Transcript No Slide Title

The carbon cycle and the Anthropocene
Michael Raupach1,2
1Centre
for Atmospheric, Weather and Climate Research,
CSIRO Marine and Atmospheric Research, Canberra, Australia
2ESSP
Global Carbon Project
Thanks:
Pep Canadell, Philippe Ciais, Ian Enting, John Finnigan, Pierre Friedlingstein,
Corinne Le Quéré, David Newth, Glen Peters, Peter Rayner, Cathy Trudinger,
and many more GCP and CSIRO colleagues
"Earth System Science 2010: Global Change, Climate and People", 10-13 May 2010, Edinburgh, UK
Outline

The carbon cycle as a progenitor of the Anthropcene

The contemporary carbon cycle
• CO2 emissions trajectories
• Partitioning anthropogenic CO2 to air, land and ocean

Stabilising the carbon-climate-human system
• sharing a cumulative global quota on CO2 emissions
The carbon cycle as a progenitor
of the Anthropocene

The biosphere
• A complex adaptive system based on carbon
• Evolving for 3.5 billion years

The anthroposphere
• One species finds a new evolutionary trick: use of exosomatic energy
• Easiest energy source: detrital carbon from the biosphere
• Evolving for tens of thousands of years
• Biologically based, with extra technological, social, cultural levels

Since 1800, global
per-capita wealth and
resource use have
doubled every 45 years
 Growth
obal population
andrates
GDP

This exponential growth is
the dominant instability in
the earth system
100000
Global population and GDP
Population
Population (million)
GDPppp
GWP (billion Y2000 $US
/ y)
10000
1000
100
10000 0
Per capita GDPppp ($/person)
•
•
•
lation
ppp
(1860-2010)
Population: 1.3 %/y
GWP:
2.8 %/y
GWP/Pop: 1.5 %/y
Population (million), GDPppp ($billion)
A phase transition
in human ecology
500
1000
Global
per capita 1500
GDP
2000
GWP per capita
(Y2000 $US / person / y)
1000
doubling
time = 45 y
100
Angus Maddison
1000
1500
(http://www.ggdc.net/maddison/)
2000
AD
0 0
500
500
1000
1000
1500
1500
2000
2000
Outline

The carbon cycle as a progenitor of the Anthropcene

The contemporary carbon cycle
• CO2 emissions trajectories
• Partitioning anthropogenic CO2 to air, land and ocean

Stabilising the carbon-climate-human system
• sharing a cumulative global quota on CO2 emissions
Le Quere et al. (2007)
Nature Geoscience
The carbon cycle since 1850
2000-2008
(PgC y−1)
other industrial
emissions
8
CO2 flux (PgC y−1)
6
4
2
fossil fuel
emissions
tropical
nontropical
deforestation
0
7.7
1.4
atmospheric CO2
−2
4.1
−4
land
−6
ocean
−8
1850
3.0 (5 models)
2.3 (4 models)
1900
1950
2000
0.3 Residual
Global CO2 emissions

Fossil fuels:
• 2007 emission 8.5 PgC
• 2008 emission 8.7 PgC
• 2000-08 growth: 3.4 % y1
Fossil Fuel Emission (GtC/y)
30
25
20
15
10
5
0
1850

Land use change:
• 2007 emission ~1.5 PgC
• 2000-07 growth: ~0 % y1
Without extra change in C
intensity, GFC will "save" about
0.25 ppm CO2 increase
10
9.5
Fossil Fuel Emission (GtC/y)

CDIAC
IEAall
A1B(Av)
A1FI(Av)
A1T(Av)
A2(Av)
B1(Av)
B2(Av)
9
8.5
8
7.5
1900
1950
2000
2050
2100
2000
2005
2010
2015
CDIAC
IEAall
A1B(Av)
A1FI(Av)
A1T(Av)
A2(Av)
B1(Av)
B2(Av)
Projection
7
6.5
6
5.5
Graphs: Raupach et al. (2007) PNAS,
with updated data: CDIAC to 2007, IEA to 2006
5
1990
1995
Raupach and Canadell (2010) COSUST
4
b
d
2
a
1
0
1990
2010
2030
-1
30
-2
-3
-4
l Emission (GtC/y)
Growth rate of fossil-fuel CO2
CO2 emission
emission (%/y)
(%/y)
3
Emissions growth rates:
SRES and observations
c
25
Observed growth rates
a: 1990-99
b: 2000-05 20
c: 2000-07
d: 2000-10 15
SRES scenarios
dashed
= marker
CDIAC
solid = family
IEAall average
A1B(Av)
A1FI(Av)
A1T(Av)
A2(Av)
B1(Av)
B2(Av)
2050
2070
2090
Raupach et al. (2007) PNAS
Updated with IEA data to 2006
Drivers of global emissions

