The Global Carbon Balance and its Vulnerabilities

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Skee Houghton, unpublished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



deforestation




atmospheric CO2

deforestation




atmospheric CO2

deforestation


ocean sink


GCP 2006, in preparation

atmospheric CO2

deforestation


ocean sinkland sink



-2.2+ 0.5 PgC/yr - Oceans

-0.9+ 0.7 PgC/yr - Terrestrial

+4.1+ 0.2 PgC/yr - Atmosphere


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


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


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





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





Oceans

Land


>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





Oceans

Land


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:





Oceans

Land


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

Documents

The Global Carbon Balance and its Vulnerabilities