CarboEurope Results:Vulnerability of Carbon Sink

by Climate Change

ChairmanHan DolmanAlterra, Wageningen, The Netherlands

European OfficeAnnette FreibauerMax-Planck-Institute for Biogeochemistry,Jena, Germany

http://www.bgc-jena.mpg.de/public/carboeur/

Ciais et al.

West European land uptake:NAO linked?

ECCP Working Group Research, Subgroup SinksStockholm Meeting: Sinks in Europe

Forest Grassland Arable Land Wetland

Area (Mio ha) 130 76 73 19

C stock (Pg) 6.8 ? 3.86 13.1

Sink (Pg/y) 0.1-0.7 ? 0 0.004-0.01

Other GHGs source? source source source!

Freeze/Thaw and Ice Affected Regions(Global Freezing Index)

Approximate distribution of frost and ice affected regions (i.e. areas with a freezing index > 0).Global freezing index is defined as the cumulative number of degree-days with air temperatures below 0 °C as determined from long-term (1920 - 1980) mean monthly global surface air temperatures. (Source: Legates and Willmott 1990, courtesy of NSIDC).

0

20795

0

30

60

90

30

60

90

Boreal Spring Freeze-Thaw Transition Events

from: Running, Way, McDonald, Kimball, Frolking, Keyser and Zimmermann EOS Trans. AGU (1999)

Growing season lengthcritical in boreal systems

Example: Northern Finland

Simulated daily net carbon exchange (NEE) accumulation withina mature boreal Picea mariana (black spruce) stand in central Manitoba, Canada

(after Frolking et al. 1996).

Inter-Annual Variability of Net Carbon Ecosystem Exchange in a Boreal Picea

mariana Stand

Year

1995 1996 1997 1998 1999

CO

2 f

lux

(to

n C

ha-1

yr-1

)

0

2

4

6

8

10

12

14

16

NEE Respiration Assimilation

Interannual variability in NEE in temperate coniferous forest driven by NPP?

Example: Scots Pine in NL

1

3

5

7

9

11

13

2/9

63

/96

4/9

65

/96

6/9

67

/96

8/9

69

/96

10

/96

11

/96

12

/96

12

/96

1/9

73

/97

3/9

74

/97

5/9

76

/97

7/9

78

/97

9/9

71

0/9

71

1/9

71

2/9

71

/98

2/9

83

/98

4/9

85

/98

6/9

87

/98

8/9

8

9/9

81

0/9

81

1/9

81

2/9

8

date

C

O 2 s

oil

effl

ux

(m

ol m

-2se

c-1)

0

5

10

15

20

25

30

so

il m

ois

ture

(%

Vo

l.)

,so

il t

em

pe

ratu

re(°

C)

Sresp

RH soil

T soil

Mediterranean forest: NEE driven by drought limitation Mediterranean forest: NEE driven by drought limitation of soil respiration?of soil respiration?Example: Soil respiration for Q. ilex forest 1996 - 1998Example: Soil respiration for Q. ilex forest 1996 - 1998

Carbon sink indicators:

• Biome-specific change in C stocks and C fluxes• Separate indicators for soil and biomass

• Boreal regions: vulnerability of soil C through temperature riseenhanced NPP through longer growing seasonrisk of high CH4 release from warming wetlands

• Temperate regions: vulnerability of NPP to extreme eventsvulnerability of NPP by drought spells

• Mediterranean regions: drought limitation of soil respirationvulnerability of C stocks by drought and fire