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Annual Meeting 2010
Istanbul, 21-22 April
Round Table
Can agricultural investment coexist with climate change policies?
Soil carbon sequestration
Martial Bernoux
April 22, 2010
Functionnal Ecology & Biogeochemistry of Soils & Agro-ecosystems
Background
Agriculture and Forestry are key sectors of Climate Change
presenting a dual aspect.
Responsible for ~ 1/3 of total direct GHG emissions
…But with an important mitigation potential
Mt CO2equivalent per year
About 89 per cent of this
potential can be achieved by
soil C sequestration through
cropland management, grazing
land management, restoration
of organic soils and degraded
lands, bioenergy and water
management*
Global mitigation potential by 2030
(from Smith et al., 2007)
* From UNFCCC Technical paper:
Challenges and opportunities for
mitigation in the agricultural sector,
2008
Background
Agriculture and Forestry are key sectors of Climate Change
concerns presenting a dual aspect.
Responsible for ~ 1/3 of total direct GHG emissions
…But with an important mitigation potential
Mt CO2equivalent per year
Global mitigation potential for each
region by 2030
(Extract from Smith et al., 2007)
EastAgri countries represent
mitigation potential of at least
~800 MtCO2-eq / year
(i.e. ~14% of global potential)
Global mitigation potential by 2030
(from Smith et al., 2007)
Background
Agriculture and Forestry are key sectors of Climate Change
concerns presenting a dual aspect.
…But with an important mitigation potential
Part of this potential is attainable at
“low” or even negative cost
Background
Agriculture and Forestry are key sectors of Climate Change
concerns presenting a dual aspect.
…But with an important mitigation potential
Currently this potential is mainly developed in the forestry
sector for several reasons but mainly:
- Easy and low cost to monitor
- Under the Kyoto Protocol: only afforestation/reforestation
projects are eligible under the Clean Development Mechanism
However, mitigation potential of agricultural soils is gaining acceptance and
projects are being developed worldwide
- Under voluntary markets such as the BioCarbon fund, the CCX…
- Canada, Portugal, Spain and Denmark already elected cropland
activities to officially account for soil C sequestration under the KP
- Discussions in the climate negotiations on REDD plus
- Development of tools for ex-ante appraisal of C-Balance (FAO, GEF…)
- Development of analytical solution for field C determination
How Soil Carbon sequestration Works
C inputs through
residues decomposition
C inputs
through
root
system
C stock is the result of
the balance of:
•Inputs
•Output (mineralization)
It is thus necessary to implement best management practices that
would increase the inputs or/and decrease the outputs in order to
promote soil C sequestration
Example of soil management practices which increase soil carbon
Suppression of the burning
(harvest residues…)
Improve soil fertility and
plant biomass production
Improve management:
Reduce/no tillage and/or
cover crop/mulch
Conservation Agriculture
Conservation agriculture definition (FAO):
1. Minimal Soil Disturbance: the disturbed area must be less than 15
cm wide or 25% of the cropped area (whichever is lower). No periodic
tillage that disturbs a greater area then the aforementioned limits.
2. Soil cover: Ground cover must be more than 30%
3. Crop rotation: Rotation should involve at least 3 different
crops. However, monocropping is not an exclusion factor
Soil carbon
mineralization
Decrease soil
carbon stock
Residues
Increase soil
carbon stock
Conservation agriculture and Soil C sequestration
Impact of adoption of conservation agriculture on soil carbon stocks
Soil C
accumulation
Soil Carbon
Conventional
Agriculture
Conservation
Agriculture
CA also promotes economy of fossil fuel consumption (permanent benefit)
Adoption of Conservation Agriculture
CA/No-tillage in the world in 2007/08 (million ha)
Total World: ~110 Million ha
Evolution of Global Area under Conservation Agriculture
(Million
Ha)
Russia
2.0 *
Canada
13.5
USA
26.6
Europe 1.1
120
100
Asia 2.5
80
60
40
20
Africa
0.4
-
Paraguay 2.4
Other South
America 2.0
Brazil
25.5
1983-1987
Argentina
19.7
Statistics from Derpsch and Friedrich, 2009
1988-1992
1993-1997
1998-2002
2003-2007
Australia
12.0
*Roberts and Johnston, 2009
Different
forms of “no-tillage”
Conservation
Agriculture:
a challenging definition
Statistics are dependent of definition used: example from France
CA official number for France: 150 000 ha (2003-2007) from FAO-CA site
France published in 2007 a review of “non-inversion tillage methods”
Those techniques were used on a third (4.6 Mha) of the total arable area in 2005
They are being implemented throughout France, regardless of crop and soil type
Common (bread) wheat
(Triticum aestivum)
% of plots with no-till
Durum wheat
(Triticum durum)
Carbon sequestration rates for Conservation Agriculture
Lal et al., 1995
- Semi-arid and subtropical:
- Temperate:
tCO2-eq ha-1 yr-1
0.15-0.7
0.35-1.8
Six et al., 2002
- Temperate and some Tropical (0-30 cm): 1.1 ± 0.4
Bernoux et al., 2006
- (Brazil) tropical and subtropical (0-40 cm): 1.4 to 6.2
Area of CA in Brazil is forecasted to reach 40 Mha in 2020, Cerri et al.(2010)
calculated that this will correspond to an additional mitigation of 140 Mt CO2-eq in
2010-2020, with 7 Mt CO2-eq corresponding to avoided emission from fossil fuel.
CA: Benefits and Adoption Obstacles
Benefits of conservation agriculture:
• Increased soil organic matter and fertility
• increased profitability by reducing costs for soil preparation
• possibility to have two crops in warmer climates
Obstacles to adoption:
•
•
•
•
•
Challenging technological changes
challenges to manage weeds
increased cost for herbicides (at least initially)
challenges to update farm machinery
difficulty to handle crop residues
These challenges make adoption easier in larger farms, and more
challenging (but not impossible or even less beneficial) in smaller
farms. That is why adoption takes time
How to promote agriculture investment in line with climate change policies
There is a lack of tools that would help project designers to integrate significant
climate response activities in agriculture development projects.
Investments in such activities would received due attention at project development
stage if justified by reasonable carbon ex-ante appraisals
FAO developped EX-ACT (Ex-Ante Carbon-balance tool) to help Assessing
potential mitigation benefits of agricultural investment projects
• Set of linked Microsoft
Excel sheets (19)
• Based on land use and
management practices
• Using IPCC default
values (Tier 1) and ad
hoc coefficients (Tier 2)
• Measures C-balance
with/without project
http://www.fao.org/tc/tcs/exact/events/en/
How to promote agriculture investment in line with climate change policies
Part of the solution is in our hands!
Science has brought evidences….
Consumers already ask for products with low GHG impact ….
Now…political decisions are also needed