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The Global Carbon Balance and its Vulnerabilities
Pep CanadellGlobal Carbon ProjectInternational Project Office
CSIRO Marine and Atmospheric ResearchCanberra, Australia
Outline
1. Recent carbon-climate trends2. The global carbon budget3. Carbon source/sink processes4. Sink processes
• CO2 fertilization effect5. Source processes: vulnerabilities
• Drought• Soil respiration
Recent Carbon-Climate Trends: Signs of Trouble
UNESCO/Scope-GCP Policy Briefing, 2006; Canadell et al 2006, submitted
Fossil Fuel and Cement Emissions:
7.9 Pg C 0123456789
Foss
il Fu
el E
mis
sion
(GtC
/y Emissions1990 to 1999: 0.8% per year2000 to 2005: 3.2% per year
1850 1870 1890 1910 1930 1950 1970 1990 2010
280
300
320
340
360
380
400
Atm
oaph
eric
[CO
2] (p
pmv) [CO2]
2 ppm/year
Atmospheric CO2concentration:379 ppm
(36% above pre-industrial)
1980 to 1999: 1.5 ppm per year2000 to 2005: 2.0 ppm per year
1850 1870 1890 1910 1930 1950 1970 1990 2010
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1850 1870 1890 1910 1930 1950 1970 1990 2010
Tem
pera
ture
(deg
C)
Temperature 0.2 C/decade
Global Temperature:2nd-3rd hottest year
1st - 19882nd - 20023rd - 20054th - 20035th - 20046th - 2001
-0.200
0.000
0.200
0.400
0.600
0.800
1.000
1.200
1.400
1.600
1.80018
50
1860
1870
1880
1890
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
2000
AfricaLatin AmericaS. & SE Asia SUM
Skee Houghton, unpublished
Carbon Emissions from Tropical Deforestation2000-20051.5 Pg C yr-1
(18% total emissions)
Pg
C y
r-1Recent Carbon-Climate Trends: Signs of Trouble
Trajectory of Global Fossil Fuel Emissions
UNESCO/SCOPE-GCP Carbon Policy Brief 2006
0
2
4
6
8
10
12
14
16
18
1850 1900 1950 2000 2050 2100
Foss
il Fu
el E
mis
sion
(GtC
/yhistoric emissionsprojected emissions (A1B)to stabilise at 450 ppmto stabilise at 650 ppm
emissions gap
• Emissions scenario (eg SRES A1B): based on a storyline for global development• Stabilisation trajectory: an emissions consistent with stabilision at a given CO2 level
Anthrop. CO2 Emissions
Carbon-climate-human Interactions
Terrestrial & Ocean Biospheric C Sink
Atmospheric CO2
Temperature
deforestation
tropics
Global Carbon Budget (1850-2005)
Le Quere, GCP 2007, in preparation
deforestation
fossil fuel emissions
Global Carbon Budget (1850-2005)
Le Quere, GCP 2007, in preparation
deforestation
fossil fuel emissions
Global Carbon Budget (1850-2005)
Le Quere, GCP 2007, in preparation
atmospheric CO2
deforestation
fossil fuel emissions
Global Carbon Budget (1850-2005)
Le Quere, GCP 2007, in preparation
atmospheric CO2
deforestation
fossil fuel emissions
ocean sink
Global Carbon Budget (1850-2005)
GCP 2006, in preparation
atmospheric CO2
deforestation
fossil fuel emissions
ocean sinkland sink
Global Carbon Budget (1850-2005)
Le Quere, GCP 2007, in preparation
-2.2+ 0.5 PgC/yr - Oceans
-0.9+ 0.7 PgC/yr - Terrestrial
+4.1+ 0.2 PgC/yr - Atmosphere
Global Carbon Budget (2000-2005)
After IPCC-TAR 2001; Field and Raupach 2003, GCP, in preparation
+7.2+ 0.6 Pg C/yr
AnthropogenicEmissions (FF, cement)
Deforestation
+1.5 Pg C/yr – 2.4 +1.5 = -0.9
• Terrestrial and marine exchanges currently remove more than 4 Gt C yr-1 from the atmosphere (55% of anthropogenic emissions)
• This free service provided by the planet constitutes an effective 55% emissions reduction, worth Trillions of $$ per year if we had to provide it through mitigation measurements.
