Climate Change and Potential Hazards
The exposure of cocoa producing regions to extreme climatic events is expected to increase as climate change progresses. Prolonged dry periods and flooding are expected to be the leading determinants of crop productivity and farmer food security (Okoffo, et al. 2016). However, increasing mean temperatures, erratic precipitation, disruption of seasonal patterns, and droughts are also among the potential climate related stressors. Climate change will also affect companion species in agroforestry systems and, perhaps more importantly, cocoa pollinators, pests, and diseases. As part of the CSC approach, farmers should have the tools and capacity to reduce the impact of potential hazards, supplement incomes during lean periods, and resume production, if possible, with adequate CSC practices after extreme climatic events.
Climate Change and Potential Hazards
Temperature changes
Although temperatures below 10°C can be lethal for cocoa trees, there is no clear maximum temperature that leads to severe damage; cocoa trees have been observed to withstand temperatures of up to 52°C (Wood and Lass, 2008). Nonetheless, higher annual mean temperatures are generally linked to dryness and water stress. Very high and very low temperatures are associated with decreased photosynthesis (Zuidema, et al. 2003). High temperatures decrease the life span of leaves, increase the speed of pod ripening, which in turn increases the hardness of cocoa butter (Zuidema, et al. 2003). Moreover, temperature changes raise seedling mortality rates, may negatively affect yields, and decrease the quality and size of cocoa beans (Dohmen, et al. 2017). Pests that thrive under the new temperature conditions may pose an additional threat to yields. With increasing temperatures, farmers may choose to establish farms at higher altitudes where temperatures are more suitable for cocoa increasing the need for protecting forested uplands to prevent encroachment (Eitzinger, et al. 2015). Regional environmental characteristics, as well as cocoa genotypes, will determine the extent to which negative consequences of temperature changes materialize (Medina and Laliberte, 2017). For farmers looking to increase their resilience, agroforestry production systems are likely their best bet to mitigate the negative direct and indirect effects of temperature changes because it allows them to regulate microclimate through pruning, for example.
Climate Change and Potential Hazards
Prolonged and intensive rainfall
Dry seasons (<100mm of rainfall) longer than three months affect cocoa production negatively (Ofori, et al. 2014). Like other climate-related events, prolonged dry seasons can reduce the size of cocoa beans and lead to decreasing yields as flower abortion rates rise and wilting occurs (Dohmen, et al. 2017) (Zuidema, et al. 2003). Prolonged dry seasons are related to water stress, which reduces the life span and production of cocoa tree leaves (Zuidema, et al. 2003). Pests are also more likely to attack cocoa farms under these conditions further reducing yields, and the occurrence of bushfires also becomes more frequent under these circumstances. Water harvesting, and irrigation systems are useful CSC practices to reduce the negative effects of prolonged dry periods and droughts. Furthermore, shade trees selection in agroforestry systems should consider root depth to ensure minimal competition with cocoa trees for water.
Climate Change and Potential Hazards
Droughts
The FAO defines agricultural drought as a prolonged period (season, year(s)) of deficient rainfall compared to the average of past years resulting in insufficient soil moisture. For cocoa, precipitation of less than 1,200mm over the course of one year may lead to soil-water deficits that reduce the yields and growth rate of cocoa trees. Water availability is crucial for the development of cocoa plants and the quantity and quality of yields. Under drought conditions, cocoa seedlings quickly experience a tipping point after which they will not be able to recover (Carr and Lockwood, 2011) and some management practices, such as pesticide applications, may not have the expected results (Dohmen, et al. 2017). Droughts also result in leaf shedding (Zuidoma, et al.). Periods of drought have been on the rise since the 1950s both in terms of frequency and intensity (Flood, 2017). Agroforestry systems are generally more humid, and higher canopy cover also reduce evapotranspiration rates. Agroforestry systems with appropriate companion trees are more resilient to drought stress than other production systems (ISCR, 2017).
Climate Change and Potential Hazards
Wildfires
Extended dry periods and droughts will increase the appearance and spread of fires. Under extreme circumstances, droughts and vast wildfires can change the climatic suitability for cocoa planting of a region. Wildfires carry the additional risk to farmer’s livelihoods because of the destruction of their property (Okoffo, et al. 2016). To prevent bushfires, farmers can create fire belts along the borders of the farm and low-cost fire-fighting equipment (e.g buckets filled with sand) (Dohmen, et al. 2017). On a larger scale, fires are large contributors to greenhouse gas emissions especially when carbon sinks, like peat, are burned. Satellite imaging is vital in the assessment of large-scale fire impacts and spread for rapid action and adequate assistance.
