IS CASSAVA THE ANSWER TO AFRICAN CLIMATE CHANGE ADAPTATION?
Research Area on Decision and Policy Analysis (DAPA)

2030s

C...
Upcoming SlideShare
Loading in …5
×

Is Cassava the Answer to African Climate Change Adaptation?

1,009 views
758 views

Published on

Cassava reacted very well to the predicted future climate
conditions compared to other crops.

Published in: Education
1 Comment
0 Likes
Statistics
Notes
  • Busco publicación en español...
       Reply 
    Are you sure you want to  Yes  No
    Your message goes here
  • Be the first to like this

No Downloads
Views
Total views
1,009
On SlideShare
0
From Embeds
0
Number of Embeds
36
Actions
Shares
0
Downloads
20
Comments
1
Likes
0
Embeds 0
No embeds

No notes for slide

Is Cassava the Answer to African Climate Change Adaptation?

  1. 1. IS CASSAVA THE ANSWER TO AFRICAN CLIMATE CHANGE ADAPTATION? Research Area on Decision and Policy Analysis (DAPA) 2030s Climatic changes for cassavagrowing regions 38.3 (±73.9) 1.2 (±0.8) Millet Annual mean temperature change (°C) 1.7 (±1.4) Maize 1.5 (±1.1) 1.3 (±0.9) 11.4 (±31.9) 9.4 (±56.3) Cassava Beans Banana SAF NAF CAF EAF -1.8 (±25) Predicted changes in climates as average of 24 GCMs (and uncertainties expressed as standard deviations), by Africa regions. WAF area without changes Millet -1.6 (±56.2) Cassava Africa regions CAF: Central Africa SAF: South Africa EAF: East Africa SAH: Sahel NAF: North Africa WAF: West Africa Beans Banana Sorghum ! Impact assessment methods are sensitive to uncertainties in climate data, and hence these must be considered when assessing crop responses to combinations of increasing temperatures, varied precipitation patterns and increased CO2 concentrations. There was a relatively strong disagreement in GCM signals even for temperature and the uncertainty related to GCMs in rainfall was high. Potato Millet Maize ~4% NAF Beans 70% Banana In CAF, there were very little increases (<1% for all crops except potato and beans, which were predicted a substantial decrease). Sorghum Potato Millet Cassava production is located in WAF, EAF, CAF Countries with increases below 1.5 °C where the most production is located. Of overall increase in yearly predicted rainfall in the SAH. Cassava Sorghum Potato Millet BEANS (-16%±8.8) POTATO (-14.7±8.2) BANANA (-2.5%±4.9) SORGHUM (-2.66%±6.45) Whilst most areas in Africa were predicted to experience decreases in overall suitability of the additional crops modeled, cassava always outperformed or (in the worst case) equaled the average of these crops. Cassava Beans SAH Banana Sorghum Potato Millet Maize Cassava Beans WAF Impacts of climate change on cassava suitability in sub-regions of Africa (Average change in suitability) 17% Conversely, for other major food staples, we found that they are all projected to experience negative impacts, with the greatest impacts for: Maize The EcoCrop model was used in assessing the impacts of climate change. It evaluates on a 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. Predicted changes in cassava suitability as average of 24GCMs Responses in SAF were observed positive only for cassava, millet, and banana (5% each). Maize SAF Impacts of CC on cassava climate suitability In EAF, however, cassava showed the greatest potential compared to all other crops (10%), whereas beans and potatoes were the most affected. In WAF, large negative impacts were predicted for potato (-15%,), beans (-20%), and banana (-13%,), whereas millet, maize, and cassava were predicted to remain the same. Sorghum showed positive impacts (10%) Cassava >90% In SAH, responses were similar to those found in WAF Maize SAH -12.3 (±50.4) 9% area with gain in suitability 28% Potato Banana Banana -50 -25 0 Overall suitability change (%) 25  Discrimination of areas according to gains and losses using the mean change in suitability of all crops but cassava. Typology: C: cassava, O: other crops; G: increase in suitability, L: decrease in suitability. For instance, “C:G, O:L” indicates that in that area cassava (C) increases in suitability (G), and all other crops in average (O) decrease suitability (L)  Boxplots are combinations of GCM-by-country predictions. Thick black vertical lines are the median, boxes show the first and third quartile and whiskers extend 5% and 95% of the distributions WAF area with loss in suitability SAH 47% 36% ! area with loss in suitability Sorghum Beans area without changes 63% In NAF, moderate negative impacts were predicted for beans (-4%), and potato (-4%), slight positive changes for millet and banana. EAF The GCMs predicts increases in temperatures between 1.2 and 2 °C, and changes in precipitation ranged between -39 to +64 mm/year across all Africa. 