Kaya Identity
G
F
F  P 

P
G
1.5
1.4
World
1.3
1.2
Fossil-fuel CO2
emission
Population
Per-capita GDP
Carbon intensity
of GDP
1.1
1
0.9
0.8
0.7
0.6
0.5
1980
F (emissions)
P (population)
g = G/P
h = F/G
1990
2000
2010
Outline

The carbon cycle as a progenitor of the Anthropcene

The contemporary carbon cycle
• CO2 emissions trajectories
• Partitioning anthropogenic CO2 to air, land and ocean

Stabilising the carbon-climate-human system
• sharing a cumulative global quota on CO2 emissions
Allen et al. (2009, Nature)
Cumulative CO2 emissions
as a measure of climate forcing
15002000
530
Past
FF reserves
>3000?
Unconventional
Peak warming from preindustrial (degC)
A2
A1FI
A1B
B2
A1T
B1
0
1000
2000
3000
4000
Q = cumulative CO2 emissions from preindustrial (PgC)
5000

Plot against time
2000
1500
1000
Peaks in emissions,
CO2 and temperature
occur progressively
later
Emissions
3000
2500
ΔT [degK]

Total emissions
quota Q(∞) [PgC]
CO2 [ppm]
Trajectories of
CO2 and T
CO2
Temperature
Time [years]

Plot against Q(t)
= cumulative emissions
to time t)
CO2 [ppm]
Trajectories of
CO2 and T
3000
2500
2000
1500
Total emissions
quota Q(∞) [PgC]
1000

Peak T is a nearly
linear function of Q to
time of peak
"Committed warming"
becomes the warming
between times of peak
emissions and peak
temperature
3000
ΔT [degK]

2500
2000
1500
NOW
1000
Cumulative emission Q(t) [PgC]
After Allen et al. (2009, Nature)
Cumulative emission targets and climate risk
Peak warming above preindustrial (oC)
Past emissions
Conventional fossil C reserves
Unconventional reserves
0.9
0.8
0.7
0.6
0.5
Probability of
avoiding peak
warming
Cumulative emissions (billion tonnes C)
The tragedy of the commons
 and beyond

Hardin (1968) - parable and lack of technical fix

Pretty (2003):
• social capital as a prerequisite for collective
resource management
• 5 kinds of capital:
natural, physical, financial, human, social

Dietz, Ostrom and Stern (2003):
• Adaptive governance in complex systems
• Emerges if there are ways to:
√
• Provide information
x
• Deal with conflict
• Induce rule compliance x
• Provide infrastructure x
• Be ready for change x
Hardin G (1968) The
tragedy of the commons.
Science 162, 1243.
Dietz T, Ostrom E, Stern
PC (2003) The struggle
to govern the commons.
Science 302.
Pretty J (2003) Social
capital and the collective
mangement of resources.
Science 302.
Reprinted in Kennedy D
et al. (2006) Science
Magazine's State of the
Planet 2006-2007. Island
Press, Washington DC.
Trajectories for capped CO2 emissions

Emissions trajectory is
specified by long-term
exponential decay at
specified mitigation
rate m

OR specified cap on
all-time cumulative
emissions Q∞:
Q  
 F t  dt
all
time

There is a 1:1 mapping
between m and Q∞
Q∞
m
Emission
[PgC/y]
Total emissions
quota Q∞ [PgC]
FF
530 PgC to 2008
(FF+LUC)
LUC
3000
2500
2000
1500
1000
Summary

The carbon cycle as a progenitor of the Anthropcene
• A key enabler of the Anthropocene is the use of exosomatic energy
• The primary energy source was, and remains, detrital biotic carbon

The contemporary carbon cycle
• Fossil-fuel CO2 emissions have accelerated
• Partition fractions of anthropogenic CO2 to air, land and ocean have
been nearly constant, because emissions have grown nearly
exponentially and the C cycle has been nearly linear
• The total CO2 sink rate is decreasing, mainly through the ocean sink

Stabilising the carbon-climate-human system
• The task is to share a cumulative global quota on CO2 emissions
• Full equity (population sharing) is not possible
Attribution of historic emissions is not possible
• The most achievable sharing rule common to all major nations goes
about 70% towards full equity