**5. The interrelationship between drought, climate change, and food security**

Drought causes many physiological and molecular disorders in plants through excessive production of reactive oxygen species (ROS). It negatively influences the morphophysiological traits, including plant height, leaf area, relative water content, stomatal oscillation, chlorophyll contents, osmotic potential, and leaf water potential in crops [54]. Drought damages the photosynthetic process and causes stomatal closure. The reduced photosynthesis due to stomatal closure is reported to limit the supply of CO2 [55]. Food security is dependent on social, economic, and climatic factors. Climatic extremes, particularly droughts and floods, affect the state of food security in Africa [56].

One of the key predictions of climate change is that in some regions, droughts are likely to increase in frequency and severity. This will have significant implications for the long-term viability of plant populations, especially where water availability plays a key role in delineating species ranges [57]. The human influence on the earth's climate is becoming increasingly prominent. Climate observations prove the existence of a global warming trend: global average temperature has increased by 0.88°C since 1900 [58], and the 12 hottest years observed globally since 1880 all occurred between 1990 and 2005. The climate changes will also have associated consequences for biotic (frequency and effects of pest and disease outbreaks) and abiotic disturbances (changes in fire occurrence, changes in wind storm frequency and intensity) with substantial implications for forest ecosystems [59].

Public awareness of the importance of extreme climatic events is growing [60]. While longer-term climatic reconstructions suggest that the occurrence and impacts of such climatic events are not new (e.g., Acuna-Soto et al., 2005; Benson et al., 2007), there is now a growing concern that anthropogenic global warming could increase the severity and frequency of extreme climatic events in the future [60]. From an ecological perspective, climate change also represents a major threat to global biodiversity

#### **Figure 2.**

*Direct, indirect, and socioeconomic effects of climate change.*

conservation. Indeed, it is argued that in the absence of rapid implementation of strategies to reduce global greenhouse gas emissions and other processes, many of the earth's biota will likely be committed to extinction [61]. By disturbing plant populations and derived ecosystem functions that depend on complex species interactions, extreme climatic events are likely to play a central mechanistic role, which influences food security [62]. The relationship between drought and agriculture is particularly important as 84% of the damage and losses caused by droughts relate to the agriculture sector [63]. Globally, droughts and extreme heat significantly reduced national cereal production by 9–10%, whereas the analysis could not identify flood and harsh cold effects [64]. Drought disasters in Indonesia mainly occur in Java and Madura since both islands have higher risk and vulnerability than other islands (**Figure 2**) [65].

Whereas the outcomes of abiotic stresses on crop yield are hard to calculate accurately, it is believed that abiotic stresses substantially influence crop production depending upon the extent of damage to the total area under cultivation. In future, the productivity of the major crops is estimated to drop in many countries due to global warming, water shortage, and other environmental impacts [66]. To achieve food security, water must be available at the right place, at the right time, in the right quantity, and be of the right quality. Water-related disasters negatively affect agriculture and crop production, threatening food security [67].