1.4 (±0.9) Potato Total annual rainfall change (mm) 1.6 (±1.3) Cassava reacted very well to the predicted future climate conditions compared to other crops. Predicted changes in suitability of other staples (average among crops and GCMs) Sorghum CAF We use downscaled projections of 24 Global Climate Models (GCMs) for the SRES-A1B emissions scenario by 2030s period (2020-2049). Impacts of CC on other staple crops Impacts on pests and diseases SAF area with gain in suitability NAF Variation amongst individual GCM predictions was significant and predicted impacts with very high certainty (>80% GCMs predicting changes in the same direction). Changes in cassava climatic suitability by 2030s as predicted by EcoCrop indicate increases in the vast majority of areas, and especially seem to occur in a greater proportion over currently cropped areas and where the most significant production is reported. EAF Boxplots are combinations of GCM-by-country predictions. Thick black vertical lines are the median, boxes show the first and third quartile and whiskers extend 5% and 95% of the distributions CAF -20 -10 0 10 20 30 Overall suitability change (%) The most severe impacts were observed in WAF and the SAH, where predicted changes were negative in ~80% of the countries. 3.3 km2 negatively impacted areas 7.2 km unchanged 2 5.5 km positively impacted areas Nigeria −0.6 (±2.9) Tanzania 8.3 (±5.5) DR of the Congo −0.1 (±0.7) Angola 3.1 (±6.6) Madagascar Mozambique 5.6 (±2.7) −0.6 (±4) −3.7% to +17.5% is the projected change in suitability across the continent. Cassava is actually positively impacted in many areas of Africa. Low temperatures inhibit plant growth and reduce leaf production rate, biomass and roots yield but rarely kill the plant. Cassava is tolerant to within-season drought, but this depends on the timing, intensity and duration. 2.1 1.8 0.8 0.42 1.7 -5.5 -4.5 -8 Whitefly Mealybug Cassava mosaic disease Cassava brown streak disease Abiotic breeding priorities Many cassava-growing regions (>80% of area) are not abiotically constrained in 2030, meaning that they are unlikely to benefit from crop improvement for abiotic traits. Some cassava agroclimatological data Cassava grows optimally in the range 25–29°C although it can withstand temperatures of up to 38°C. Area likely to become pest and disease free (million km2) 0.25 Ghana -1.5 15.1 14.5 1 4.7 (±3.2) Overall suitability change 19.1 18.1 600 Uganda −0.3 (±1.5) Area predicted to improve climate suitability (million km2) 24.0 22.5 Newly affected regions (million km2) 2 Ivory Coast Current climatically suitable area (million km2) 20.5 19.2 Countries with the highest harvest area and overall suitability change (% ± SD) 0.2 (±3.2) We then examined the challenges that cassava will likely face from pests and diseases through the use of ecological niche modeling for cassava mosaic disease, whitefly, brown streak disease, and cassava mealybug. The findings show that the geographic distribution of these pests and diseases are projected to change, with both new areas opening up and areas where the pests and diseases are likely to move away or reduce in pressure. Above the optimal temperatures, cassava increases photosynthetic rates and branching. Increased drought tolerance could bring benefits to nearly 30% of cassava-growing regions in EAF, SAF, and SAH. Cold tolerance is also a priority despite the projected warmer climates. This is largely because of constraints in high-elevation regions of EAF or in low latitudinal regions in SAF where seasonal temperatures during winter pose a constraint for cassava development.   Designed by Carlos Navarro-Racines (CIAT-CCAFS 2013) e-mail:c.e.navarro@cgiar.org

×