Category: Publication format

Irrigation can help smallholder farmers to compensate for the negative impacts of erratic and insufficient precipitation and significantly stabilise agricultural production (Woldemariam & Gecho, 2017). More specifically, it can raise agricultural production, allow for greater cropping intensity and crop diversity (i.e. higher-value crops), and lengthen agricultural seasons (Awulachew, 2010; Woldemariam & Gecho, 2017). Irrigation thus serves three main adaptive purposes: 1) Increasing yields by supplying water needed, 2) reducing risk due to a more constant water supply and 3) enabling multiple harvests and cultivation of high-value cash crops, as irrigation supplies water in the dry season. 

Currently, irrigation is not wide-spread yet in Ethiopia (estimates range between 2-3 % of agricultural land, with water coming from Ethiopia’s ample surface water resources), with considerable potential to upscale its usage. Stakeholder consultations, interviews, the expert survey conducted and document analysis made clear that irrigation is a key adaptation priority in Ethiopia. The Ethiopian government is aiming to transform its agricultural sector from a subsistence mode to a market-oriented one. The potential for irrigation in Ethiopia is enormous, as it has ample surface water and groundwater resources on the one hand and land suitable for irrigation on the other hand (Woldemariam & Gecho, 2017). Twelve major river basins lie in Ethiopia, which form four main drainage systems. However, there is high spatial and temporal variability (FAO, 2005; Worqlul et al., 2015). According to various studies, there is sufficient water in Ethiopia to develop around 4.5 million hectares of agricultural land that could be irrigated through pump, gravity, pressure, underground water, water harvesting and other mechanisms (Makombe et al., 2011; Woldemariam & Gecho, 2017; Worqlul et al., 2017). The hydrological analysis in Chapter 2 also confirms this and projects ample water available for irrigation in the future.

A cost-benefit analysis of switching from rainfed maize production to irrigated maize production showed that adopting irrigation is beneficial for Ethiopian farmers. Over time, irrigation has a positive return on investment (see Figure 1).  

Yet, irrigation requires a considerable investment and only becomes profitable after some years, depending on the type of irrigation system and the farm location. Institutional support is usually required and care has to be taken to avoid potential maladaptive outcomes from irrigation. Table 1 gives an overview of potential co-benefits and maladaptive outcomes from adaptation in Ethiopia. 

Constraints to adaptation uptake in Ethiopia include weak institutional capacity and lack of physical infrastructures, such as pumps, conveyance structures and storage facilities, but also access to electricity in rural areas (Awulachew, 2010; FAO, 2015b; Worqlul et al., 2017).

Overall, irrigation is an important adaptation strategy in Ethiopia with large potential to transform the agricultural sector and increase yields. Government support and careful policy design is needed to make implementation succeed.

Note to the reader: This evaluation is only to be viewed as a careful model‐based and expert assessment, which can by no means replace a thorough analysis for specific project design and local implementation planning. It gives an indication of the overall feasibility and suitability of the selected adaptation strategies in Ethiopia. Actual selection of adaptation strategies, however, should always be based on specific needs and interests of local communities.

References

• Awulachew, S. B. (2010). Irrigation potential in Ethiopia Constraints and opportunities for enhancing Irrigation potential in Ethiopia Constraints and opportunities for enhancing the system International Water Management Institute Teklu Erkossa and Regassa E . Namara. IWMI Research Report.
• FAO (UN Food and Agriculture Organization), (2005). Irrigation in Africa in figures – AQUASTAT Survey 2005, 1–14.
• FAO, (2015b): Analysis of price incentives for red sorghum in Ethiopia for the time period 2005-2012. Rome: FAO.
• Makombe, G., Namara, R., Hagos, F., Awulachew, S. B., Ayana, M., & Bossio, D. (2011). A com-parative analysis of the technical efficiency of rain-fed and smallholder irrigation in Ethiopia. IWMI Working Papers (Vol. 143). https://doi.org/10.5337/2011.202.
• Woldemariam, P., & Gecho, Y. (2017). Deter-minants of Small-Scale Irrigation Use: The Case of Boloso Sore District, Wolaita Zone, Southern Ethiopia. American Journal of Agri-culture and Forestry, 5(3), 49.
• Worqlul, A. W., Collick, A. S., Rossiter, D. G., Langan, S., & Steenhuis, T. S. (2015). Assess-ment of surface water irrigation potential in the Ethiopian highlands: The Lake Tana Basin. Catena, 129, 76–85. https://doi.org/10.1016/ j.catena.2015.02.020.
• Worqlul, A. W., Jeong, J., Dile, Y. T., Osorio, J., Schmitter, P., Gerik, T., … Clark, N. (2017). Assessing potential land suitable for surface irrigation using groundwater in Ethiopia. Applied Geography, 85, 1–13.

