Relieving agricultural GHG stress: thetransition of staple food strategy in China
Beibei Liu, Ph.D.
Associate Professor
School of Environment, Nanjing UniversityAugust, 2017

Outline

1Introduction

2Methodology

3Results and discussion

4Conclusion

Challenges of GHGs emission of Agriculture andWaste
Crop and livestock produc2on is responsible for up to1/3 total anthropogenic GHG emissions. (VermeulenS. J., et al, 2013)

China accounts for 17% of global agricultural emissions.
(Kimberly M. C., et al, 2017)
Currently agriculture GHGs are not well studied onregional and national level.
ü Difference on energy and material input
ü Geographical differenceü Crop management
ü Crop structureTransition of Staple Food strategy in China
Potato staple food strategy in China

Structure of staple food in China(2006-2015)
60000
40000

Potato staple food development strategy seminar2015.0120000
02006 2007 2008 2009 2010 2011 2012 2013 2014 2015
RiceWheat

Maize

Potato industry development instructions
2016.04

Fig1. Yields (10 thousand tons yr-1) for 3 staple crops
60000
40000

Beneﬁt of potato staple food

20000
02006 2007 2008 2009 2010 2011 2012 2013 2014 2015
RiceWheat

MaizePotatoFig2. Yields (10 thousand tons yr-1) for 4 staple crops

Ra2o of potato : 12.7%(2006)→14.5%(2015)
Potato yield Increases: 47.1%(2006-2015)•••

more food for the popula1on
more healthy for consumers
more income for farmers

Agriculture faces great challenges toensure food security by increasing yields
while reducing environmental costs.

Research Question

Ø Will the transition of staple food strategy in China contributeto GHG reductions? What about in global level?

ü Difference on energy and material input
ü Yield differenceü Crop management
ü Crop structureü GHG leakage

Outline

1

Introduction

2

Methodology

3

Results and discussion

4

Conclusion

GHGs emission of planting systems
Life Cycle Analysis
Uncertainty (McKone T. E., et al, 2011)
System boundary (Suh, S., et al, 2004; Suh, S., et al, 2005)
Emission factors (Chen H., et al, 2013; Hu N., et al, 2016; Xu S.P., et al, 2007)
Crop management prac2ces (Tilman D., et al, 2006; Chen X., et al, 2014)
Main Data source
CropsRegion

Data

RiceWheat
Maize
Potato31 provinces(mostly incity level) inChinamainland

Area harvested
Produc2onSources
China Rural Sta2s2cal Yearbook

Input of fer2lizer Compila2on of the Na2onal
and plas2c ﬁlm Agricultural Costs and Returns

GHGs emission of planting systems
Life Cycle Analysis
System boundary & emission components
1. CH4 emission during crop plan2ng

Production and transportation

2. N2O emission during fer2lizer

Fertilizers,
pesticidesDiesel,
electricity

applica2on3. GHG emissions during the produc2on

Crops planting

and transporta2on of agricultural

Ploughing

inputsSowingUncertainty iden2ﬁca2on

Fertilization/weeding• CH4 and N2O emission factor• Crop management prac2ces

HarvestFunc2on unit
• Produc2on intensity (Mg CO2e M kcal-1)

Crops

GHG emissions(CH4, N2O)

Fig1. System boundary

GHGemissions

Transition of staple food structure
Uncertainty

Uncertainty

Structure in 2020
before potato staple
food strategy

Unit yieldof prediction

Demand yieldsof prediction

Gap between crops is
replaced by potato
production

Production areas of planning

Yields of planning

Yields of planning

Rice

Rice

Rice

Wheat

Wheat

Maize

Maize

Wheat
Maize
PotatoFig2. Potato staple food strategy developmentStructure in 2020 acer
potato staple foodstrategy

GHG leakage due to staple food strategy
Causes of GHG leakage

Transition ofstaple foodstructure

Loyalty to riceof Chinese

Decline ofnative riceproduction

High intensityof export
countries

Increase of riceimport

GHG leakage

Main Data source
Crops

RegionData

Sources

Rice import rate China customs informa2on website
Rice

8 majorimportcountries

Area harvested
Produc2on

FAOSTAT

Appliedfer2liza2on rate

IFAOutline

1Introduction

2Methodology

3

Results and discussion

4Conclusion

Emissions status quo in 20153%
27%22%
48%

0.24
0.77
0.28
0.49
Fig3. Staple food greenhouse gas emissions and intensi2es of each crops in China

Methane:72% of rice emission;
34% of all crops.

