Climate warming 'backward - The last 100 Million years Transitions from Greenhouse to Icehouse Climate
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Climate warming `backward´
The last 100 Million years
Transitions from Greenhouse to Icehouse Climate
Climate System II
Gerrit Lohmann
with Christian Stepanek
Glacial-Interglacial variability
Global Sea
Level [m]
(Bintanja et al.,
2005)
CO2
[ppmv]
From ice cores
(EPICA, 2009)
Temp. anomaly
“O-18”
[°C]
al
ci
al
la
i
rg
c
la
te
Million years G
In
Glacial-Interglacial variability
Global Sea
Level [m]
(Rohling et al.,
2009)
CO2
[ppmv]
From ice cores
(EPICA, 2009)
Temp. anomaly
“O-18”
[°C]
Million years
ther
0
0
0.0 0.1 0.2 0.3 0.4
0.0 0.1 0.2 0.3 0.4
halosteric SLR [m]
Natural variability and perturbed climate
(b)
0.0 0.1 0.2 0.3 0.4
0.0 0.1 0.2 0.3 0.4
halosteric SLR [m]
(b)
deep paleo glacial-interglacial present, future
4
4
4
totalsteric SLR [m]
(c)
4
4
totalsteric SLR [m]
(c)
Global Sea
3
3
2 m
3
3
2
2
2
2
Level [m]
1
1
1
1
0
0
0
0
0
1800 1900 2000 2100 2200 2300 2400 2500
1800 1900 2000 2100Year
2200 2300 2400 2500
Year
Figure 5 global mean sea level change (m) contributed from (a) thermo steric, (b) halosteric and (c
Figure 5 global mean sea level change (m) contributed from (a) thermo steric, (b) halosteric and
total steric.
total steric.
RCP8.5
Scenarios
CO2 RCP6
[ppmv] RCP4.5
RCP3-PD
COSMOS+ISM
Temp. anom.
“O-18”
[°C]
Million years year
(Kominz et al., 2008; Pagani et al., 2009; Kramer et al., 2011; Crowley & Kim 1995, Wei & Lohmann,)
Sea level: 10 ky BP
O-18 and sea level
Transitions from Greenhouse to Icehouse Climate:
Evidence from Marine Sediments
Das Bild kann nicht
angezeigt werden.
NH ice sheet
Antarctic ice sheet Integrative approach
Data-Modelling
Proxy estimates of atmospheric
Global deep-sea O-18 pCO2 (Pearson & Palmer 2000; Pagani et al.
(Zachos et al. 2001)
1999, 2005)
Transitions from Greenhouse to Icehouse Climate:
Evidence from Marine Sediments
Das Bild kann nicht
angezeigt werden.
NH ice sheet Miocene
Antarctic ice sheet
Proxy estimates of atmospheric
Global deep-sea O-18 pCO2 (Pearson & Palmer 2000; Pagani et al.
(Zachos et al. 2001)
1999, 2005)
Transitions from Greenhouse to Icehouse Climate:
Evidences from Marine Sediments
Das Bild kann nicht
angezeigt werden.
NH ice sheet Miocene
Eocene/Oligocene
Antarctic ice sheet
• Eocene long-term climate cooling
• Eocene/Oligocene glaciation of Antarctica; drop in pCO2
• Compare to the Miocene/Pliocene cooling; low pCO2
Proxy estimates of atmospheric
Global deep-sea O-18 pCO2 (Pearson & Palmer 2000; Pagani et al.
(Zachos et al. 2001)
1999, 2005)
Climate warming `backward´
Climate warming `backward´
1000Flat Temperature Gradient
Present Day
Late Miocene
Crowley
Steppuhn et al., 2006
Reason? Many authorsEnergy Budget
• In steady state, energy
follows energy balance
model:
CHANGE IN STORAGE = IN – OUT
• many papers discuss an
imbalance in this equation,
which results in missing
energy
(Trenberth & Fasullo, 2012)Northward Heat Transport
Global meridional heat transport divides roughly equally into 3 modes:
1. atmosphere (dry static energy)
2. ocean (sensible heat)
3. water vapor/latent heat transport
The three modes of poleward transport are comparable in amplitude, and distinct in character
(sensible heat flux divergence focused in tropics, latent heat flux divergence focus in the
subtropics)
(residual method,
TOA radiation
1985-89 and
ECMWF/NMC
atmos obs)
90S 90NFlat Temperature Gradient
Present Day
Late Miocene
Crowley
Steppuhn et al., 2006
Reason? Many authors
Ø Sensible heat transport
Ø Latent heat transport
Ø Ocean heat transport
Ø Orography Greenland: high latitude warming
Ø Changes in the land surface cover
Ø Other effects?Flat Temperature Gradient
Present Day
Late Miocene
Crowley
Steppuhn et al., 2006
Reason? Many authors
Ø Sensible heat transport ~ DT EBMs, ……
Ø Latent heat transport ~ ¶q
DT ¶T Caballero & Langen
Ø Ocean heat transport Panama Gateway, Atlantic salinity reduction
Ø Orography Greenland: high latitude warming
Ø Changes in the land surface cover
Ø Other effects?Our current warming
boring for the hundredth time
Energy Budget
CHANGE IN STORAGE = IN – OUT
• many papers discuss an
imbalance in this equation,
which results in missing
energy
(Trenberth & Fasullo, 2012)Fanning and Weaver, 1996; Lohmann and Gerdes, 1998) to study the fee
the atmosphere-ocean-sea ice system. One of the most useful examples of
but powerful, model is the one-/zero-dimensional energy balance model. As
Energy balance model
point, a zero-dimensional model of the radiative equilibrium of the Earth is i
(Fig. 1)
Temperatures from EBMs: the e↵ective heat capacity matters 10
2 2 4
(1 ↵)S⇡R = 4⇡R ✏ T
where the left hand side represents the incoming energy from the Sun (size of
shadow area ⇡R2 ) while the right hand side represents the outgoing energy
Earth (Fig. 1). T is calculated from the Stefan-Boltzmann law assuming a
radiative temperature, S is the solar constant - the incoming solar radiation
area– about 1367W m 2 , ↵ is the Earth’s average planetary albedo, measu
0.3. R is Earth’s radius = 6.371 ⇥ 106 m, is the Stefan-Boltzmann co
5.67 ⇥ 10 8 JK 4 m 2 s 1 , and ✏ is the e↵ective emissivity of Earth (about 0.
