Johannes LehmannDepartment of Crop and Soil SciencesCornell University
Biochar and Mitigation of Climate Change
Biochar System – Core Principle
Lehmann, 2007, Frontiers in Ecology and the Environment 7, 381-387
Biochar and Climate Change Mitigation
Lehmann, 2007, Nature 447, 143-144
Natural Occurrence
Biochar Abundance in World Soils
Krull et al, 2008, in: Nova Sci Publ
(World Soils Archive of ISRIC)
Biochar Abundance in Soils
NSA Lead ProfilesQLD TransectDWN TransectMajor Australian CitiesKatherineDaly Waters
0
5
10
15
20
25
30
35
10203040506070 80 90100 NSA (N=58)QLD (N=114)
DWN (N=280)
N
umbe
r of s
oils
(% o
f all
test
ed s
oils
)
Black Carbon (% of total organic C)
Average≈20%(n=452)
34Gt SOC (0-1m)(Grace et al., 2006, Carbon Balance and Management 1,14)
20% ≈ 7Gt0.1Gt CE /yr fossil fuel(Department of Climate Care, 2008)
Lehmann et al, 2008, Nature Geoscience 1, 832 - 835
Biochar Stability and Storage Time
About 1.5 to 2 orders of magnitude greater than uncharred biomass
Mean residence time in soil: ~1000 years (at 10°C)Baldock and Smernik, 2002, Organic Geochemistry 33, 1093-1109Bruun et al., 2008, Organic Geochemistry 39, 839-845Cheng et al., 2008, Journal of Geophysical Research, 113, G02027Lehmann et al, 2008, Nature Geoscience 1, 832 - 835 Liang et al, 2008, Geochimica et Cosmochimica Acta 72, 6096-6078Kuzyakov et al., 2009, Soil Biology and Biochemistry 41, 210-219 Major et al., 2009, Global Change Biology, doi: 10.1111/j.1365-2486.2009.02044.x
Biochar Stability - Measurements
Nguyen, Lehmann et al., 2008, Biogeochemistry 89: 295-308
(BC from forest clearing,false-time series on UltisolsWestern Kenya)
Large proportion of physical export likely
0 20 40 60 80 100
BC
con
tent
s (m
g C
g-1
soil)
0
2
4
6
8
10
12
14
16A
BC=3.51+9.16e-0.12years
R2=0.80, P=0.02
Age (years since BC deposition)
MRT of 8 years
(BC quantified by NMR and molecular mixing model)
Biochar Stability - Measurements
Hammes et al., 2008, Biogeosciences Discussions 5: 661-683
at 1900
Biochar-type carbon (probably low estimate)Russian Steppe Soil
at 1997
Biochar Fate in Soils
20-53% eroded!(Challenge for Carbon Trading)
Cumulative flux over 2 years Proportion of applied BC (%)
Respired as CO2 4.0
Leached as large particles POC (below 0.3m) 0.5Leached as small particles DOC (below 0.3m) 2.0
Major et al., 2009, Global Change Biology, doi: 10.1111/j.1365-2486.2009.02044.x
Colombian Llanos
Biochar Stability - Measurements
Surface oxidation?
Brodowski, 2005, PhD thesis
(pooled data from corn and rye BC (350°C), 20°C, at 70% water holding capacity, 3 replicates)
Measured using the BPCA biomarker method
Important Nuances? Quality of Biochar
Corn-BC Oak-BC0
5
10
15
20350°C600°Ca
bb b
(1 year, 30°C, in sand culture, N=8)
Car
bon
loss
rate
(% y
ear-1
)
Nguyen and Lehmann, 2009, Organic Geochemistry 40, 846-853
A (corn-350-BC) B (corn-600-BC)
5 nm 5 nm
Biochar Stability and StabilizationChemical stability + particulate nature + mineral?
(a) (b)
(c) (d)
Lehmann et al, 2008, Nature Geoscience 1, 238-242Lehmann et al, 2009, in: Earthscan Publ
10 μm
Total Carbon Black Carbon
Stabilization by Interactions with Minerals?
2 μm
aromatic carbon aliphatic carbon
carboxylic carbon phenolic carbon
total carbon nitrogen calcium
iron aluminum
Unpubl. data
Effects of Biochar on Total GHG
BiocharCO2 N2O, CH4
?