High intensity of rice:
High Methane emissions
due to ﬂoodingHigh intensity of maize:High Nitrous Oxide and input
emissions from fer2liza2on rate

• Total staple food GHG emissions in China:
546.90 ± 32.69 Tg CO2e yr-1 (4.4 ± 0.2% of anthropogenic emissions)• Produc2on intensity of staple food in China:0.45 ± 0.13 Mg CO2e M kcal-1

Emissions status quo in 2015

Fig4. Staple food greenhouse gas emissions and intensi2es of each crops in China of each regions

Highest produc2on intensity:• South China(rice planta2on)• Northwest, Northeast, andNorth China(high fer2liza2on applied rate)

Fig5. Distribu2on of produc2on intensity (g CO2-eq kcal-1) from staple foods in 2015

Emissions status quo in 2015
RiceWheat

Maize

PotatoFig6. Distribu2on of produc2on intensity (g CO2-eq kcal-1) from each staple foods in 2015

Transition of staple food structure
700594.27 ±32.69

569.21±68.91
25.06 Tg CO2e yr-1
4.21±2.11%

600
500

Table1. Uncertainty sources of scenario 1400

Uncertainty
iden2ﬁed

ranges300

Potato yields

±10%

200

Unit yields

±10%

100

CH4 emission
factor of rice

Regionspeciﬁc

CH4 emission
factor ofothers

Crops speciﬁc

N2O emission
factorCrops speciﬁc0
BeforeRice

WheatAcer
Maize

PotatoFig7. GHG emissions (Tg CO2-eq yr-1) in 2020 for before and acertransi2on of staple food structure from 4 crops

Transition of staple food structureWith crop management

222 million tons
= 14.8% of reduc2on goal of China

ISSM: higher yield with beler nitrogen use eﬃciency
0.6

20.33±0.18%

53.49±0.13%

0.51±0.06

China’s Na*onal Plan on
Climate Change (2014-2020)

700

600
0.48±0.02

0.4

0.41±0.05

39.17±0.01%

500

400
0.28±0.02300
0.22±0.01

0.2
0.17±0.01

200

1000

Rice

Wheat
Without

Maize

WithFig8. GHG emission intensity (g CO2-eq kcal-1) for with or not crop
management for 3 crops

0BeforeRice

Without
Wheat

Maize

WithPotato

Fig9. GHG emissions (Tg CO2-eq yr-1) of each scenario from 4 crops in 2020

Transition of staple food structure
Double intensity of China
China(2015)
China
Japan
Russian Federa2on
Laos
MyanmarCambodia
PakistanThailand
Vietnam
0.00

0.20

0.40
CH₄0.60
N₂O

0.80

1.00

Input

Fig10. GHG emissions intensity (g CO2-eq kcal-1) of rice for import countries• GHG leakage:
30.10 - 42.12 Tg CO2e yr-1 (exceed emissions reduc2ons in na2ve China)

1.20

Outline

1

Introduction

2Methodology

3Results and discussion

4Conclusion

Conclusion
1. In 2015, total staple food GHG emissions in China was546.90±32.69 Tg CO2e yr-1; production intensity of staple
food in China was 0.45±0.13 Mg CO2e M kcal-1.
2. After transition of staple food structure, native GHG
emissions of staple food in 2020 might reduce 25.06 Tg
CO2e yr-1 (4.21±2.11%); further reduction (33.3-40.4%) could
be achieved with crop management improvement.
3. GHG leakage due to potato staple food strategy could
achieve 30.10-42.12 Tg CO2e yr-1, which may exceed
emissions reductions in native China.

Thank you!
Thank You!
Lbeibei@nju.edu.cn