*3.2.2 Aquaculture and fisheries*

Aquatic ecosystems are essential to the global environment. In addition to being crucial contributors to biodiversity and ecological production, wetlands offer several

#### *Biostimulants Application: An Innovative Approach to Food Security under Drought Stress DOI: http://dx.doi.org/10.5772/intechopen.107055*

benefits to human populations, such as water for drinking and irrigation, recreational activities, and habitat for commercially significant fisheries [30]. Marine fisheries contribute significantly to people's and society's well-being, particularly in the tropics, where coastal populations rely on fisheries for food security, livelihoods, economic growth, and culture [31]. Fisheries are becoming increasingly vulnerable to changes in the physical and biogeochemical properties of the ocean (such as warming, sea-level rise, deoxygenation, acidification, and altered nutrient concentrations) caused by rising concentrations of anthropogenic greenhouse gases, particularly CO2 [32]. The distribution, abundance, and reproduction of fish and invertebrate species are also being affected by physical and biogeochemical stresses via ecosystems, directly and indirectly impacting fisheries productivity [33]. By the year 2050, climate change may cause 10–40% of species that are appropriate for marine aquaculture to become extinct in the tropics and subtropics [34].

#### *3.2.3 Insect pests*

Pests are a key biotic component also affected by climate change and weather disturbances. Temperature increases have an immediate impact on pest reproduction, survival, dissemination, population dynamics, and interactions between pests, the environment, and natural enemies. As a result, it is critical to monitor pest presence and abundance since the conditions of their occurrence might change quickly [35]. The effect of climate change on arthropod extinction rates is between 100 and 1000 times more prominent than in the past, with 45–275 species becoming extinct daily. A temperature increase of 6°C would result in the extinction of several species, including humans. In North America and Europe, bumblebee populations have decreased by 46% and 17%, respectively, because of extreme temperatures caused by climate change, compared with the base period of 1901–1974 [36]. Climate change produces new ecological niches that allow insect pests to develop and proliferate in new geographic locations and migrate from one region to another. Due to the changing environment, farmers should expect to encounter new and significant insect issues in the following years. The spread of agricultural pests across physical and political borders threatens food security and is a global issue shared by all nations and regions.

The physiology of insects is extremely sensitive to variations in temperature; as a rule, their metabolic rate will almost double for every 10°C increase in temperature [36]. Populations of whiteflies are primarily influenced by environmental conditions such as temperature, precipitation, and humidity. Whitefly population growth is favorably associated with high temperature and humidity [37]. Increased atmospheric CO2 levels can impact the distribution, number, and productivity of insects that feed on plants. Such increases may impact insect pests' growth, fertility, consumption rates, and population densities [38]. Climate change is expected to affect the amount, distribution, and seasonal timing of pests and their natural enemies, changing biological control activities [39]. Aphids are handled by natural enemies such as parasitic wasps and ladybirds. These species may react differently to temperature changes due to global warming [40].

### **4. Challenges for agricultural sustainability and food security**

Agriculture, covering more than 40 of the world's land, is the sole food provider for human beings and animals [41]. It also plays a vital role in most countries'

economic growth [42]. Furthermore, on an average basis, about 77% of the per capita energy requirements in the world are also fulfilled through crop base food products, while 23% of the remaining food comes from other sources, including meat, egg, and milk [43]. Consequently, the nutritional demand of the increasing population is one of the basic needs that can only be attained by increasing agricultural production [44]. So, in developing economies, there is a direct relationship between employment generation and poverty eradication with the progress in the agricultural sector [45]. However, this sector faces many problems but is also developing constantly through adopting various measures to handle these numerous challenges.

Climate change is likely to have harsh effects on various influences, including water resources, coastal regions, agriculture, human liveliness, food security, ecosystems and biodiversity. According to [46], climate change may predict about a 30% decrease in the yield of different crops in some parts of south and central Asia. Modifications in agricultural practices increased industrial products because of the global inevitability to assure access to nutrition on behalf of the increasing population along with the assimilation of markets and globalization (**Figure 1**) [47].

The world's food demand is increasing daily because of the increasing population. So, adequate food security is a critical problem [48]. According to the World Food Summit, food security can be defined as "when all the people in the world, any time, have economically and physically access to adequate, enough, and safe nutritious

**Figure 1.** *Need and goals to achieve agricultural sustainability.*

#### *Biostimulants Application: An Innovative Approach to Food Security under Drought Stress DOI: http://dx.doi.org/10.5772/intechopen.107055*

to fulfil their dietary requirements along with food partialities to spent healthy and active life" [49]. Food security has four main components: stability, availability, utilization, and access to food [50]. Nowadays, many challenges are faced by food security, starting from the application of various fertilizers, such as phosphorous, potassium, and nitrogen, to agricultural lands [51], then the deteriorating water tables, increasing temperatures, and an abrupt increase in population as well as consumption progression [52]. So, the two main challenges to food security are global inequity and entrepreneurial forms of production and distribution.

To cope with all these challenges, there is a need to make progress in scientific knowledge along with novel agricultural technologies that allow the communal urban agriculture practices to change with the present advanced urban agriculture. There are two types of urban agriculture, controlled environment agriculture and uncontrolled environment agriculture. According to [53], controlled environment agriculture contains agriculture practices related to environmental optimization, usually in combination with immediate urban assemblies, such as uses of greenhouse, internal farming, vertical farming, and building assimilated agriculture. While, in uncontrolled environment agriculture, vegetable farming is done in open space instead of a greenhouse and contains different types of gardens, including rooftop and community gardens that are usually indicated to play a vital role in food security globally.