Effects of Biochar on Total GHG
Wardle et al., 2008, Science 320: 629
Disappearance(≠decomposition!)Lehmann and Sohi, 2008, Science 321, 1295
Effects of Biochar on Total GHG
Spokas et al., 2009, Chemosphere 77: 574-581
HapludollBiochar from fast pyrolysis
Biochar added to 5g soil (g)
Time (days)
0 100 200 300 400 500Cum
ulat
ive
C m
iner
aliz
atio
n [m
g C
O2-
C g
-1 so
il]
0
2
4
6
8
10
12
LSD0.05
A LSD0.05
+OM
-OM
Anthrosol HAT
Adjacent HAT
Anthrosol ACU
Adjacent ACU
Anthrosol DS
Adjacent DS
+AOM
–AOM
Effects of Biochar on Total GHG
Liang et al., 2009, Organic Geochemistry published online
Lower C mineralization in BC-rich Anthrosols
AOM=sugar cane(isotope tracing)Incubation at 30°CN=4
(Terra PretaCentral AmazonBiochar ages range from 800 to 7,000 years)
Effects of Biochar on Total GHG
Liang et al., 2009, Organic Geochemistry published online
NS
Mineralization of added OM
BC-rich soils
P contents
+43-125%P<0.05
Microbial Biomass
+173-3200% +19-340%
Added OMin fraction >1.8g/cm3
AOM=sugar cane(isotope tracing)Incubation at 30°CN=4
Effects of Biochar on N2O Emissions
Bhupanderpal-Singh et al., 2009, JEQ in press
VertisolAlfisol
poultry manure 400°C
poultry manure 550°C
wood 550°C
wood 400°C
control
Up to 73% reduction
Partly no reduction control
Life-Cycle Emission Reductions
Roberts et al., in revision
Energy Balance
6.99.1Corn stover (crop residue)
6.99.0Wheat straw
5.37.0Switchgrass
2.33.0Forage corn
Biochar to soil
Biochar to energy
Energy balance (MJ/MJ), Slow pyrolysis
Pyrolysis40-55%carbon
75-90%carbon
75% mass loss
50% carbon loss
BIOMASS BIOCHAR
Gaunt and Lehmann, 2008, Environmental Science and Technology 42: 4152-4158
Emission Balance
Gaunt and Lehmann, 2008, Environmental Science and Technology 42: 4152-4158
12,551-18,5954083-7710Bioenergy crops
9575-11,8332002-3736Crop residues
Biochar to soilBiochar to energy
Avoided Emissions (kg CO2/ha/yr), Slow pyrolysis
Fuel Efficiency – Cook StovesLower indoor pollution=lower respiratory
+ eye infectionsCase Study Kenya
Traditional Stove Improved Stove Biochar Stove
Mas
s (g
/kg
food
coo
ked)
-400
-200
0
200
400
600
800
1000
1200
1400
1600Wood Use Crop Residues Charcoal Residue Biochar
baa
Fuel Efficiency – Cook StovesCase Study Kenya
Torres, unpubl. data (n=20 for biochar stove (first generation, to be improved);average of one day cooking)
Reduction in wood use: 51% (±SE3.4; n=20)(Torres, unpubl. data)
Can the same amount of energy be generated with half of the carbon emitted?
