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Transcript of Land carbon cycle managed ecosystems and climate Galina Churkina Institute for Advanced...
Land carbon cycle managed ecosystems and climate
Galina Churkina
Institute for Advanced Sustainability Studies Potsdam, Germany
Outline
• Introduction: Role of land ecosystems in the global carbon cycle
• Drivers behind the European carbon sink
• Challenges in modeling of land ecosystems
Role of land ecosystems in the global carbon cycle
0
2
4
6
8
10
1950 1960 1970 1980 1990 2000 2010
year
Pg
C/y
r
Global anthropogenic emissions (CAntr)
0
2
4
6
8
10
1950 1960 1970 1980 1990 2000 2010
year
Pg
C/y
r
Global anthropogenic emissions (CAntr)
Remained in atmosphere (CAtm)
Absorbed by land and ocean
Airborne Fraction (AF) = CAtm/CAntr ~ 0.4 in 1950-2000
2005: Jones and Cox, JRL
Trend in AF after 2000 -?
Is AF increasing?
• Yes (Le Quere et al. Nature Geo, 2009)
• Earth’s carbon sinks are in decline
• No (Knorr, GRL, 2009, Francey et al. ICDC8, 2009)
• Earth’s carbon sinks are increasing proportionally to emissions
CAtm = CAntr - CLand- COcean
Crucial role in C uptakeUnderestimated ?
2009: Le Quere et al.,Nature Geo
(Statistics) (Model) (Model)
280
330
380
430
480
530
1860 1880 1900 1920 1940 1960 1980 2000 2020
Atmospheric CO2 Concentrations
(ice core)Observed (atmosphere)(ice core)Observed (atmosphere)(ice core)Observed (atmosphere) Management -?
Modeled with CLIMBER-BGC
2009: Churkina et al. GBC
Drivers behind the European carbon sinkChurkina et al. 2010, Biogeosciences
European ecosystems are a carbon sink of
~ 111±280 teragrams (Janssens et al. 2003)
~ 232±50 teragrams (Schulze et al. 2009)
Why Europe is a carbon sink?
Atmospheric deposition of
nitrogen
Regrowing forests/
abandment of croplands
Atmospheric deposition of nitrogen on land ecosystems of
Europe
2007: Dentener et al., GBC
2
3
4
5
6
7
8
9
10
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
year
Tg
/yr
0.1Tg/yr
0.03Tg/yr
Land cover conversion: Historical trends
2008: After Ramankutty et al., GBC
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010year
mln
sq
km crop+pasture
forest
grass
-6900sq km /yr 5800 sq km/yr
10100 sq km/yr -7000 sq km/yr
-3200 sq km/yr1100 sq km/yr
Surface Temperature of Europe
6
6.5
7
7.5
8
8.5
9
9.5
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
year
deg
C
0.02 degC/yr
0.01 degC/yr
2009: Chen et al., MPI-BGC Tech. Rep.
Atmospheric CO2
270
290
310
330
350
370
390
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
year
pp
m
1.11 ppm/yr
0.29 ppm/yr
After Etheridge et al, 1996 and Keeling & Whorf, 2005
Rates of change in environmental drivers accelerated in the second half of the 20th century
Land C balance and its drivers
C balance of Europe
ClimateAtmospheric CO2
and N deposition
Land Use (Conversion & Management)
Land Use Change
Land cover # 1
Land cover # 1*
Land cover # 2
(Change)
(Management)
(Conversion)
Although modification is not always detectable, it may have strong effect on carbon balance (forest management, fertilization, etc)
Land C balance and its drivers
C balance of Europe
ClimateAtmospheric CO2
and N deposition
Land Use (Conversion)
?
?
?
Vegetation models include:C, H2O cycles and
Land use change– JULES– ORCHIDEE
N cycle– BIOME-BGC– OCN
More details in:
2010: Churkina et al., Biogeosciences
One century of the European carbon balance
Atmospheric models: mean and uncertainty(2009:Schulze et al.)
Data compilation (2009: Schulze et al.)
European mean temperature
6
6.5
7
7.5
8
8.5
9
9.5
1950 1960 1970 1980 1990 2000 2010
ºC
OCN
Atmospheric CO2
300
310
320
330
340
350
360
370
380
390
1950 1960 1970 1980 1990 2000 2010
year
pp
m
OCN
Land cover conversion in Europe
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
1950 1960 1970 1980 1990 2000 2010
year
mln
sq
km crop+pasture
forest
grass
OCN
Nitrogen deposition in Europe
3
4
5
6
7
8
9
10
1950 1960 1970 1980 1990 2000 2010
year
Tg
/yr
OCN
OCN
Is response reasonable?
0
5
10
15
20
25
30
35
40
per
cen
t
Observed* JULES ORCHIDEE BIOME-BGC
OCN
* 2005: Ainsworth & Long, New Phyt.
NPP change in response to CO2 increase of 100 ppm
Is response reasonable?
0
5
10
15
20
25
30
per
cen
t
Observed* BIOME-BGC
OCN
* 2007: Elser et al. Ecol. Letters 2008: LeBauer & Treseder, Ecology
Modeled NPP change in response to N increase by 2-28
kgN/ha/yr
Obs. NPP change in response to N increase by 1-1000 kgN/ha/yr
Conclusions• European ecosystems are a C sink
because of interactions between• CO2 fertilization effect• Climate• N deposition • land cover conversion
• C sink is likely underestimated because models do not simulate interactions of LUC and abiotic changes
Challenges in land carbon sink estimates are related to …
Land Conversion
Land Management
Extent of land use change
Luyssaert et al., in preparation
Modeling of croplands
Gap between modeled and statistical yields of wheat. Averages for 1997-2003
Ma et al. sumbitted
ton per ha
Urbanization
?7.99 ? ?4.96
0
1000
2000
3000
4000
5000
6000Pr
imar
y en
ergy
cons
umpt
ion
Was
tetre
atm
ent
Land
fills
*
Proc
ess-
base
dCO
2-em
issi
onen
Impo
rted
elec
trici
ty
Exte
rnal
milk
prod
uctio
n*Ex
tern
alce
men
tpr
oduc
tion
Oth
ers
Soil
unde
rpe
rvio
us a
reas
Fore
st
Stre
et- a
ndpa
rk-tr
ees
Hum
anin
frast
ruct
ures
(bui
ldin
gs e
tc.)
Cse
ques
tratio
n
kt (C
O2-
)C
x
Carbon Cycle of Berlin 1
2 2 11 3 3
2
2
4
Data sources1 Federal Working Committee on Energy-Balances2 Berlin Senat 3 Statistics Agency Berlin-Brandenburg4 Tree inventories of Berlin‘s districts
Direct C release Indirect C release C storage C uptakeGottschalk et al., in preparation
Land-atmosphere feedbacks