Biological Benefits
1. Are the sink mechanisms permanent features?
time
Sink
Stre
ngth
3. Will they saturate?
time
Sink
Stre
ngth
2. Will they increasein strength?
time
Sink
Stre
ngth
Carbon Sinks: How will they Behave in the Future
4. Will they disappear?
time
Sink
Stre
ngth
Carbon Sink Mechanisms (Globally and Australia)
Climate and Atmospheric Drivers:• CO2 fertilization and increased WUE• Nitrogen fertilization• NPP enhancement (or suppression) by climate change
Land Use Change Drivers:• Reforestation / Afforestation• Regrowth in abandoned agricultural land• Regrowth of previously disturbed forests (Fire, wind, insects, logging)• Woody encroachment on grassland/savannas• Forest thickening• Improved agriculture• Sediment burial• Decreased deforestation• Shifts in vegetation types• Wood products and landfills.
Carbon Source Mechanisms
• Deforestation• Wildfires• Insect attacks• Enhanced HR in warmer and wetter conditions• Soil depletion by agricultural practices• Permafrost thawing, thermokarst processes, C decomposition,
and vegetation dynamics• Peatland hydrology, drainage and C decomposition, and
vegetation dynamics
• Livestock methane production• Fossil fuel emissions
•
Climate Change Only
Friedlingstein et al, unpublished
Cumu
lative
NEP
(Gt)
Tropical Regions (30N-30S)
Climate Change + CO2 fertilization
Cumu
lative
NEP
(Gt)
~23% increased NPP at double CO2
The Importance of the CO2 Fertilization Effect
Fertilization Effect of 550 ppm of CO2 on Forest Productivity
Koerner 2006
Basal Area or Biomass
Saturation of CO2 Fertilization Effect
Relat
ive Y
ield %
(aCO
2/eCO
2
Wheat Yield
Plant BiomassLeaf C Assimilation
Canadell et al. 2007
Carbon Sinks from Forest Regrowth
Sink
0 30 60 90 120 150
0
2
4
-2C Si
nk S
treng
th (N
EP)
t4t1
t2
Years
Source
Biom
assAverage tree age in the US and Europe = 40-70 years
t3
Canadell et al. 2007
If the current terrestrial carbon sink…
… is largely driven by physiological responses(CO2 fertilization, N deposition)
Climate will warm as predicted
Sink
Stre
ngth
Present
…is largely driven by past and current land use
change(e.g., forest regrowth, thickening, woody
encroachment)
Climate will warm more rapidly than predicted
Sink
Stre
ngth
Present
Canadell et al. 2007
Vulnerability of the Carbon Cycle in the 21st Century
PermafrostHL PeatlandsT PeatlandsVeg.-Fire/LUC
CH4 HydratesBiological PumpSolubility Pump
Hot Spots of the Carbon-Climate System
Oceans
Land
Canadell et al. 2007Many Pools and Processes not included in Earth System models
Vulnerability of the Carbon Cycle in the 21st Century
PermafrostHL PeatlandsT PeatlandsVeg.-Fire/LUC
CH4 HydratesBiological PumpSolubility Pump
Hot Spots of the Carbon-Climate System
Oceans
Land
Field and Raupach 2004Canadell et al. 2006Many Pools and Processes not in included in Earth System models
>200 Pg C vegetation and soils vulnerable to drought x land use x fire
Mouillot et al. 2006
Trends in Carbon Emissions from Fires
2500
3000
3500
TgC yr -1total
200
600
1000
1400
1800
1905 1925 1945 2005
tropical savanna
tropical foresttemperate forest
boreal forest
1965
TgC yr -1
Angert et al. 2005
Drought Effects on the Mid-Latitude Carbon Sink
∂/ ∂t (NDVI): Summer 1982-1991
∂/ ∂t (NDVI): Summer 1994-2002
The largest productivity crash of the past 100 years
Ciais et al. 2005, Peylin et al., unpublished
The 2003 Heat Wave in Europe
30% Reduction of GPP0.5PgC Net source of CO24years Equivalent C sink
Mode
l NPP
gCm-2
mo
CO2 Anomaly
Drought related Emissions:0.2 PgC= 200 MtC= 730 Mt CO2
Compare with:
Australian GHG emissions (2002): 550 Mt CO2eqLess vigour More vigour
NDVI Anomaly - Monthly 1995-2004
Raupach et al, 2006, unpublished
95
96
97
98
99
01
00
02
03
04
Ning et al. 2006, submitted; Nepstad et al. 2006, in preparation
The 2005 Amazon Drought
• The lowest river stage in the 25 year data period for the upper Amazon
• 1 Pg C released (equivalent to the sink of the world’s tropics)