Temperature

In response to increasing greenhouse gas (GHG) concentrations, air temperature over Ethiopia is projected to rise by 1.6 to 3.7 °C (very likely range) by 2080 relative to the year 1876, depending on the future GHG emissions scenario (Figure 2). Compared to pre-industrial levels, median climate model temperature increases over Ethiopia amount to approximately 1.5 °C in 2030, 1.8 °C in 2050 and 1.8 °C in 2080 under the low emissions scenario RCP2.6. Under the medium / high emissions scenario RCP6.0, median climate model temperature increases amount to 1.5 °C in 2030, 1.8 °C in 2050 and 2.4 °C in 2080.

Very hot days

In line with rising mean annual temperatures, the annual number of very hot days (days with daily maximum temperature above 35 °C) is projected to rise substantially and with high certainty, in particular over eastern Ethiopia (Figure 3). Under the medium / high emissions scenario RCP6.0, on average over all Ethiopia, the multi-model median projects 18 more very hot days per year in 2030 than in 2000, 26 more in 2050 and 50 more in 2080. In some parts, especially in eastern Ethiopia, this amounts to about 200 days per year by 2080.

Precipitation

Future projections of precipitation are less certain than projections of temperature change due to high natural year-to-year variability (Figure 4). Out of the three climate models underlying this analysis, one model projects almost no change in mean annual precipitation over Ethiopia, while the other two models project an increase. Median model projections for RCP2.6 show almost no change in total precipitation per year until 2080, while median model projections for RCP6.0 show a precipitation increase of 85 mm / year by 2080 compared to year 2000.

Heavy precipitation events

In response to global warming, extreme precipitation events are expected to become more intense in many parts of the world due to the increased water vapour holding capacity of a warmer atmosphere. At the same time, the number of days with heavy precipitation events is expected to increase. This tendency is also found in climate projections for Ethiopia (Figure 5), with climate models projecting a slight increase in the number of days with heavy precipitation events, from 7 days / year in 2000 to 8 days / year in 2080 under RCP2.6 and 9 days / year under RCP6.0 by 2080.

Soil moisture

Soil moisture is an important indicator for drought conditions. In addition to soil parameters, it depends on both precipitation and evapotranspiration and therefore also on temperature as higher temperatures translate to higher potential evapotranspiration. Annual mean top 1-m soil moisture projections for Ethiopia show almost no change to a slight decrease for RCP2.6, while under RCP6.0, soil moisture is projected to slightly increase approaching a 1 % change by 2080 compared to the year 2000 (Figure 6). However, looking at the different models underlying this analysis, there is large year-to-year variability and modelling uncertainty, which makes it difficult to identify a clear trend.

Potential evapotranspiration

Potential evapotranspiration is the amount of water that would be evaporated and transpired if sufficient water were available at and below land surface. Since warmer air can hold more water vapour, it is expected that global warming will increase potential evapotranspiration in most regions of the world. In line with this expectation, hydrology projections for Ethiopia indicate a stronger and more continuous rise of potential evapotranspiration under RCP6.0 than under RCP2.6 (Figure 7). Under RCP6.0, potential evapotranspiration is projected to increase by 2.0 % in 2030, 2.7 % in 2050 and 4.4 % in 2080 compared to year 2000 levels.

5 Changes are expressed relative to year 1876 temperature levels using the multi-model median temperature change from 1876 to 2000 as a proxy for the observed historical warming over that time period.

Smallholder farmers in the global South mostly use traditional crop varieties, which can be vulnerable to climate impacts such as droughts, floods or also diseases. In order to improve the resilience of crops to climatic shocks and to raise yields, improved crop varieties are bred from traditional varieties. The process of breeding is lengthy and costly, but once better varieties are released and used, they can substantially improve agricultural yields and resilience, depending on their specific characteristics. As such, breeding improved varieties is an institution-led approach, since it requires resources and time, which smallholder farmers most often do not have.

Improved crop varieties can offer a number of interesting development co-benefits, especially linked to increased agricultural production and income. However, they are expensive to develop:  a multitude of factors will determine prices of the seeds, such as demand, scale of adoption, and – for farmers – potential government subsidies

A number of improved crop varieties already exist or are being developed in Ghana, for instance for maize, rice, cassava and cocoa, with sought-after properties being drought resistance, flood resistance and achievement of high yields. Maize appears to be the focus of breeding efforts in Ghana, as several publications (e.g. Alhassan, Salifu & Adebanji, 2016; Danso-Abbeam et al., 2017) and the number of active breeders for maize (10 out of 26) confirm (Mabaya et al., 2017).

