Effects of climate change on global wheat production and ... · Climate change & green house effect ... Temperature Rainfall/Irrigation Crop Management ... Effects of climate change

Senthold Asseng, Effects of climate change on global wheat production and food security, Goettingen, Germany, 14 June, 2017

Effects of climate change on global wheat production and food security

Senthold Asseng

P. Martre, A. Maiorano, R.P. Rötter, G. O’Leary, G. Fitzgerald, C. Girousse, M.A. Baber, M.P. Reynolds, F. Giunta, R. Motzo, A.M.S. Kheir, P.J. Thorburn, K. Waha, A.C. Ruane, P.K. Aggarwal, M. Ahmed,

J. Balkovic, B. Basso, C. Biernath, M. Bindi, D. Cammarano, A.J. Challinor, G. De Sanctis, B. Dumont, E. Eyshi Rezaei, E. Fereres, R. Ferrise, M. Garcia-Vila, Y. Gao, S. Gayler, G. Hoogenboom,

R.C. Izaurralde, M. Jabloun, C.D. Jones, B.T. Kassie, K.C. Kersebaum, C. Klein, A.K. Koehler, B. Liu, S. Minoli, M. Montesino San Martin, C. Müller, S. Naresh Kumar, C. Nendel, J.E. Olesen, T. Palosuo,

J.R. Porter, E. Priesack, D. Ripoche, M.A. Semenov, C. Stöckle, P. Stratonovitch, T. Streck, I. Supit, F. Tao, M. Van der Velde, D. Wallach, E. Wang, H. Webber, J. Wolf, P. Woli, Z. Zhang, and Y. Zhu,

F. Ewert


Outline

1. The agricultural challenge

2. Simulation models – AgMIP – multi-model approach

3. Temperature & CO2 impact

4. Summary


The Agricultural Challenge

Increasing Food Demand

Population increase




Population increase

People:

• 3 B in 1960

• 7.3 B now

• >9 B in 2050

800 M undernourished

(declined by 100 M in last 14 year)

BUT (West et al. 2014 Science)…

Undernourished population

Source: United Nations Statistics 2012

Food Waste

http://lifereallymatters.com

Overweight

Calories (T kg)

Food

Feed

Other

Global calorie production

West et al. 2014 Science

1961 1980 2000 2009 Year




Population increase

Need 60% more food in 2050 (Alexandratos & Bruinsma 2012 FAO Report)

Increase nutritional value

Reduce environmental impact (Irrigation in agriculture = 70% of global water withdrawals with India, Pakistan, China, USA =

72% of all irrigation) (West et al. 2014 Science)

High risk of surface water pollution across the world

Ippolito et al. 2015 Environmental Pollution

Climate Change


Climate change & green house effect

Carbon dioxide acts like a blanket, absorbing IR radiation & preventing it from escaping into outer space. - net effect heating of Earth


Since when do we know about climate change?

Arrhenius 1896 Philosophical Magazine and

Journal of Science

- doubling of atmospheric CO2 could cause

an increase in Earth’s surface temperature

of 11°F to 14.5°F

(5.5°F to 9°F suggest by GCMs) Swedish chemist

Svante Arrhenius


NASA

Past temperature trend


Knutti and Sedlacek 2013 Nature CC

Future temperature trend




Population increase

Need 60% more food in 2050

Increase nutritional value

Reduce environmental impact

Climate Change

Temperature increased by 1.0 oC

By 2050: Atmospheric CO2 >500ppm

By 2100:

Temperature +2 to 4 oC

More extremes (heat, droughts,

rainfall).

(IPCC 2015)


Complexity

Increasing Food

Demand

Nutritional value

Environmental impact & sustainability

Food production

system

Climate Change


1. Temperature increase

2. Increased CO2

3. More intense rainfall (Florida)

Potential climate change impacts

Positive Impact Negative Impact Change

• Less frost damage • Improved winter growth • Earlier planting

• Growth stimulus (if nutrients not limiting)

• Increased water use efficiency

• Reduced diseases? (longer dry periods)

• Faster phenology • Reduced chill hours • Increased heat stress • Increased water use • Increased pest/disease

