Assessing the vulnerability of maize production to climate change in Trans Nzoia, Uasin Gishu, Nakuru and Narok counties

Abstract

Quantification of vulnerability and its components is currently an integral part of providing information to policy makers and stakeholders in an attempt to appropriately assess climate change consequences and support effective risk management and spatial planning. The aim of this study was to assess the vulnerability of maize production to climate change in Trans Nzoia, Uasin Gishu, Narok and Nakuru Counties. The trend of baseline climate patterns (1981-2010) and projected climate under RCP4.5 and RCP8.5 (2021-2050) was also assessed. Further, the relationship between climate parameters and total maize yields for the period between 2000 and 2015 was determined. The study used historical climate data obtained from Kenya Meteorological Department (KMD), simulated climate data from CORDEX for CNRM model for the period between 2021 and 2050, and biophysical and socioeconomic data from Kenya National Bureau of Statistics (KNBS), Ministry of Agriculture, Livestock and Fisheries (MOALF), and Tegemeo Institute of Agricultural Policy and Development (TIAPF). The trend analysis revealed that temperatures increased significantly while rainfall recorded a general increase which was not significant during the baseline period. Based on RCP4.5, rainfall is expected to record upward mean shift and trend patterns that will be non-significant. As for RCP8.5, the results showed that a significant upward trend of minimum and maximum temperature will be recorded in all counties during the simulation period. The correlation results showed that there was a relationship between maize yields and climate. The strength and direction of the association was varied across the maize growth stages. The results of vulnerability assessment showed that due to its least exposure index (0.19) and considerably high adaptive capacity index (2.58), Trans Nzoia registered the lowest vulnerability index of -0.21. Narok recorded the highest vulnerability index of 1.51 because of its high exposure index (1.03) which contributed greatly to potential impacts of climate stressors and hence increased its vulnerability. Moreover, its negative adaptive capacity index (-2.28) was the least among the four counties. Therefore, the county had no capacity to withstand or cope with impacts of climate change. Nakuru had the second highest vulnerability index (0.35) while Uasin Gishu was the second least vulnerable county (-0.12).