An analysis conducted using the biophysical crop model APSIM shows that improved maize varieties indeed hold large potential for increasing yields under climate change (Figure 3). However, the size of the effect and sometimes even direction depends on the location, with the impact in different districts in Ghana differing considerably. Compared to no adaptation and other agronomic adaptation measures such as applying manure or delaying the sowing date, a carefully selected improved variety may indeed have a larger impact on increasing maize yields.

Another analysis conducted with machine-learning based crop suitability models shows how generally the effect of agronomic adaptation strategies varies considerably across crops. While maize and cassava appear to benefit from many agronomic adaptation strategies under climate change, for sorghum this is much more the case under the high-emission climate scenario (RCP8.5) and for groundnut, none of the adaptation strategies proposed has a positive effect.

Agronomic adaptation strategies and the use of improved seeds should thus be carefully evaluated for each specific region, crop and climate impact scenario. Nonetheless, improved crop varieties are seen as a transformative tool for buffering climate impacts in Ghanaian agriculture. Breeding is costly and time intensive, but where improved varieties already exist, they can contribute importantly to a higher agricultural output.

References

• Alhassan, A., Salifu, H., & Adebanji, A. O., (2016). Discriminant analysis of farmers’ adoption of improved maize varieties in Wa Municipality, Upper West Region of Ghana. SpringerPlus, 5(1).
• Danso-Abbeam, G., Bosiako, J. A., Ehiakpor, D. S., & Mabe, F. N., (2017). Adoption of improved maize variety among farm households in the northern region of Ghana. Cogent Economics and Finance, 5(1), 1–14.
• Mabaya, E., Adzivor, S. Y., Wobil, J., & Mugoya, M., (2017). Ghana Brief 2017 – The African Seed Access Index, (December).

Rainwater harvesting (RWH) allows storing irrigation water for critical times in the growing period of otherwise rain-fed crops. It is also a promising practice for reducing costs for irrigation uptake as its installation is considerably cheaper than building groundwater irrigation infrastructure.

In Ghana, limited evidence on the use and potential of RWH for small-scale irrigation systems exists. Even though Ghana has abundant water resources for irrigation, its uptake is very low. RWH can provide a cost-efficient alternative to irrigation installment and is notably a strategy with usage potential at different scales. It is particularly well suited to be coupled with farm-level horticulture production, either for additional income from vegetable sales or satisfying changing demands in household consumption (for Sub-Saharan Africa as a whole, see e.g. OECD & FAO, 2016). This could also yield nutritional and thus health benefits, with vegetables enriching otherwise staple-based diets in Ghana. A combination with conservation agriculture techniques can be particularly useful, with further improvements in soil water storage capacity enhancing the water use efficiency of RWH.

In addition, RWH has the potential to deliver gender co-benefits. Since it is usually women who are in charge of fetching water and who engage in backyard vegetable farming, collecting rainwater could save women time, making time for other activities and enabling additional farming activities.

Rainwater harvesting and small-scale irrigation are a good alternative for action at smallholder level, with simple installation techniques proving less difficult to implement, maintain and refinance as compared to large-scale irrigation systems.

Thus, RWH is a promising adaptation strategy meeting local interest in Ghana. It can be implemented by farmers autonomously and decrease dependency on precipitation.

References

• OECD/FAO, (2016). Agriculture in Sub-Saharan Africa: Prospects and challenges for the next decade, in OECD-FAO Agricultural Outlook 2016-2025, OECD Publishing, Paris. https://dx.doi.org/10.1787/agr_outlook-2016-5-en.

In areas short of precipitation, irrigation can be a key strategy to enable plant growth and increase yields. Water can be drawn from different sources, such as groundwater, surface water and in some countries even desalinated seawater, to enable a better growth of plants. Irrigation schemes at smaller scale can be initiated and implemented by farmers themselves, but for larger irrigation installations, technical agencies and extension officers play an important role.

As of yet, irrigation is not widely spread in Ghana, with only an estimated 1.6% of the area with a respective potential actually being irrigated (Mendes, Paglietti & Jackson, 2014), mostly for rice and horticulture cultivation (Namara et al., 2011). This limited uptake implies that further installation of irrigation schemes is possible and could increase Ghana’s agricultural production. However, this may incur high costs and technically challenging installation and maintenance. As a climate change adaptation strategy, the case for irrigation depends on the climate scenario, with the North of Ghana projected to see less rainfall under future climate change. However, as a measure to intensify agricultural production and enable multiple harvests, irrigation can also be considered useful today, where water is available for agricultural use.