• Reduced nutrition • Warmer canopies

(increased heat stress) • Increased weeds

• More runoff • More chemical leaching • More irrigation


Modeling (Wheat) Cropping Systems

CO2 Light

Temperature Rainfall/Irrigation

Crop Management

Carter 2013

Soil

Time

Ozone

Cultivar Agronomy

Breeding


x

x

x

x

AgMIP-Wheat

25 models consistent across 2 data sets: a) 4 pilot locations – contrasting conditions b) 6 CIMMYT hot locations (2 cultivars)


1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

Median

1 2 3 4 5 6 1 2 3 4 5 6

Location

Mo

del

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Rank value

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

Median

1 2 3 4

Location

Mo

de

l

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Rank value

Model ranking (to observation) 6-CIMMYT hot locations (2 cultivars) 4-pilot locations – contrasting conditions


Multi-model ensembles

Season mean temperature (°C)

15 20 25 30 35

Gra

in y

ield

(t/

ha)

0

2

4

6

8

10

12

Season mean temperature (°C)

15 20 25 30 35

Gra

in y

ield

(t/

ha)

0

2

4

6

8

10

12

Bruce Kimball

Asseng et al. 2015 Nature CC


Multi-model ensembles

Multi-model ensemble median is a better predictor than any single model !

• Wheat yields --- Asseng et al. 2013 Nature CC

• Wheat yields (heat stress) --- Asseng et al. 2015 Nature CC

• Wheat variables --- Martre et al. 2014 GCB

• Maize yields --- Bassu et al. 2014 GCB

• Rice yields --- Li et al. 2014 GCB

• Potato yields --- Fleisher et al. 2016 GCB


Multi-model ensembles to reduce uncertainty

Changes in temperature (oC)

-6 -3 0 3 6 9 12

Required number of crop models to achieve

<13.5% simulated impact variability (-)

0

3

6

9

12

15Colors represent

different CO2 levels

(13.5% = Mean exp CV% (Taylor et al. 1999))

Mean (+/- STD) of all locations



Simulating heat stress

Observed = symbols Simulation = lines

17/27℃

33/43℃

Model A Model B Model C Model D

Heat = 9 days around anthesis

Senescence acceleration routine with heat

Liu et al. 2016 GCB

LAI (-)

Day of year


Improved simulation of heat stress

Observed = symbols Multi-model simulation = shades (red shade = improved models)

Multi-model simulation medians = lines

Maiorano et al. 2016 FCR

Total biomass

(t/ha)

Growing season mean T:


Multi-model ensembles to reduce uncertainty

Model improvements reduce required number of models in multi-model ensembles

Maiorano et al. 2016 FCR


Wheat Yield decline with increasing temperature


6% decline in global wheat production for each degree in global warming

Wheat producing area

30 model ensemble median (& mean of 30 years)

+2 oC


Experiments

Assimilation

Root

Shoot + Leaf Grain

Residues(surface)

Residues(roots)

BIOMC:N

HUMC:N

FOM

carbohydartes

lignin

cellulose

Mineral-NNH

4 NO

3

urea NH4

Mineralisation

Immobilisation

Harvest

Leaching

C

N

C

N

N

C,N

C,N

CO2

TUE

Es

Ep

Denitrification

FertiliserCO2

CO2

CO2

CO2

LL SATDUL

runoff

Drainage

1

2

3

n

rainfallmax & min

temperature

solar

radiation

C

Water Soil

Crop

Phenology

Crop models

Impact

Multi-model points

US wheat yields

Statistical models

Global-gridded


Liu et al. 2016 Nature CC

Impacts of global temperature increase on global wheat yield estimated by different assessment methods

Impacts of 1oC

Consistent with observations (Fischer, Beyerlee and Edmeades 2015 Book: Crop Yields and Global Food Security)

Yield impact with 1oC

increase in global

temperature (%)

http://erae.oxfordjournals.org/content/early/2015/11/17/erae.jbv034.extract


Summary

1. Agricultural challenge is huge and complex; increasing yields is part of it,

2. Multi-model ensemble = best predictor across environments,

3. Ensemble of 2-5 models sufficient to reduce uncertainty to experimental

error; model improvements ---> less models required,

4. 6% decline in global wheat for each degree in global warming, - similar across methods, 5. Loss of CO2 growth stimulus with increasing temperature.

Contact: Senthold Asseng, [email protected]

Documents

Effects of climate change on global wheat production and ... · Climate change & green house effect ... Temperature Rainfall/Irrigation Crop Management ... Effects of climate change