Impact of climate change on yields and output supply responses of selected cereal crops in Ethiopia

Abstract

Climate change affects agricultural production and productivity in sub-Saharan Africa, including Ethiopia, where it poses some threats to sustainable economic growth and ag-ricultural development. As studies conducted on the impact of climate change on crop production are limited, this study analyzed the impacts of the changes in climate on yields and output supply responses of teff, wheat and maize crops in Ethiopia.

The study employed time series secondary data on selected variables over the period of 1981 to 2018. The data were collected from various reputable sources such as the Ethio-pian CSA, NMA, and FAO data set (FAOSTAT). The study adopted Cobb-Douglas Pro-duction Function and Autoregressive Distributed Lag (ARDL) modeling approaches. The impacts of climate change on crop yields and output was estimated using key cli-mate parameters (minimum and maximum temperature and short- and long- season rainfalls). The results of Production Function analysis on the impact of climate variables on yield of cereal crops revealed that long-season rainfall have negative (-0.352, -0.498, and -0.429) and significant (at 1% and 5% levels) impact on yields of teff, wheat and maize crops, respectively. Maximum temperature also had negative (-2.810 & -3.681) and sig-nificant (at 10% level) impact on the yields of wheat and maize crops while it had posi-tive (0.372) and significant (at 10% level) impact on teff yield. Equally, the impact of climatic variables on crop output supply responses was estimated based on crop season temperature and short- and long-season rainfalls. The results indi-cated that changes in short- and long-season rainfalls had negative (-0.453 and -0.077) and significant (at 1% level) impact on wheat and maize outputs in their first lag order. The results also demonstrated that crop growing period mean temperature had negative (-2.88 and -10.70) and significant (at 1% and 5% levels) impacts on wheat and maize outputs in their first lag orders. Although temperature and long-season rainfall parame-ters showed negative impact on teff output, their impacts were minimal as they were statistically insignificant. Conversely, carbon dioxide (CO2) showed positive (4.76 and 2.256) and significant (at 5% and 1% level) impact on teff and wheat outputs in their first lag orders. This signified that teff and wheat outputs were positively responsive to an increase in CO2 concentration.

Forecasted future changes in temperature and rainfall variables showed increasing trend in mean temperature (rise from -4.850C to 0.1950C by 2080) in teff growing belt while future changes in rainfall (both short- and long-season rainfalls) showed a decreasing trend in teff (from -0.06mm to -1.58mm), wheat (from -0.11mm to -1.3mm), and maize (from -0.01mm to -0.17mm) growing belts by 2080. However, the projected future changes in the yields of wheat, maize and teff are positive over the selected scenarios. By 2080, yield of wheat would increase by 237% while those teff and maize would increase by48% and 10% respectively.

In conclusion, rainfall and temperature parameters were found to increase yield level and variability for wheat crop. However, rainfall and temperature parameters were indi-vidually found to have adverse effects on yield of teff and maize crops. Unless some abatement measures are taken on increasing CO2 emission, the rise in temperature and the decrease in seasonal rainfall will continue and this will negatively affect cereal crop yields. It is therefore recommended that there is the need to design and implement adap-tation strategies that reverse and mitigate the risks of changing climate. Development of early maturing and stress tolerant crop varieties as well as supporting research and ex-tension tasks becomes imperative.