Climate change and the outlook for cassava bellagio nov 2010

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)