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Emission of greenhouse gases (in agriculture) and climate change

Annette Freibauer

Johann Heinrich von Thünen-Institute Institute of Agricultural Climate Change

Braunschweig, Germany Reggio Emilia, 25 May 2010

Contents

• Agriculture as source of GHG emissions – System boundaries

– Main sources in Italy and Germany – Trends since 1990

• Agricultural solutions to climate change – Nitrogen efficiency

– Soil carbon – Bioenergy

– Food processing

Climate change

Source

Solution

„Victim“

Agriculture in climate change

System boundaries: „agriculture“

Energy in agriculture

CH₄, N₂O Animal husbandry

N₂O Fertilization

C stock change in

soil and biomass

Land use change Pre-chains

UNFCCC and Kyoto Protocol:

(Industry) Energy Agriculture Land use, Land use change National environmental accounting

Agriculture Widest definition of agricultural sector:

including import and embedded emissions in pre-chains

System boundaries: GHG emissions from German agriculture and land use

CO 2-equivalents (Gg a-1 )

0 30000 60000 90000 120000 150000

Enteric fermentation Manure management N₂O N in soils

C stock change Energy use

Fertilizer production Feed import

Main GHG sources in agriculture:

Italy

I

N2O All soils

Other

CH4 manure Dairy cattle

CH4 manure Swine CH4 manure Other

animals N2O manure All

animals

CH4 manure Other cattle

CH4 ent. ferm.

Other animals

CH4 ent. ferm.

Swine CH4 ent. ferm.

Other cattle CH4 ent. ferm.

Dairy cattle

I

CH4 ent. ferm. Dairy cattle CH4 ent. ferm. Other cattle CH4 ent. ferm. Swine

CH4 ent. ferm. Other animals CH4 manure Dairy cattle CH4 manure Other cattle CH4 manure Swine

CH4 manure Other animals N2O manure All animals N2O All soils

Other

Main GHG sources in agriculture:

Italy versus Germany

D

Italy

Germany

GHG sources in agriculture: Italy

• High importance of animal husbandry

1. Dairy cattle 2. Other cattle 3. Swine

4. Poultry 5. Sheep 6. Buffalo

• Other important sources

– N fertilization of soils – Rice paddies

Total GHG trends in Europe

Total GHG emissions

0 10 20 30 40 50 60 70 80 90 100 110 120

1990 1991

1992 1993

1994 1995

1996 1997

1998 1999

2000 2001

2002 2003

2004 2005

2006 2007

2008

% of 1990

EU-27 Germany Italy

Goal for 2020

Agricultural GHG trends in Europe

Agricultural GHG emissions

0 10 20 30 40 50 60 70 80 90 100 110

1990 1991

1992 1993

1994 1995

1996 1997

1998 1999

2000 2001

2002 2003

2004 2005

2006 2007

2008

% of 1990

EU-27 Germany Italy

Goal for 2020

GHG trends in agriculture:

CAP reform but no dedicated measures

• CH₄ reduction

– Efficiency increase in milk production: less dairy cattle for same amount of milk per year

– Market effect: reduction in non-dairy cattle – But: increase in swine and poultry

– Small (non-quantifiable) effect: biogas from slurry

• N₂O reduction

– Shift from mineral to organic fertilizer – Lower N surplus

• CO : unclear

Climate change

Source

Solution

„Victim“

Agriculture in climate change

Options for climate change mitigation Options for climate change mitigation

Land use

 Afforestation

 Restoration of wetlands

 No conversion of grass to crop

Agricultural production

 Improve N efficiency

 Slurry storage / Biogas

 Reduced animal production

 Improved animal performance

 Change in cattle herd structure

 Adapted diet (CH₄ , N)

 Pasture instead of housing?

 C sequestration in cropland?

 Organic farming?

Land use

 Nice, if renewable biomass!

 -20 bis -40 t CO₂/ha/a

 Reference?