Drought-Carbon Emissions (1994-2005)
1997-98 SEA Tropical
1.4 PgC
01,02,03SEA Trop.1.2 PgC
1994-2002High-Mid LatitudeSummers undo the benefits of earlier spring
2003Europe0.5 PgC
2002-present0.2 Pg C
2003Siberia0.2 PgC
1997 AmazonFire Year 2005
Amazon1 Pg C
Canadell 2007, in preparation
Vulnerability of the Carbon Cycle in the 21st Century
PermafrostHL PeatlandsT PeatlandsVeg.-Fire/LUC
CH4 HydratesBiological PumpSolubility Pump
Hot Spots of the Carbon-Climate System
Oceans
Land
Field and Raupach 2004Canadell et al. 2006Many Pools and Processes not in included in Earth System models
>500 Pg C - frozen sedimentsvulnerable to warming(yedomas in Siberia)
400 Pg C - frozen soilsvulnerable to warming
Permafrost Degradation in the 21st Century
2100 extension: 1 Million km2
Present extension: 10.5 Million km2
Lawrence et al. 2005, Gruber et al. 2004
Carbon Emissions from thawing permafrost by 2100: 100 Pg C
Vulnerability of the Carbon Cycle in the 21st Century
PermafrostHL PeatlandsT PeatlandsVeg.-Fire/LUC
CH4 HydratesBiological PumpSolubility Pump
Hot Spots of the Carbon-Climate System
Oceans
Land
Field and Raupach 2004Canadell et al. 2006Many Pools and Processes not in included in Earth System models
Pho
toP
hoto
: Erk
ki O
ksan
en: E
rkki
Oks
anen
10,000 Pg C – gas hydrates in frozen ground and ocean sediments
Beauchamp 2004
Occurrence: Beneath oceans and in polar regions
• Continental permafrost: is unlikely to be disturbed by surface warming by the end of this century• Deep ocean deposits unlikely to be disturbed by surface warming and pressure changes• Surprises? : Outburst of gas due to build up of pressure in the sediments
Carbon content
The Vulnerability of Methane Hydrates
If they contain enough natural gas, they will be exploited during the 21st century adding a new carbon source to the Fossil Fuel energy mix that can last for centuries.
Biggest threat to climate:
Vulnerability of the Carbon Cycle in the 21st Century
PermafrostHL PeatlandsT PeatlandsVeg.-Fire/LUC
CH4 HydratesBiological PumpSolubility Pump
Hot Spots of the Carbon-Climate System
Oceans
Land
Field and Raupach 2004Canadell et al. 2006Many Pools and Processes not in included in Earth System models
Pho
toP
hoto
: Erk
ki O
ksan
en: E
rkki
Oks
anen
400 Pg C – cold peatlandsvulnerable to climate change
100 Pg C – tropical peatlands vulnerable to land use and
climate change
Takashi Hirone
Worm
GWL9305
Ground water level modulates the intensity and spread of fires in the tropical peat swamp forest
0
50
100
150
200
250
1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004
-200
-150
-100
-50
0
50
no
Plot Plot 1B Camp Plot 1B
no data
Prec
ipitat
ion (m
m da
y-1)
Grou
nd W
ater L
evel
(cm)
no data
Takahashi, 2006, unpublished
South Kalimantan
Big Fire Year Fire Year No Fire
40 km
40 km
Fire occurrence on Borneo 1997-2004
0
1000000
2000000
3000000
4000000
5000000
6000000
7000000
1997 1998 1999 2000 2001 2002 2003 2004
Sum: 22 Million ha (22,950.949 ha)33% burned more than once
MODIS hotspots: courtesy of MODIS fire teamNOAA AVHRR: courtesy of IFFM, JAICA
ATSR: courtesy of ESA
MODIS Hotspots
Source/Sink Dynamics of Drained Peatland Forests
Takashi 2007, in press
CO2 sourceCO2 sink
Dec. Jun. Dec. Jun. Dec. Jun. Dec.
-2
0
2
4
6
Time
2002 2003 2004
Net E
cosy
stem
Exch
ange
(g C
m2
d-1) South Kalimantan, Borneo
• Sink: CO2 fertilization• Source: Heterotrophic respiration
• Nitrogen fertilization and limitation (and P)• Wildfires• Regrowth (age structure)• Shifts in vegetation types• Land use and Cropland management• Permafrost thawing, C decomposition, vegetation dynamics• Peatland drainage, C decomposition, vegetation dynamics
How many of the carbon sink/sources processes are part of Earth System models?
Anthropogenic Carbon Emissions
Up to250 ppm
IPCC SRES 2000; Friedlingstein et al. 2006
Vulnerability of the Carbon Cycle in the 21st century
Up to200 ppm
Biospheric-Carbon-Climate Feedback
www.globalcarbonproject.org