions are based on the
INTCAL04 ∆14C dataset, but employing
different reconstructions
of the geomagnetic dipole momentum. The
VADM reconstructions by Knudsen et al.
(2008) (KN08/blue line) and Genevey et al.
(2008) (GN08-8k/thin red line) are presented.
In addition, the VDM reconstructions by
Genevey et al. (2008)(GN08/green line) and
Korte & Constable (2005) (KC05/gray line)
are also plotted.
MCO
Deep LIA
Maya collapse
Reconstructions of the total solar irradiance
for the last 3000 years.
Greenland colonies
collapse
Helioclimatology
IMF strength
interstellar field line
heliopause
Ulysses
Balogh et al., 1995; Smith et al., 2001
|Br|
tic
p
i
l
ec
d
R
|BrE|
Ulysses showed
that everywhere
|Br|(d/R)2 = |BrE|
Earth
Thus total signed
magnetic flux
leaving the sun =
(1/2) x 4πR2 |BrE|
M.Lockwood@r l.ac.uk
05/10/2012
The variation of the strength of the interplanetary magnetic field increases by around
1900 to 1960 and since then is decreasing. As cycle 24 was « small »,
solar cycle average B will return to levels of around 100 years ago.
Do we enter a new blank era ?
Sun and climate
Some Key questions:
If I have time…
Otherwise skip
Is there possible long terme oscillations?
Anomaly
Anomaly (smoothed)
http://w w w .cru.uea.ac.uk/cru/data/temperature/
0,600
0,400
0,200
-0,400
-0,600
Years
05/10/2012
2011
2004
1997
1990
1983
1976
1969
1962
1955
1948
1941
1934
1927
1920
1913
1906
1899
1892
1885
1878
1871
1864
1857
-0,200
1850
0,000
Long term solar periodicites
Damon and Jirikovic (1992, 1994) have shown a recurrent period
at 211.5 and 88.1 yrs
in examining the production of 14C found in tree rings.
They pointed out that these two periodicities could also modulate the
Schwabe 11--yr period, and produce large periods of maxima and minima.
This yields a new « large » minium by about 2050-2060.
05/10/2012
0,900
80.0+
281.5+
Modulation
11,1 yrs,
88,1,
and 486.5
221,5years
modulation
in Tg
0,700
0,500
Tg
0,300
0,100
-0,100
-0,300
-0,500
-0,700
-0,900
1840
1860
1880
1900
1920
1940
Years
1960
1980
2000
2020
Do long term oscillations in the temperature of the Earth can be envisaged?
River Nile floods
See: A. Ruzmaikin, J. Feynman & Yuk Yung
Proceedings IAU Symposium No. 233, 2006
Do long term oscillations in the temperature of the Earth can be envisaged?
Data: Mémoire sur l’Histoire du Nil
by Prince Omar Toussoun (1925)
Conclusion (1)
1/ I do not pretend that all of the observed temperature variability is only due to TSI
variations in UV.
But up to date climate modesl must take it into consideration.
2/ The sum of the three components 11,1; 88,1 and 221,5 -i.e. nearly the Suess and the
Gleissberg cycles- seems, at least to first order, to fit the data.
This does not imply that the global warming in the last decades has been caused by
natural forcing factors alone, as models demonstrate. But natural periodic oscillations
(such as due to the Earth’s angular momentum changes) are not yet taken into account in
these models. So far very few groups have tackled these issues while more and more data
with high resolution are available.
3/ Various lines of evidence indicate that the solar wind magnetic field has a "floor" or
baseline state to which it falls when the sunspot number goes to zero for extended intervals
(several rotations).
Predction can be made: we are going, for the next solar cycles, towards a Great new
minimum.
Conclusion (2)
4/ TSI reconstruction shows that changes equivalent to these recorded today could have
occured in the past.
5/ Our findings underscore a need to improve scenarios for future climate change.
A history of studying possible connections between climatic impacts –or even
disasters– and the climate history must receive a new impulse.
6/ Extreme climate events must receive also a specific attention, as they can be
triggered by climate changes, or can be their echo. Such questioning highlights the need to
develop new initiatives in the field open by the title of this talk
i.e.: is the antropecene an exceptional climatic era?