Climate Change and Potential Hazards
Storms and winds
Intense storms can topple shade trees and cause significant damage to cocoa trees (Hutchins, et al. 2015). The high sensitivity of cocoa leaves to winds is likely to result in decreasing yields through lower light interception and higher plant stress. Moreover, strong winds facilitate the spread of cocoa diseases over large distances, especially under low air humidity (Bieng, et al. 2017). Cocoa seedlings and young trees of up to four years of age are the most vulnerable to damage caused by strong winds (Adewuyi, et al. 2014). Companion shade trees in cocoa agroforests mitigate the effects of extreme winds and storms as shade trees in the plot will reduce wind velocity (Almeida, et al. 2017; Asare, 2005; Tscharntke, et al. 2011).
A special case of wind hazards is the Harmattan in West Africa. The Harmattan winds refer to a dry wind that blows over the Sahara Desert, blowing from the northeast toward West Africa. Cocoa regions of West Africa will find themselves at an increased risk of damage from these winds which are expected to become longer in duration and spread to new areas (Schroth, et al. 2016). It is estimated that the Harmattan winds caused a loss of 150.000 MT of cocoa in 2016 (Gainusa-Bogdan, et al. 2018).
Climate Change and Potential Hazards
Flooding
Flooding refers to the inundation of land, for example due to the accumulation of rainwater (FAO, 2011). These events are not only expected to become more common in the future (FAO, 2008), but the tendency of cocoa farmers to establish new farms in wet regions as a response to droughts increases their exposure to flood related risks. Floods limit the capacity of farmers to manage their crops, increase soil nutrient leaching, change tree reactivity (the interaction between leaves, connecting tissue and absorbing roots), chronic problems may appear, and strong currents may uproot trees (Coder, 1994). Vulnerability to pests and diseases increases significantly during and after droughts. Due to the increased humidity conditions on the farm, fungal diseases like black pod spread with more ease and cause more damage (Dohmen, et al. 2017). Cocoa farms require adequate management possibly even years after the flood. To reduce their risks of damage from floods, farmers can adopt agroforestry systems with adequate companion species and contour planting. Drainage systems, trenches, and riparian forests or buffer zones can serve as additional protection (Dohmen, et al. 2017).
Climate Change and Potential Hazards
Regional challenges
Certain climate related events and risks related to climate change are more likely to be a problem in some regions than in others. Harmattan winds, for example, affect cocoa farmers in West Africa but do not have a direct effect on cocoa yields in Latin America. The occurrence and damage caused by specific climate events, such as the Harmattan winds or the El Niño Southern Oscillation (ENSO), is very difficult to assess. Differing risk exposures and climate developments at the regional level make the generation of global predictions and comparisons for cocoa a challenging task likely to render uncertain results.
Potential hazards by region
Central and South America:
– Highly exposed to ENSO (prolonged drought) (Inception report).
– Caribbean cocoa less affected by higher temperatures (Farrell, et al. 2018).
– Flooding is common. It is especially damaging in farms established on sloping land which is more vulnerable to soil erosion.
West Africa:
– Increasing dryness of dry season. Severe drought leading to increased tree mortality (Läderach, 2013) (Farrell, et al. 2018).
– The tendency to establish farms in wet regions increases vulnerability to prolonged and intensive rainfall damage.
– Ghana is particularly vulnerable to droughts and extreme temperatures because of inadequate farming practices.
– Higher frequency and intensity of floods. Average temperatures will increase 1.5 times more than globally.
– Wind speed is generally low (Mommer, et al. 1999), but the intensity and reach of harmattan winds has been expanding (Fountain and Huetz-Adams, 2018).
– Dry period length and intensity more likely to result in wildfires.
– establishment of farms next to forests and forest encroachment increases the likelihood of elephants damaging the farm and eating cocoa fruits.
Southeast Asia:
– Uncertain precipitation and extreme high temperatures are a major concern (Bunn, et al. 2017)
– Vulnerable to climatic events (most commonly droughts) due to ENSO. Yield reductions of 38% have been estimated for Indonesia during ENSO years. (Moser, et al. 2010). Prolonged dry seasons will be favorable to the spread of fires.