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Presentation made by Andy Jarvis in Bellagio, Italy at the Second Strategic Meeting of the Global Cassava Partnership for the 21st Century on the 2nd November, 2010.
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Climate change and the outlook for Cassava
Andy Jarvis and Julian Ramirez
Climate change is not new…but is accelerating
Global Climate Models (GCMs)
• 21 global climate models in the world, based on atmospheric sciences, chemistry, biology, and a touch of astrology
• Run from the past to present to calibrate, then into the future
• Run using different emissions scenarios
So, what do they say?
Temperatures rise….
Changes in rainfall…
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
-100 0 100 200 300 400 500 600 700
Cumulated precipitation anomaly (mm) A1b
Cu
mu
late
d t
emp
erat
ure
an
om
aly
(ºC
) A
1b
Angola Ghana India Malawi Mozambique
Uganda Tanzania Nigeria Congo
1870 Baseline
2020 modelingtime-limit
2050 modelingtime-limit
2099 modelingtime-limit
TRENDS IN CLIMATE FOR CASSAVA GROWING ENVIRONMENTS
Climate changes in cassava growing environments
0.6
0.7
0.8
0.9
1.0
1.1
1.2
1.3
1.4
-250 -150 -50 50 150 250
Change in precipitation (mm)
Ch
an
ge
in t
em
pe
ratu
re (
°C)
AustralasiaCaribbeanCentral AfricaCentral AmericaEastern AfricaSouth AmericaSouthern AfricaWestern Africa
NGATHA
IDN
BRA
LBRCRI COL
MWI
•Crops develop more quickly in higher temperatures
Pritchard and Amthor 2005
Cassava – an exception to the rule?
•In many cases, roughly 6-10% yield loss per degree
•For example, US maize, soy, cotton yields fall rapidly when exposed to temperatures >30˚C
Schlenker and Roberts 2009 PNAS
Impacts of climate change to food security
• Lobell et al. looked at impacts of climate change on food security
• Cassava clearly highlighted as suffering least among many staples
• Particular opportunities as an alternative crop for southern Africa
Nothing new!
The Model: EcoCrop
It evaluates on monthly basis if there are adequate climatic conditions within a growing season for temperature and precipitation… …and calculates the climatic suitability of the
resulting interaction between rainfall and temperature…
• So, how does it work?
Current suitability
Growing season (days) 240 Killing temperature (°C) 0
Minimum absolute temperature (°C)
15.0
Minimum optimum temperature (°C)
22.0
Maximum optimum temperature (°C)
32.0
Maximum absolute temperature (°C)
45.0
Minimum absolute rainfall (mm)
300
Minimum optimum rainfall (mm)
800
Maximum optimum rainfall (mm)
2200
Maximum absolute rainfall (mm)
2800
Current climatic constraint
Future suitability and change (2020s)
0
1
2
3
4
5
6
7
8
9
10
-2.5ºC -2ºC -1.5ºC -1ºC -0.5ºC None +0.5ºC +1ºC +1.5ºC +2ºC +2.5ºC
Crop resilience improvement
Ch
ang
e in
su
itab
le a
reas
[>
80%
] (%
)
Cropped landsNon-cropped landsGlobal suitable areas
Heattolerance
Coldtolerance
Breeding priorities
0
1
2
3
4
5
6
7
8
9
10
-25% -20% -15% -10% -5% None +5% +10% +15% +20% +25%
Crop resilience improvement
Ch
ang
e in
su
itab
le a
reas
[>
80%
] (%
)
Cropped landsNon-cropped landsGlobal suitable areas
Waterloggingtolerance
Droughttolerance
…….and for Latin America?Drought or flooding tolerance
30% of current cassava fields would benefit from enhanced drought or flooding tolerance
1.6m Ha still suffering climatic constraint
2.23m Ha of current production
2.1m Ha of new land would become suitable for cassava
0
5
10
15
20
25
30
35
-2.5% -2% -1.5% -1% -0.5% None +0.5% +1% +1.5% +2% +2.5%
Mejora en la resiliencia de los cultivos
Cam
bio
en
áre
as a
dap
tab
les
[>80
%]
(%)
Áreas cultivadas
Áreas no-cultivadas
Total áreasadaptables
Toleracia a sequias
Toleracia a inundación
0
5
10
15
20
25
30
35
-2.5% -2% -1.5% -1% -0.5% None +0.5% +1% +1.5% +2% +2.5%
Mejora en la resiliencia de los cultivos
Cam
bio
en
áre
as a
dap
tab
les
[>80
%]
(%)
Áreas cultivadas
Áreas no-cultivadas
Total áreasadaptables
Toleracia a sequias
Toleracia a inundación
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
Ropmin Ropmax Not benefited
Áre
as b
enef
icia
das
(m
illi
ón
de
hec
táre
as)
Áreas cultivadas actualmente
Áreas no-cultivadasactualmente
…….and for Latin America?Heat or cold tolerance
27% of current cassava fields would benefit from enhanced cold or heat tolerance
2.23m Ha of current production
2.2m Ha of new land would become suitable for cassava
0
2
4
6
8
10
12
-2.5ºC -2ºC -1.5ºC -1ºC -0.5ºC None +0.5ºC +1ºC +1.5ºC +2ºC +2.5ºC
Mejoramiento en la resiliencia del cultivo
Cam
bio
en
áre
as a
dap
tab
les
[>80
%]
(%)
Áreas cultivadas
Áreas no-cultivadas
Total áreas adaptables
Toleracia al calor
Toleracia al frío
0
2
4
6
8
10
12
-2.5ºC -2ºC -1.5ºC -1ºC -0.5ºC None +0.5ºC +1ºC +1.5ºC +2ºC +2.5ºC
Mejoramiento en la resiliencia del cultivo
Cam
bio
en
áre
as a
dap
tab
les
[>80
%]
(%)
Áreas cultivadas
Áreas no-cultivadas
Total áreas adaptables
Toleracia al calor
Toleracia al frío
0
1
1
2
2
3
Topmin Topmax Not benefited
Áre
as b
enef
icia
das
(m
illó
n d
e h
ectá
reas
) Áreas cultivadas actualmente
Áreas no-cultivadasactualmente
A bright future for cassava?
CHANGE IN SUITABILITY FOR CASSAVA - 2050
Negative
Positive
CHANGE IN SUITABILITY FOR
MAIZE - 2050
Negative
PositiveContrasting responses between maize and cassava: 2-3oC temp rises, changes in prec
A big unknown….
Change in Green Mite pressure to 2020
Changes in Whitefly prevalence to 2020
Areas for research
• CO2 impacts on cassava• Climate change impacts on quality…and toxicity
Pests and disease response
• Sound experimental multi-environment trials• Coupled with modelling• Allowing us to understand thresholds
•Direct damage to reproductive cells (e.g. rice spikelet sterility)