Life-Cycle Assessment: Emission Reductions
Whitman et al., unpublished
Kenya-based scenario of cook stoves
Model Sensitivity 350% 75% 95% 100%Total CO2e in soil compared to baseline per T biomass
2
1.5
1
0.5
00 25 50 75 100
Time (year)
Tota
l soi
l C st
ocks
as c
ompa
red
to 3
-sto
ne
syst
em, p
er u
nit f
uel (
tCO
2e/t
dry
biom
ass)
Model Sensitivity 350% 75% 95% 100%Total CO2e in soil compared to baseline per T biomass
2
1.5
1
0.5
00 25 50 75 100
Time (year)
Tota
l soi
l C st
ocks
as c
ompa
red
to 3
-sto
ne
syst
em, p
er u
nit f
uel (
tCO
2e/t
dry
biom
ass)
Emissions from gasifier stove(MacCarty et al 2008)
MRT of BC 100-1000yrsFraction of passive BC: 0.6-0.9Fraction of crop residue used: 0-100%Fraction converted to BC: 0.25-0.5Systems dynamics modeling (Vensim)
Best preliminary estimate:Emission reduction: 8 t CO2e/yrRevenue ($5/t CO2e): $40/yr/household
Fuel Efficiency
Torres, unpubl data
Case Study Western Kenya (Kakamega)
Fuel reduction:• Fuel security• Lower fuel acquisition time• Lower pressure on natural resources
Distance per headload: 2.1 km (0.1-6.3)Wood saved: 4.9 t/household/year (0.9-19.2)Time saved: 6.2 hours/household/week (0.5-32)(30 households)
Time (years)
0 20 40 60 80 100
Annu
al C
rop
Yiel
ds (t
dry
gra
in/h
a) -
long
plu
s sh
ort r
ains
3
4
5
6
7
8
9
10
3-Stone Stove Pyrolysis Stove
Traditional Stove
Biochar Stove
Crop Yield
Life-Cycle Assessment: Soil and Crop
Whitman et al., unpublished
Systems dynamics modeling (Vensim)
Case Study Western Kenya (Kakamega)
Biochar Accounting FrameworkParaguay
• Relatively easy counting• Proof of source possible (MIR, TG-IMS)• Low risk of rapid evasion• Result of multiple emission reductions
Biochar Quantification in Soils
Hammes et al, 2007, Global Biogeochem Cycles
Biochar Quantification in Soils
Janik et al, 2007, AJSS
Mid-Infrared versus UV-NMR
Rapid methodInexpensiveLimited sample prep
Biochar Quantification in Soils
Unpubl. data (Lopez-Capel, Manning, Lehmann)
Wood biochar
δ13C -21‰
δ13C -24‰
Emissions Accounting
Biochar CO2 N2O, CH4
N2O, CH4N2O, CO2
Time since conversion (years)
0 20 40 60 80 100 120
Mai
ze g
rain
yie
ld (t
ha-1
)
2
4
6
8
10
12BiocharSawdust Manure Tithonia
LSD0.05
Growth Enhancement Dependent on Soil Properties
Kimetu et al., 2008, Ecosystems 11: 726-739
Biochar applied each seasonKenya (n=3)
The Way Forward
Platforms/Typology of biochar Systems:
- systems emission balance can be calculated- biochar quality can be controlled- soil effects can be estimated
WasteManagement
EnergyProduction
SoilImprovement
Mitigation ofClimate Change
Social, Financial Benefits
Biochar Benefits – Systems Dimension
WasteManagement
EnergyProduction
SoilImprovement
Mitigation ofClimate Change
Social, Financial Benefits
Biochar Benefits – Systems Dimension
WasteManagement
EnergyProduction
SoilImprovement
Mitigation ofClimate Change
Social, Financial Benefits
Biochar Benefits – Systems Dimension
WasteManagement
EnergyProduction
SoilImprovement
Mitigation ofClimate Change
Social, Financial Benefits
Biochar Benefits – Systems Dimension
Biochar – The Way Forward
Not “WHETHER”, but “WHERE”
Variation but also Uncertainties
Nitrogen balance
Biochar handling
Quantification of site-specific effects
Thanks
National Science Foundation – Ecosystem Sciences, Geobiology and Biocomplexity Programs, NSF-IGERT, USDA-NRI, USAID
Rothamsted Research, INPA and Cornell University for financial support.Sue Wirick, Chris Jacobsen, Mirna Lerotic (SUNY Stony Brook), Chithra
Karunakaran (CLS) for their help with sample analysis.Eduardo Neves, Fernando Costa (Universidade de Sao Paulo), James Petersen
(University of Vermont), Manuel Arroyo-Kalin (University of Birmingham) for the samples.
Lindsey Keller (Johnson Space Center), Jim Heyne for discussion about embedding.
Akio Enders (Cornell University) for sample preparation.Yuanming Zhang (Cornell University) for invaluable help with sectioning.Saran Sohi, Dawit Solomon, Biqing Liang, Julie Major, James Kinyangi, Chih-Hsin
Cheng, Janice Thies, Jan Skjemstad, Evelyn Krull, Kelly Hanley, Kelli Roberts, Thea Whitman, Dori Torres and many others