Julian Ramirez-VillegasAndy Jarvis, Beatriz Herrera and Carlos Navarro

Is cassava the answer to African climate change adaptation?

Why cassava?: a main staple in Africa

• Contributed ~84 kcal/capita/day in 2007 (globally)• In Africa, however, it was 154 kcal/capita/day (387

wheat, 359 for maize, 205 rice)• Africa: ~124.3 million Ton produced in 2010 (52% of

total)

FAOSTAT (2012)

Crop hardiness: reported physiological responses

• Adapted to warm and moist areas, but can deal with dryness

Pn (

umol

CO

2 pe

r m

2/s)

El-Sharkawy (2006) El-Sharkawy and Cock (1986)

Some limiting factors

• Pests and diseases

• Low input farming systems, thus large yield gaps

Licker et al. (2010)

Herrera et al. (2011)

Potential for climate change adaptation

“In 2002, cassava was considered an ‘orphan crop’, neglected by both investors and practitioners of agricultural research”

Fauquet et al. (2012)

Potential for climate change adaptation

• No systematic approach to quantify the potential of cassava

• Lobell et al. (2008) report increases of +1.1 % (average)

• Liu et al. (2008) report little impacts on cassava yield (-2 to 1 %)

Approach

• Use a simple suitability model to quantify the response of the crop by 2030s (SRES-A1B)

• Uncertainty in projected climate quantified through the use of multiple (24) GCMs

• Compare with other staples in the region (maize, beans, sorghum, banana, millet, potato)

• Benefits of further crop improvement• Assess the impacts on pests and diseases

The EcoCrop model

Ramirez-Villegas et al. 2013 Agr. For. Met. 170: 67-78

…uses parameterised thresholds to determine climatic suitability of a particular environment…

Findings• Positive impacts or very little negative effects

Moderate to high uncertainty

Low signal

Cassava vs. other staples

Benefits of crop improvementBreeding drought /

waterloggingBreeding heat / cold

tolerance

In addition to large CO2 stimulation

Rosenthal et al. (2012) report ~100 % increases in root yield under elevated CO2

Further evidence of the crop’s potential under climate change

Under optimal management

But more work is needed on pests and diseases

Potentially less pressure

In 2012, our article empowered CIAT to play a major role in the Global Cassava Partnership 21st Century, now receiving funds from the Gates Foundation.

Conclusions• Cassava consistently outperforming

other staples in SSA under climate change• Stress-tolerant cassava for managing

risk• And also for transformational

adaptation (transition systems)• Crop improvement to further increase

biotic stress resistance