Figure 2 shows the net value of maize production in the whole of Ghana under different irrigation scenarios, reflecting the varying costs that different irrigation techniques and installations incur. As can be seen from the comparison with the baseline scenario and the scenario under climate change, not all irrigation scenarios are able to offset the losses projected under climate change.

In sum, while irrigation has the potential to increase agricultural production in Ghana, it is also a costly strategy, often requiring institutional support for implementation and maintenance.

References

• Mendes, D.M, Paglietti, L. & Jackson, D., (2014). Ghana: Irrigation market brief. Food and Agri-culture Organization of the United Nations. Rome.
• Namara, R., Horowitz, L., Nyamadi, B. & Barry, B., (2011). Irrigation Development in Ghana: Past experiences, emerging opportunities, and future directions, International Food Policy Research Institute, GSSP Working Paper No. 27, Ghana Strategy Support Program, Accra.

Effective post-harvest management is crucial to avoid food loss along the value chain. Investments in scaling technologies for improved post-harvest management have high potential for reducing crop losses, also and especially under climate change. With climate change altering growing and harvesting seasons, post-harvest management is important to cope with increased uncertainty. It is a risk-reducing strategy that lowers the vulnerability of crop production to climate impacts. Next to main staple crops such as maize and beans, post-harvest loss (PHL) of easily perishable horticulture crops could be avoided. Numerous effective and low-cost technologies exist that can prevent or reduce PHL.

Ghana’s NDC Implementation and Investment plan lists post-harvest management as a priority for adapting agriculture to climate change, with interviews confirming wide-spread interest in such strategies. A concrete post-harvest technology with promising results in the context of maize production in Ghana have been so-called PICS bags (Purdue Improved Cowpea Storage): simple and affordable yet effective hermetic storage bags originally developed for storing cowpea. Implementation of improved post-harvest management strategies can be recommended across the country as a low-hanging fruit, since better post-harvest management can increase agricultural production considerably.

Furthermore, as the economic analysis confirmed, most post-harvest management measures are rather low cost interventions, with most intervention types being “no regret” strategies because even in the absence of climate change, the improvement in crop handling will lead to lower crop losses and higher agricultural output, being economically sensible. Figure 1 shows the net value of maize production under different post-harvest management scenarios, compared to scenarios of maize production without adaptation – both with (CC) and without climate change (BAS). Except for the highest cost scenario (MAX), all other PHM scenarios do not only make up for the maize losses under climate change, but are also able to surpass maize production under the baseline scenario (without climate change and without adaptation). This shows their high economic viability.

Overall, post-harvest management strategies have considerable potential in Ghana and, being an often low-cost and no-regret strategy, can be recommended for wider implementation.

Temperature

In response to increasing greenhouse gas (GHG) concentrations, air temperature over Ghana is projected to rise by 0.7 – 2.7°C (very likely range) by 2080 relative to year 2000, depending on the future GHG emissions scenario. Compared to 2000 levels, median climate model temperature increases over Ghana amount to approximately 0.8°C in 2030, 1.1°C in 2050, and 1.2°C in 2080 under the low emissions scenario RCP2.6. Under the medium/high emissions scenario RCP6.0, median climate model temperature increases amount to 1.0°C in 2030, 1.5°C in 2050, and 2.3°C in 2080.

Very hot days

In line with rising annual mean temperatures, the annual number of very hot days (days with daily maximum temperature greater than 35°C) is projected to rise substantially in particular over northern Ghana. Under the medium/high emission scenario RCP6.0, on average over all of Ghana, the median climate model projects 34 more very hot days per year in 2030 than in 2000, 55 more in 2050, and 94 more in 2080. In some parts, especially in the North of Ghana, this amounts to about 300 days per year by 2080.

Sea level rise

In response to globally increasing temperatures, the sea level off the coast of Ghana is projected to rise. Until 2050, very similar sea levels are projected under different GHG emissions scenarios. Under RCP6.0 and compared to year 2000 levels, the median climate model projects a sea level rise by 11 cm in 2030, 20 cm in 2050, and 39 cm in 2080. This threatens Ghana’s coastal communities and may cause saline intrusion in coastal waterways and groundwater reserves.

Precipitation

Future projections of precipitation are substantially more uncertain than projections of temperature or sea level rise. Detecting trends in annual mean precipitation projections is complicated by large natural variability at multi-decadal time scales and considerable modelling uncertainty (Figure 5). Of the four climate models underlying this analysis, one projects a decline in annual mean precipitation over Ghana. According to the other three models, there will be no change. Therefore, our best estimate is that there will be almost no change in total precipitation per year until 2080 irrespective of the emissions scenario, yet this result is highly uncertain.