Are we entering a new prolonged solar minimum ?
Thank You
o
v
e
R
n
o
i
t
lu
a
h
st
d
a
tm
e
h
et
h
t
r
a
E
An example of
the irradiance
(TSI) trend, left,
and Earth’s
temperature
trend, right,
during the years
1910-1945.
Combined Land and Marine
Temperatures trends versus Solar
Irradiance trends. Diamonds:
three independent periods of time: 18561910, 1910-1945 and 1946-1975. The
crossed squares represents (i) an other
independent set of data (1885-1940;
1941-1975) and (ii) two longer
(non-independent) segments (18561887; 1856-1975). The linear fit obtained
leads to a climatic sensitivity parameter
of = 0.46 C/Wm-2. The square point is
the estimate obtained for the 1976-2000
period of time.
The signature of the irradiance can be
retrieved, corresponding to the zero
ordinate of the regressive line.
Earth’s temperature long term variations T(t)
TE MP E R ATU R E IND E X
3.00
Ma unde r Minimum
2.00
1.00
-2.00
19
50
18
50
17
50
16
50
15
50
14
50
13
50
12
50
11
50
95
0
85
0
75
0
10
50
-1.00
65
0
55
0
0.00
Me die va l Optimum
-3.00
Ada pe d a nd up-da te d from W . D a ns ga a rd: 1984, "P a s t c lima te s " , R e ide l pub; C o., p. 228.
Sun and climate
Some Key questions:
Variability of the Solar Irradiance Over the Solar Cycle — How variable is
the Sun observed to be, and how does solar variability depend on
wavelength?
Atmospheric Models, Processes, and Solar Irradiance — Using results
from recent atmospheric measurements and associated model
improvements, what are the physical processes that modulate the middle
atmosphere and vertical coupling with lower atmospheric layers?
Models of Solar Processes Affecting Climate — What solar activity
features cause observed irradiance changes, how do these features
evolve on long time scales, and might such activity be forecasted?
Climate Models, Processes, and Solar Irradiance — How do current
global climate models parameterize responses to solar variations and
how do these parameterizations differ among the various models,
especially in accounting for the apparent sensitivity of Earth's
hydrological cycle to solar forcing.
05/10/2012
Thank You
o
v
e
R
n
o
i
t
lu
a
h
st
d
a
tm
e
h
et
h
t
r
a
E
Conclusion
In revisiting LIA and MWP, we show that the multi – centennial climate variability may be
larger than commonly thought, and that a part of this variability could result from a response
to (obviously) natural changes.
A large amplitude modulation of about 281.5 and 88.1yr -i.e. nearly the Suess and the
Gleissberg cycles- and 486.5 years can be retrieved from the data. This does not imply that
the global warming in the last decades has been caused by natural forcing factors alone, as
models demonstrate. But natural periodic oscillations (such as due to the Earth’s angular
momentum changes) are not yet taken into account in these models. So far very few groups
have tackled these issues while more and more data with high resolution are available.
An increase of sea level rise of greater amplitude that observed today has been recorded in
the past. This put a new look on the current conclusions.
Our findings underscore a need to improve scenarios for future climate change.
A history of studying possible connections between climatic impacts –or even disasters– and
the climate history must receive a new impulse.
Extreme climate events must receive also a specific attention, as they can be triggered by
climate changes, or can be their echo. Such questioning highlights the need to develop new
initiatives in the field open by the title of this talk.
(i.e. (Is the anthropocene era an exceptional climatic era?)
Sun and climate
The IMF is a vector quantity with three directional components, two of which (Bx and By) are
oriented parallel to the ecliptic. The third component--Bz--is perpendicular to the ecliptic and is
created by waves and other disturbances in the solar wind. When the IMF and geomagnetic
field lines are oriented opposite or "antiparallel" to each other, they can "merge" or
"reconnect," resulting in the transfer of energy, mass, and momentum from the solar wind flow
to magnetosphere The strongest coupling --with the most dramatic magnetospheric effects-occurs when the Bz component is oriented southward.
The
IMF is a weak field, varying in strength near the Earth from 1 to 37 nT, with an average
05/10/2012
value of ~6 nT.
