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.

1. Climate change and the outlook for Cassava
Andy Jarvis and Julian Ramirez

2. Climate change is not new…but is
accelerating

3. 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

5. So, what do they say?

6. Temperatures rise….

7. Changes in rainfall…

8. -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
Cumulatedtemperatureanomaly(ºC)A1b
Angola Ghana India Malawi Mozambique
Uganda Tanzania Nigeria Congo
1870
Baseline
2020 modeling
time-limit
2050 modeling
time-limit
2099 modeling
time-limit

9. TRENDS IN CLIMATE FOR CASSAVA GROWING
ENVIRONMENTS

10. 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)
Changeintemperature(°C)
Australasia
Caribbean
Central Africa
Central America
Eastern Africa
South America
Southern Africa
Western Africa
NGA
THA
IDN
BRA
LBR
CRI COL
MWI

11. •Crops develop more quickly in higher temperatures
Pritchard and Amthor 2005

12. 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

13. 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

14. Nothing new!

15. 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?

16. 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

17. Current climatic constraint

18. Future suitability and change (2020s)

19. 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
Changeinsuitableareas[>80%](%)
Cropped lands
Non-cropped lands
Global suitable areas
Heat
tolerance
Cold
tolerance
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
Changeinsuitableareas[>80%](%)
Cropped lands
Non-cropped lands
Global suitable areas
Waterlogging
tolerance
Drought
tolerance

20. …….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
Cambioenáreasadaptables
[>80%](%)
Áreas cultivadas
Áreas no-cultivadas
Total áreas
adaptables
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
Cambioenáreasadaptables
[>80%](%)
Áreas cultivadas
Áreas no-cultivadas
Total áreas
adaptables
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
Áreasbeneficiadas(milliónde
hectáreas)
Áreas cultivadas actualmente
Áreas no-cultivadas
actualmente

21. …….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
Cambioenáreasadaptables
[>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
Cambioenáreasadaptables
[>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
Áreasbeneficiadas(millóndehectáreas)
Áreas cultivadas actualmente
Áreas no-cultivadas
actualmente

22. A bright future for cassava?

23. CHANGE IN
SUITABILITY FOR
CASSAVA - 2050
Negative
Positive

24. CHANGE IN
SUITABILITY FOR
MAIZE - 2050
Negative
Positive
Contrasting responses between maize and cassava:
2-3oC temp rises, changes in prec

25. A big unknown….

28. Change in Green Mite
pressure to 2020

29. Changes in Whitefly
prevalence to 2020

30. Areas for research
• CO2 impacts on cassava
• Climate change impacts on quality…and toxicity

31. 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)