Effects of climate change on global wheat production and ... · Climate change & green house effect...
Transcript of Effects of climate change on global wheat production and ... · Climate change & green house effect...
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
Senthold Asseng, Effects of climate change on global wheat production and food security, Goettingen, Germany, 14 June, 2017
Outline
1. The agricultural challenge
2. Simulation models – AgMIP – multi-model approach
3. Temperature & CO2 impact
4. Summary
Senthold Asseng, Effects of climate change on global wheat production and food security, Goettingen, Germany, 14 June, 2017
The Agricultural Challenge
Increasing Food Demand
Population increase
Senthold Asseng, Effects of climate change on global wheat production and food security, Goettingen, Germany, 14 June, 2017
The Agricultural Challenge
Increasing Food Demand
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
Senthold Asseng, Effects of climate change on global wheat production and food security, Goettingen, Germany, 14 June, 2017
The Agricultural Challenge
Increasing Food Demand
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
Senthold Asseng, Effects of climate change on global wheat production and food security, Goettingen, Germany, 14 June, 2017
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
Senthold Asseng, Effects of climate change on global wheat production and food security, Goettingen, Germany, 14 June, 2017
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
Senthold Asseng, Effects of climate change on global wheat production and food security, Goettingen, Germany, 14 June, 2017
NASA
Past temperature trend
Senthold Asseng, Effects of climate change on global wheat production and food security, Goettingen, Germany, 14 June, 2017
Knutti and Sedlacek 2013 Nature CC
Future temperature trend
Senthold Asseng, Effects of climate change on global wheat production and food security, Goettingen, Germany, 14 June, 2017
The Agricultural Challenge
Increasing Food Demand
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)
Senthold Asseng, Effects of climate change on global wheat production and food security, Goettingen, Germany, 14 June, 2017
Complexity
Increasing Food
Demand
Nutritional value
Environmental impact & sustainability
Food production
system
Climate Change
Senthold Asseng, Effects of climate change on global wheat production and food security, Goettingen, Germany, 14 June, 2017
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
Senthold Asseng, Effects of climate change on global wheat production and food security, Goettingen, Germany, 14 June, 2017
Modeling (Wheat) Cropping Systems
CO2 Light
Temperature Rainfall/Irrigation
Crop Management
Carter 2013
Soil
Time
Ozone
Cultivar Agronomy
Breeding
Senthold Asseng, Effects of climate change on global wheat production and food security, Goettingen, Germany, 14 June, 2017
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)
Senthold Asseng, Effects of climate change on global wheat production and food security, Goettingen, Germany, 14 June, 2017
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Median
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Location
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Model ranking (to observation) 6-CIMMYT hot locations (2 cultivars) 4-pilot locations – contrasting conditions
Senthold Asseng, Effects of climate change on global wheat production and food security, Goettingen, Germany, 14 June, 2017
Multi-model ensembles
Season mean temperature (°C)
15 20 25 30 35
Gra
in y
ield
(t/
ha)
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Season mean temperature (°C)
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Bruce Kimball
Asseng et al. 2015 Nature CC
Senthold Asseng, Effects of climate change on global wheat production and food security, Goettingen, Germany, 14 June, 2017
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
Senthold Asseng, Effects of climate change on global wheat production and food security, Goettingen, Germany, 14 June, 2017
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 (-)
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9
12
15Colors represent
different CO2 levels
(13.5% = Mean exp CV% (Taylor et al. 1999))
Mean (+/- STD) of all locations
Asseng et al. 2013 Nature CC
Senthold Asseng, Effects of climate change on global wheat production and food security, Goettingen, Germany, 14 June, 2017
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
Senthold Asseng, Effects of climate change on global wheat production and food security, Goettingen, Germany, 14 June, 2017
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:
Senthold Asseng, Effects of climate change on global wheat production and food security, Goettingen, Germany, 14 June, 2017
Multi-model ensembles to reduce uncertainty
Model improvements reduce required number of models in multi-model ensembles
Maiorano et al. 2016 FCR
Senthold Asseng, Effects of climate change on global wheat production and food security, Goettingen, Germany, 14 June, 2017
Wheat Yield decline with increasing temperature
Asseng et al. 2015 Nature CC
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
Senthold Asseng, Effects of climate change on global wheat production and food security, Goettingen, Germany, 14 June, 2017
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
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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
Senthold Asseng, Effects of climate change on global wheat production and food security, Goettingen, Germany, 14 June, 2017
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 (%)
Senthold Asseng, Effects of climate change on global wheat production and food security, Goettingen, Germany, 14 June, 2017
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]