**1. Introduction**

Zimbabwe has a sub-tropical climate with four seasons: cool dry season from mid-May to August; hot dry season from September to mid- November; main rainy season from mid-November to mid-March; and the post rainy season from mid-March to mid-May [1]. The mean monthly temperature varies from 15°C in July to 24°C in November whereas the mean annual temperature varies from 18°C in the Highveld to 23°C in the Lowveld [2]. The lowest minimum temperatures (on average 7°C) are recorded in June or July and the highest maximum temperatures (on average 29°C) are recorded in October [2]. The climate is moderated by altitude with the Eastern Highlands enjoying cooler temperature compared to the low-lying areas of the Lowveld. In their research on agroecological conditions of Zimbabwe, Vincent and Thomas [1] argued that Zimbabwe was generally a semi-arid country with low annual rainfall reliability. The average annual rainfall is 650 mm but geographically it ranges from around 350 to 450 mm per year in

the Southern Lowveld to above 1,000 mm per year in the Eastern Highlands. The rainfall pattern of Zimbabwe is variable with years below and above normal rainfall [1, 3]. **Figure 1** divides the country into five agro-ecological regions on the basis of soil type, rainfall, temperature and other climatic factors. The darker colours are indicative of higher rainfall, better soils and other positive climatic indicators. These regions also represent the agricultural potential for the production of crops and livestock [1, 2, 4]. Region 1 has the highest rainfall, followed by region 2a whose rainfall amounts average the upper limits —1000 mm—of region 2 while those of region 2b average the lower limits —750 mm—of region 2. Region 5 is the most arid agro-ecological region of Zimbabwe and is the second largest agro-ecological region after region 4 (see **Figure 1**). From a climate hazard perspective, the country experiences some relatively frequent drought years which are more frequent in region 4 and 5 (see **Figure 2**).

According to Zimbabwe's Third National Communication on climate change [5], climate change in the country is characterised by high temperature and rainfall variability and extremes. The increasing frequency and severity of droughts and floods, shift in onset and cessation of the rainfall and increasing intensity of mid-season dry spells in the last 50 years have been identified in Zimbabwe's Third National Communication [5] as a major consequence of climate change. The next sections consider the temperature and rainfall changes that have occurred over the years in Zimbabwe. The annual-mean temperature in Zimbabwe has increased


#### **Figure 1.**

*Agro-ecological regions of Zimbabwe. Source: Chikozi et al. [3].*

*Climate Change Risks in Horticultural Value Chains: A Case Study from Zimbabwe DOI: http://dx.doi.org/10.5772/intechopen.97211*

#### **Figure 3.**

*Predicted mean annual temperature anomalies for Zimbabwe using various forecasting models. Source: Unganai [6].*

by about 0.4°C since 1900 [2]. The 1990s decade was the warmest experienced in Zimbabwe during the last century. Between 2000 and 2020 temperatures have also followed and upward trend with the highest average annual temperatures recorded


#### *Climate Change in Asia and Africa - Examining the Biophysical and Social Consequences…*

#### **Table 1.**

*Changes in start of growing season.*

between 2004 and 2005 (see Figures A2.3, A2.4 and A2.5 in Annex 1). There has been an overall rainfall decline of nearly 5 percent across Zimbabwe during the 20th century with the early 1990s witnessing probably the driest period in the past century [2]. Model experiments suggest that annual rainfall will continue

*Climate Change Risks in Horticultural Value Chains: A Case Study from Zimbabwe DOI: http://dx.doi.org/10.5772/intechopen.97211*

to decrease across Zimbabwe in the future [2] (also see **Figure 3**). Despite the expected rainfall reductions, there have also been substantial periods —the 1920s, 1950s, 1970s— that have been much wetter than average [2].

According to the Third National Communication [5], the Start of Season (SoS) dates for the five representative meteorological stations in each of the agro-ecological zones showed a delayed onset of the rainy season. **Table 1** shows the SoS for representative stations in each agro-ecological zone historically by Vincent and Thomas [1] together with the observed dates for contemporary Zimbabwe. According to **Table 1**, in agro-ecological region V, the rainy season in 1960 was expected to start at the end of October but had shifted to the latter parts of November between 1997 and 2014. The same applies to agro-ecological region 1 where the start of the 1960 rainy season was in late October compared to late November in 2014.

This paper presents an assessment of risks from climate change to the horticulture sector of Zimbabwe with the aim to provide mitigatory actions that could alleviate climate change risks in the horticultural sector of Zimbabwe. Specifically the paper seeks to outline the climate change risks facing the horticulture sector in Zimbabwe, propose actions to reduce risks and assess financing and policy options for climate change adaptation in Zimbabwe.
