**2. Methodology**

To ensure the quality of the chapter, we reviewed researched articles, review articles, books, and scientific reports only indexed by Scopus, Web of Science, Science Direct, and Google Scholar. We targeted specific keywords including "biostimulants," "drought," "food security," "agriculture sustainability," and "climate change." The articles published in well-reputed journals were studied. Moreover, the articles not related to objectives of the chapter were eliminated. The data and information collected were transformed into table and figures.

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

## **3. Impact of climate change on agriculture**

Overwhelming environmental changes have harmed agricultural production, human health, and natural systems [14]. Agriculture and climate change are linked in numerous ways since climate change is the leading driver of biotic and abiotic pressures that have detrimental effects on agriculture in an area. Concerns over the stability of the worldwide environment have led to an increase in food demand in tandem with the rapid growth of the global population. Agriculture productivity is greatly affected by water availability, air pollution, and soil quality [15]. Climate change impacts land and agriculture in many ways, including changes in yearly rainfall, heat waves, average temperature, weeds, insects, microbes, and atmospheric CO2 or ozone level.

#### **3.1 Effects on abiotic factors**

#### *3.1.1 Temperature*

Temperature affects the growth and development of plants depending on the crop being grown [16]. Climate change reduces rainfall, wind speed, and snow cover due to rising temperatures and shortens the growing season for plants, affecting crop quality and agricultural productivity [7]. The causes of temperature rise can be traced back to global warming, which varies from place to region. In the future, developing countries will be more vulnerable, which may lead to a rise in food insecurity in the region. According to a study on the effects of frost and extreme temperatures on wheat production (*Triticum aestivum* L), frost produced unfruitfulness and abortion of created grains, while excessive heat resulted in a reduction in the number of grains formed during the filling period of the grain [17]. The high-temperature effects on a pearl millet were studied by [18], and the researchers identified sensitive stages of the plant's growth process. This research assessed temperature thresholds, genetic diversity, and pollen fertility.

Moreover, the high temperature reduces pollen germination and seed production. This also impacts pollen and pistil fertility [18, 19]. Due to the effects of climate change on agricultural production, climatic variance threatens crop production patterns, causing food insecurity.

#### *3.1.2 Drought and rainfall*

One essential abiotic variable that reduces the number of agricultural products harvested worldwide is drought [20]. It influences not only the growth of the crops but also the yield value. In an experiment on miscanthus for biofuel generation, drought treatment lowered plant weight by 45% and affected biomass composition and cell wall structural stiffness [21]. Due to the distribution and pattern of precipitation in tropical regions, the water content of the soil in these regions varies significantly [22]. This means plant water in the soil is dwindling. In addition, research to investigate the impact of precipitation timing on rainforest and grassland in the United States found that plant-usable soil water content depends on precipitation [23]. In other words, when rainfall distribution is uneven, the soil water content decreases, producing stress on plants in afflicted locations. This is frequently the outcome of climate change.

#### *3.1.3 Waterlogging/flooding*

Climate change has disrupted the hydrological cycle, reducing or impairing agricultural growth in many parts of the world. As a result, waterlogging significantly impacts agricultural productivity, particularly on flatland or areas near rivers [24]. Heavy rainfall in the area is the primary source of waterlogging, although irrigation canal leaks and clean surface drainage can also contribute. Soil compaction increases, and the amount of accessible O2 for plant cells decreases because the diffusion process of O2 is sluggish in ponding water [25]. Consequently, anaerobic bacteria release iron ions, manganese ions, and sulfide in large quantities because oxygen is scarce. Physiological and morphological changes occur in crops that are waterlogged [25]. In reaction to waterlogging, a plant's stomata closes, which affects gas exchange and water uptake, as well as anaerobic conditions in the rhizosphere, harms the plant's ability to absorb water [24].

### *3.1.4 Salinity*

According to [19], worldwide salinity affects crop yield and food supplies. Since salt-sensitive crops (wheat and rice) are grown worldwide (F.A.O., 2015), salinity must be addressed soon. According to [26], rice is one of the most widely cultivated crops since it is a crucial source of sustenance for nearly all of humanity. Salinity is a stressor in dry and semiarid environments when evapotranspiration exceeds rainfall, resulting in insufficient rain to filter soluble salts from the root zone. The salinity stressor inhibits plants' capacity to absorb nutrients and water from the soil, stunting their development; salt deposits in the transpiration stream harm leaf cells, causing leaf burn; it also alters enzyme activity within the plant [27].

#### **3.2 Effects on biotic factors**

## *3.2.1 Livestock*

The focus of the cattle industry during the past quarter-century has been on enhancing production, altering the environment, and enhancing nutritional management rather than improving stress resistance. This method substantially boosted the output of domestic animals but also increased their susceptibility to hot surroundings. The modes by which domestic animals adjust to environmental changes are crucial to their survival, but they frequently have a detrimental impact on the productivity and profitability of livestock systems [28]. Heat stress has damaging effects on the health and welfare of animals. The direct and indirect impacts of heat stress on the health of farm animals in hot environments. Increased temperatures, frequency, and severity of heat waves are the primary causes of the direct consequences. These climatic circumstances can harm the health of cattle by generating metabolic changes, oxidative stress, and immunological suppression, which can lead to illnesses and mortality. Indirect consequences include changes in the availability and quality of feedstuffs and drinking water and the survival and redistribution of diseases and/or their vectors [29].