Potential per hectare

 -40 kg N-surplus: 0.2 t CO₂/ha/a

 Cover of slurry store; NH₃, N₂O?

 Ca. -20% since 1990 in Germany

 Ca. -10% since 1990 in Italy

 ? Max. -10% (farm structure!)?

 ? Long-term? Where best?

 ? -10 bis -20% GHGs / Product

}

N fertilization and

N

O emissions from soil

• Calculation in national inventory according to IPCC Guidelines 2006, 1996

Linear increase of N₂O-Emissionen with N input 1,25% (0,25 – 2,5%) of N input converts to N₂O N input =

• Mineral and organic fertilizers

• Crop residues

• Peat oxidation in drained peatland

• N deposition as NH₃ und NO_x

• N from leached nitrate

 Mitigation = less N input and loss (fertilizer, NH₃, nitrate)

Regional N

O emission factors:

Effect of N surplus

N use efficiency (%) N 2O-N (kg ha-1 )

0 20 40 60 80 100

0 2 4 6 8

van Groenigen, 2004 Sand

Clay Outlier

Carbon sequestration in agricultural soils

• Change in crop rotation and rooting depth?

• Increased yield? (only when increased root mass)

• Low-till or no-till?

• Solid organic fertilizers from biogas digestate on carbon poor crop soils: interesting option! Effect known for solid manure.

• New substrates (biochar)???

 Synergy with adaptation to climate change (resilience of soil)

 C sequestration effect currently not quantifiable at large scale

Quality of organic amendments

0 0.2 0.4 0.6 0.8 1

farm yard manure beet leave

straw

green manure liquid manure, cattle

liquid manure, pig bio waste com

post

green waste com post

sewage sludge (SS) SS com

post

waste-SS com post

waste com post

waste com post Fraction of carbon in fertilizer Easily degradable plant carbon Recalcitrant plant carbon Humified carbon

 Composting or digestion increases stable C fraction

 Large variability within the same type of substrate

0 4 8 12 16 20

Produktion von Bioenergieträgern

CO 2-equivalents (t ha-1 )

CO₂

Substitu- tion

potential

HeatHeat Electricity and CHPElectricity and CHP FuelsFuels

Hack- schnitzel Getreide Gülle/Strom + Wärme Mais/Strom Mais/ Einspeisung

Mais/Strom + Wärme Hackschnit. HKW Stroh Co- Verbrennung Hackschnitt. Co-Verbr. Biodiesel Ethanol (Weizen) Biogas (Kraftstoff)

--- Biogas ---

Wiss. Beirat Agrarpolitik, 2008

--- Biogas ---

CO₂

Substitution cost

-100 0 100 200 300 400 500

CO 2-cost (EUR t CO 2-eq.) ood chips Cereals Slurry / CHP ize / elec. Maize / Elec. grid

Maize / CHP ood chip / CHP Straw / co- ombustion ood chips Co-combu. Biodiesel Ethanol (Wheat) Biogas (Fuel)

Global CO

abatement costs

McKinsey 2008

Tillage & residues

Organic soil restoration N management

Rice management

2^nd generation biofuels

Biomass cofiring

Management Bioenergy Land use, Land use change

„Carbon footprint“ of food products

0 3000 6000 9000 12000 15000 18000

fresh frozen

CO 2-equiv. / kg raw product

Beef Pork Chicken

Min/Max

Flachowski & Lebzien, 2009 Fritsche & Eberle 2007;

CO 2-equiv. / kg product

fresh

dried

Pommes Kartoffeln

0 2000 4000 6000

Potatoes

Conclusions

• Animal husbandry and N fertilization contribute ~6% to national GHG emissions

• So far no direct incentives for GHG-efficient production

• Agriculture must adapt to climate change by soil and water management: risk control and resilience!

• Agriculture can reduce GHG emissions by enhanced nutrient and energy efficiency

• Agriculture can produce renewable material and energy

• Biogas from animal manure and organic waste with solid digestate for C-depleted soils offers synergy for all three.