Medieval Warm Period (MWP), or
Medieval Climatic Optimum (MCO)
•
Lasted from about 950 to 1250, during the European Middle Ages.
Less documented than the LIA, and more subject to uncertainties, several facts
permit to establish that the Earth’s temperature could have been roughly the same as
it was in the year 2000.
•
For instance, it is well known that the Vikings took advantage of ice–free seas in
Greenland to colonize lands of the far north.
•
A sediment core from the eastern Bransfield Basin, Antarctic Peninsula, identifies
large positive temperatures during the Medieval Warm Period [Khim et al. 2002]. Their
results show that temperatures derived from an 18O/16O profile through a stalagmite
found in a New Zealand cave (40.67S, 172.43E) suggested the Medieval Warm
Period have occurred between AD 1050 and 1400 and have been 0.75°C warmer
than the Current Warm Period.
•
The Medieval Warm Period has also been evidenced in New Zealand by an 1100–
year tree–ring record [Cook 2002].
•
Here also IPCC minimizes the climatic change: current evidence does not support
globally synchronous periods of anomalous cold or warmth over this time frame, and
the conventional terms of ’Little Ice Age’ and ’Medieval Warm Period’ appear to have
limited utility in describing trends in hemispheric or global mean temperature changes
in past centuries.
The Little Ice Age (LIA)
• This idiom was introduced as soon as 1939 by E. Matthes, in
relation with the position (advance or retreat) of glaciers in Europe. It
was latter on extended to a period of cooling ranging between 1550
and 1850. It is today admitted that this period spread over the
Northern hemisphere with a more intense cooler period between
1600 and 1650 (Macdougall 2004).
• IPCC has a restrictive and minimalist view on the question: the
“Little Ice Age” can only be considered as a modest cooling of the
Northern Hemisphere during this period of less than 1°C relative to
late 20th century levels.
• However, recent studies pointed out the existence of cold time
periods and climate changes in areas of the Southern Hemisphere
during the LIA, of more than the above-mentioned temperature.
Sun and climate
Some Key questions:
Variability of the Solar Irradiance Over the Solar Cycle — How variable is
the Sun observed to be, and how does solar variability depend on
wavelength?
Atmospheric Models, Processes, and Solar Irradiance — Using results
from recent atmospheric measurements and associated model
improvements, what are the physical processes that modulate the middle
atmosphere and vertical coupling with lower atmospheric layers?
Key role of the UTLS zone
Models of Solar Processes Affecting Climate — What solar activity
features cause observed irradiance changes, how do these features
evolve on long time scales, and might such activity be forecasted?
Climate Models, Processes, and Solar Irradiance — How do current
global climate models parameterize responses to solar variations and
how do these parameterizations differ among the various models,
especially in accounting for the apparent sensitivity of Earth's
05/10/2012
hydrological
cycle to solar forcing.
0,600
1998
2000
0,500
2008
0,400
0,300
2012 (1rst
0,200
trimester)
0,100
0,000
-0,100
1960 1965
1970 1975 1980
1985 1990 1995
-0,200
-0,300
-0,400
1996, 2000, 2008, 2012 tilt-up (<0) points?
2000 2005 2010
1996
Summary
•
Whatever mechanism caused past changes in the climate could perhaps be at
work today and in the future.
•
None of the natural or anthropogenic effects can alone explain the temperature
variations the last 150 years
•
The complexity of our atmosphere is a huge barrier.
– For instance - long term trends in cloud cover represents a huge challenge to
present and future global circulation models
•
We need to improve our knowledge about how indirect solar forcing may propagate
down to our climate system (influence of the UTLS zone)
•
Maybe there are other mechanisms that contribute and that we have not even
thought of!
What are the possible explanations?
Year
Tornadoes Hurricanes
Severe
Winter
Extreme
Precipitation
Events
Severe
droughts
Coastal
flooding
Heat waves
Others
Men activities
nb CME
2012
0
2
0
0
0
0
0
0
2
2011
3
1
0
0
1
0
0
0
5
2010
1
2
0
1
0
0
0
0
4
2009
0
0
0
1
0
1
0
1
3
2008
13
1
0
1
3
0
0
1
19
2007
1
0
0
0
4
3
0
0
8