Archer, 2010). The geometrical constant ⇡R2 can be factored out, giving
(1 ↵)S = 4✏ T 4
Solving for the temperature,
s
4 (1 ↵)S
T =
4✏
Figure 1. Schematic view of the energy absorbed and emitted by the Earth following
(1). Modified after Goose (2015).
Since the use of the e↵ective emissivity ✏ in (1) already accounts for the g
e↵ect we gain an average Earth temperature of 288 K (15 C), very close to
boring for the hundredth
temperature observations/reconstructions (Hansen ettime, but …
al., 2011) at 14 C for 1As a logical next Equation
step, let us (10)
now include an the
shall be expl
20 diffusion which has
Cp @t T = r · HT + (1 ↵)S(', t) ✏ T been
4
. p
Temperatures from EBMs: the e↵ective heat capacity matters 13
with S(', t) being 1975a,b). In the
calculated daily following
(Berger and L
coefficient k = 1.5 ·latitude
106 m2 /sisunder
HT present
= krT .O
orbita
15 for large heat capacities. Furthermore, the mean tem
Cp @t T = r · HT + (1
at high latitudes (for latitudes polewards of ' = 5
with moderate warming at low latitudes
numerically. (dashed c
The boundary
hand side in the
25 energy balance
1975a,b; equations,
Stocker both
et al., 199f
Figure 4. Equilibrium temperature of (15) using di↵erent di↵usion coefficients. The
blue lines use 1.5 · 106 m2 /s with no tilt (solid line), a tilt of 23.5 (dotted line), and
as the dashed line a tilt of 23.5 and ice-albedo feedback using the respresentation of
Sellers (1969). Except for the dashed line, the global mean values are identical to the
budget. In both considered cases, at strong diurna
value calculated in (12). Units are C.
different values of k (solid
In the exercise, long-wave radiation as A + BT
20 the seasonal amplitude for the Cp -scenarios as in✏
1 Z⇡/2
(1 ↵)S cos ' cos ⇥
EBM
ulate the zonal mean of (6) by integration at the latitudinal cycles we have
s
4
T (') = d⇥
2⇡ ✏
⇡/2
p ⇡/2 s
Z
2 4 (1 ↵)S
= (cos ⇥)1/4 d⇥ (cos ')1/4
2⇡ 4✏
⇡/2
| {z }
2.700
s
4 (1 ↵)S
= 0.608 · (cos ')1/4 (7)
4✏
tion on latitude (Fig. 2). When we integrate this over the latitudes, we obtain
⇡/2
Z
1
T = T (') cos ' d'
2
⇡/2
s ⇡/2
Z
0.608 4 (1 ↵)S
= · (cos ')5/4 d' Figure 2. Latitudinal temperatures of the EBM with zero heat capacity (7) in cyan
2 4✏ (its mean as a dashed line), the global approach (3) as solid black line, and the zonal
⇡/2
| {z } Heat capacity of the climate system
and time averaging (11) in red. The dashed brownish curve shows the numerical
solution by taking the zonal mean of (9).
1.862
s s
p 4 (1 ↵)S 4 (1 ↵)S Fast rotation
= 0.4 2 = 0.566 (8)
4✏ 4✏
e, T = 163K is a factor 0.566 lower than 288 K Lohmann,
as stated at (1). The standard
2020
https://esd.copernicus.org/articles/11/1195/2020/esd-11-1195-2020.pdf
Fig. 1 has imprinted into our thoughts and lectures. We should therefore bePractical Jan 11, 2022 Exercise EBM analysis • https://1drv.ms/u/s!AnZSDMNwdkDMgccDeu hjFFrmQHaqvw?e=ZaHqPA • https://1drv.ms/u/s!AnZSDMNwdkDMgbx6sr 3gVubSIqlYVw?e=MacPeK
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