Heavy precipitation events

In response to global warming, extreme precipitation events are expected to become more intense in many parts of the world due to the increased water vapor holding capacity of a warmer atmosphere. At the same time, the number of days with heavy precipitation is expected to increase. This tendency is also found in climate projections for Ghana, with climate models projecting a slight increase in the number of days with heavy precipitation events, from 7 days/year in 2000 to 8 days/year under RCP2.6 or 9 days/year under RCP6.0 by 2080. Central Ghana is subject to increased heavy precipitation, while for the far north, no change is projected by the multi-model mean.

Soil moisture

Soil moisture is an important indicator for drought conditions. In addition to soil parameters, it depends on both precipitation and evapotranspiration and therefore also on temperature as higher temperature translates to higher potential evapotranspiration. Annual mean top 1-m soil moisture projections for Ghana show a decreasing tendency. This tendency is stronger than the corresponding precipitation change projections, which reflects the influence of temperature rise on evapotranspiration.

Potential evapotranspiration

Potential evapotranspiration is the amount of water that would be evaporated and transpired if there were sufficient water available at and below the land surface. Since warmer air can hold more water vapor, it is expected that global warming will increase potential evapotranspiration in most regions of the world. In line with this expectation, hydrology projections for Ghana indicate a stronger rise of potential evapotranspiration under RCP6.0 than under RCP2.6. Specifically, under RCP6.0, compared to year 2000 levels, potential evapotranspiration is projected to increase by 3.2% in 2030, 4.6% in 2050, and 7.4% in 2080.

While most adaptation strategies seek to minimize risks stemming from climate change, not all risks can be eliminated. Weather perils such as droughts, storms or erratic precipitation represent so-called systemic risks that go beyond the farmers’ coping ability. Thus, mechanisms are needed that distribute residual risks to avoid that certain groups or individuals lose their livelihoods. One such risk transfer solution is crop insurance, which allows farmers to insure their crop yields against weather-induced losses. While insurance usually is based on indemnity assessment, this model is problematic for smallholder farmers due to the high transaction costs which insurance schemes usually entail. Thus, a more suitable approach for smallholder farmers are weather index-based insurances (WII), a scheme that uses a weather index, such as precipitation, to determine a payout. Alternative index-based insurance schemes can also be useful, such as area-yield index insurance.

Generally, insurance schemes are rather costly adaptation strategies, at least when considering the overall costs and with progressing climate change increasing the overall risk to the agricultural sector. However, insurance schemes have an important role to play for securing livelihoods: They can stabilize farm incomes and can prove to be very cost-effective for farmers when a hazard occurs.

According to the Ghana Agricultural Insurance Pool (GAIP), area-yield index insurance (AYII) as an alternative to WII has shown the biggest potential for smallholder farmers in Ghana as of yet. GAIP is a pioneer in implementing AYII in Ghana, insuring since 2011 successfully some 3000 – 4000 smallholder farmers’ cereal crops^[1] on over 18,000 acres of land. In 2017, GAIP made payouts to nearly half its insured parties.

Although AYII is a promising development, farmers’ uptake of AYII in Ghana remains limited. Balmalssaka et al. (2016), who examined the willingness of farmers in northern Ghana to participate in insurance schemes, found access to credit as well as education and experience with insurance to be important factors determining farmers’ engagement with crop insurance (Balmalssaka et al., 2016).

This indicates the need for additional incentives or financial support for taking out insurance, underlined also by Aidoo et al. (2014) who determined farmers’ willingness to pay for crop insurance in one municipality in Ghana. He concluded there was a need for government subsidies to implement it in the country (Aidoo et al., 2014). While subsidies are one strategy, experts also suggested to bundle insurance with inputs, where possible, to increase uptake.

Overall, crop insurance is a promising strategy for transferring climate risk also in Ghana. There is high interest in Ghana and demand-based roll-out of insurance pilots can be recommended. However, careful design is crucial to ensure affordability and financial sustainability.

[1] The main insured crops are: maize, sorghum, millet and groundnut.

References

• Aidoo, R., James, O., Prosper, W., & Awunyo-Vitor, D., (2014). Prospects of crop insurance as a risk management tool among arable crop farmers in Ghana. Asian Economic and Financial Review, 4(3), 341–354.
• Balmalssaka, Y., Wumbei, B. L., Buckner, J., & Nartey, R. Y., (2016). Willingness to participate in the market for crop drought index insurance among farmers in Ghana. African Journal of Agricultural Research, Vol. 11(14), 1257–1265.